bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Comparisons of Oxygen Electro-Reduction across Molecular and Extended Oxides
Authors: Thakkar Shreya , McKone James
Published: August 2024

Our work is focused on understanding hydrogen transfer in redox-active metal oxides as candidates for next-generation catalytic architectures, using oxygen electro-reduction as a model reaction. We are specifically studying the interrelationships between hydrogen transfer electrocatalysis across what we term the “molecules-to-materials design continuum” by directly comparing electrochemical properties of molecular tungsten-based polyoxometalates (polyoxotungstates) and extended tungsten oxides.

The goal of this study was to critically compare trends of activity and selectivity towards the two-electron oxygen reduction reaction using a series of three catalyst composites derived from molecular polyoxotungstates: (1) the intact molecule adsorbed on a conductive carbon support; (2) the same composite after thermal decomposition of the molecule to bulk WO3; and (3) an intermediate state comprising the partially decomposed molecule.

Catalyst composites were synthesized by wet impregnation of the polyoxotungstate (TBA)4W10O32 (TBA = tetrabutylammonium) from acetonitrile on Vulcan carbon, targeting catalyst loadings that yield well-dispersed molecular units. We then used thermal treatments over a range of temperatures associated with progressive thermal decomposition to the intermediate and fully decomposed states. Thermal decomposition reactions and products were further characterized using thermogravimetric analysis and in-situ powder X-ray diffraction. Electrocatalytic measurements were made using standard analytical protocols comprising rotating-disk electrode voltammetry of carbon-supported catalysts deposited as thin films on glassy carbon substrates.

On thermal treatment, we observed that the polyoxotungstate loses stabilizing counterions with progressive rearrangement into disordered clusters and ultimately crystalline nanoparticles of orthorhombic WO3. Each of these various forms exhibit broadly similar reactivity towards the oxygen reduction reaction. Electroanalytical results suggest all three tungsten-based composites are poor oxygen reduction catalysts with activities comparable to that of the carbon support. Nonetheless, Levich analysis suggests high selectivity for 2-electron conversion to H2O2 and catalytic onsets that correlate well with distinct voltametric features corresponding to H-activation and, in the case of extended oxides, bulk proton insertion. Ongoing work is focused on extending these studies toward more tractable hydrogen transfer reactions and identifying alternative catalysts with more thermodynamically accessible mechanisms for H activation.

More broadly, we hypothesize that these types of apples-to-apples comparisons between molecular and extended catalysts will reveal vital information about the impact of active site composition and electronic structure on H-transfer catalysis.
Electrolysis Approach of Fatty Acid Methyl Ester Production Using Alkali Hydroxides and Their Alkoxides
Authors: Aregawi Beyene , Su Chia-Hung , Wang Fu-Ming
Published: August 2024

The depletion of fossil fuels and environmental concerns have led to the search for alternative fuels (biodiesel) derived from renewable resources. Electrolysis is a promising method of fatty acid methyl ester (FAME) synthesis that can be maintained at room temperature. Nevertheless, the low reaction rates have been commonly accelerated using a combination of catalysts and electrolytes. This work proposed a novel electrolyte-free electrolysis approach for biodiesel synthesis from soybean oil using alkaline hydroxide (NaOH, KOH) and alkaline methoxide (NaOCH3, KOCH3)catalysts. Though all of them demonstrated high biodiesel yield, KOCH3 exhibitedthe highest efficiency. Based on response surface methodology, the highest FAME yield of 97.11% was achieved at optimal electrolysis voltage of 18.76V, water amount of 1.97 wt.%, KOCH3 amount of 3.17 wt.%, and methanol/oil of 21.33:1 molar, and reaction time of 60 min. The fuel properties of synthesized biodiesel agreed with international standards.The findings of this work suggest that electrolyte-free electrochemical using alkaline hydroxides and alkaline methoxides as catalysts could be a useful alternative to conventional transesterification method for producing biodiesel.

Keywords: Alkaline catalysts, Biofuel, Box–Behnken Design, Electrochemical approach
Metal Supported Metal Oxide Catalysts for Hydrogen Peroxide Production Via Water Splitting
Authors: Hamkins Kiran , Zheng Xiaolin
Published: August 2024

The two-electron water oxidation reaction (WOR) has drawn recent attention as an efficient, simple method of producing on-site hydrogen peroxide through electrochemical water splitting. However, finding electrocatalysts with high activity and stability in the reaction’s harsh oxidizing environment is challenging. This is made especially difficult due to the competing four-electron and one-electron WOR, which necessitate a catalyst material with high selectivity towards the hydrogen peroxide production pathway. Here, we utilize metal/metal oxide coupling interactions to tune metal oxide catalysts to be active for 2 e- WOR via the creation of a Mott-Schottky junction. Metal/metal oxide interactions have been well studied for supported metal catalysts, but their behavior has been less investigated for catalysts where the metal oxide provides the active sites, called inverse catalysts. In this case, the difference in work functions between the metal support and metal oxide semiconductor catalyst drives electron transfer between the two, facilitating electronic interactions which can modulate the binding energy of reaction intermediates at the interface and thus tune the catalytic ability of the metal oxide. In this work, we investigate a variety of metal oxide catalyst and metal support materials and find that a thin layer of indium tin oxide (ITO) supported by a layer of platinum (Pt) has excellent catalytic ability towards 2 e- WOR. The activity, selectivity, and stability of the ITO/Pt catalyst shows significant improvement over the unsupported ITO catalyst and yields hydrogen peroxide production rates greater than those reported in literature using other standard catalysts for this reaction. This method of catalyst engineering also provides a future pathway to create new catalysts for this electrochemical reaction.

Figure 1
Magnetically-Enhanced Electrochemical ELISA for the Detection of Sars-Cov-2 Nucleoprotein
Authors: Anderson Morgan J , Cordeiro Milton , Koehne Jessica E.
Published: August 2024

Here we report on the development of a novel, magnetically-enhanced electrochemical (MagEC) bioassay targeting SARS-CoV-2 nucleoprotein. The sensing strategy is similar to microbead-based enzyme linked immunosorbent assays (ELISA) with optical detection. The target analyte is captured using a magnetic microbead functionalized with an antibody specific to SARS-CoV-2 nucleoprotein. Once SARS-CoV-2 nucleoprotein has been captured a detection construct, consisting of polystyrene microbeads functionalized with horseradish peroxidase (HRP) and antibodies specific to SARS-CoV-2 nucleoprotein are attached to form the full microbead construct.

Once the full microbead constructs are assembled, they are injected into an electrochemical cell containing an assay solution where they are magnetically enriched at the electrode surface. This magnetic localization brings all of the reactants close to their point of detection at the electrode surface and also creates a positive feedback loop, drastically enhancing signal. The electrochemical assay was optimized using model constructs to emulate the fully assembled bead constructs and identify the optimal electrode configuration. Using the model constructs, we found a 60-fold decrease in limit of detection using the MagEC ELISA compared to optical detection with model bead constructs. We compared performance of a bare gold electrode to several geometries of gold microelectrode arrays. We obtained preliminary results for the detection of SARS-CoV-2 nucleoprotein. Additionally, the assay was expanded to incorporate a fluidic manifold to enhance signal, enhance throughput and enable operation in microgravity environments.
Stable Operation and Enhanced Sensitivity via Composite Structure Design for Efficient Photoplethysmography and Motion Sensors
Authors: Yang Zhao , Kim Byung Gi , Cho Jae Sang , Jang Woongsik , Park Keum Hwan , Park Jong Hyeok , WANG DONG Hwan
Published: August 2024

Healthcare sensors have attracted lots of interests owing to saving a patient's life by continuously monitoring the patient's health via early diagnosis of the symptoms by using healthcare sensors. Many health-care sensors are available in wearable application that can monitor continuously patient health. There are some common parameters such as a heart rate and human motion that are used to monitor human activity.

In order to realize stable operation of health-care sensors, material designs are required considering human-body compatibility. In this research, light-sensors fabricated from low-toxicity organic materials by introducing neutral poly(3,4-ethylenedioxythiophene)-(polystyrene sulfonate) (PEDOT-(PSS)) to improve human-body compatibility as well as to strengthen photoplethysmography (PPG) signal. [1] Neutral PEDOT-(PSS) with heterocyclic 1,3-diazole (HDZ) enhances the polymerization degree, carrier mobility, and other physicochemical properties. Consequently, the presented OPD-based PPG sensor has the ability to diagnose blood circulation status and cardiovascular diseases.

Second, we fabricate motion sensors by utilizing metallic glass, i.e., amorphous metallic alloy, which is an alloy composition without grain boundaries and long-range ordering. The unique structure of metallic glass results in excellent tensile strength and strain-resistivity as well as chemical stability to those of conventional metals. The Al-Sm MG-based sensors results in enhanced sensitivity and considerable device stability, because of its amorphous phase. [2]

[1] Adv. Funct. Mater. 2023, 10.1002/adfm.202309271

[2] Electrochimica Acta, 2023, 446, 142053
Pure 3D Conducting Polymer Network for an Ultra-Sensitive and Flexible Hydrogen Gas Sensor at Room Temperature
Authors: Zhigerbayeva Guldana , Nuraje Nurxat , Turlybekuly Amanzhol , Adilov Salimgerey
Published: August 2024

Hydrogen (H2) is considered a next-generation energy source with diverse applications across valuable social, economic, and industrial sectors, including transportation, biomedical, power generation, and space exploration. Due to its low ignition energy and wide flammable range, there is an urgent global demand for ultrasensitive, lightweight, portable, wearable, and flexible hydrogen sensors to identify early gas leaks and prevent environmental and economic implications.

In this study, we present a flexible hydrogen gas sensor based on conducting polymers, namely polypyrrole (PPY) with graphene nanoparticles, synthesized by the bi-continuous microemulsion polymerization method. The one-step scalable synthetic procedure enables the design of 1D, 2D, and 3D conducting polymers and their nanocomposites with tunable morphological and electrical properties. The unique multilayered oil-to-water nature of the bi-continuous microemulsion allows the fabrication of pure mesoporous 3D conducting polymers and their composites without the addition of any cross-linkers with excellent electrical properties. The 3D pure porous polymer network acts as a monolithic conducting framework that facilitates electron and ion transport and promotes the diffusion of molecules and ions more efficiently than 1D or 2D structures. The soft and porous nature of the polymer improves the interaction and adsorption of the target gas molecules and sensing material by increasing the number of active sites.

This 3D PPY_graphene flexible network synthesized by the bi-continuous microemulsion method is successfully utilized to fabricate an ultra-sensitive flexible gas sensor. The performance of the sensor can be modified based on the reactor design. The sensor exhibits a notable response to 1 ppm of H2 gas. At room temperature, the fabricated sensor displayed 14 and 20 seconds of response and recovery time, respectively. To the best of our knowledge, no study has explored the application of 3D pure conducting polymers and their nanocomposites for hydrogen gas sensors using the bi-continuous microemulsion polymerization method, yielding such exceptional sensing results.

Figure 1
Electrochemical Aptamer-Based Biosensors for Real-Time Monitoring of Biomarkers In Vivo
Authors: Soleymani Leyla , Bahkshandeh Fatemeh , Zheng Hanjia , Poudineh Mahla
Published: August 2024

There is a need for bioanalytical sensors that operate reliably for real-time monitoring of biomarkers in vivo. To address this need, we have created a hybrid sensor integrating microneedle patches with aptamer-based electrochemical sensors for monitoring glucose and lactate in vivo. We have developed a series of quality control and programmable calibration curves for measuring concentration changes in vivo. Using these methods, we have been able to monitor both lactate and glucose simultaneously in the interstitial fluid of two live animal models. Our measurements are in excellent correlation with analysis performed on blood using gold standard laboratory techniques.
(Invited) Reaction-Based Microcantilever Sensors
Authors: Ji Haifeng
Published: August 2024

Microcantilevers (MCLs) have emerged as a cost-effective, label-free, and portable analytical technique for detecting chemical and biological species. The method offers notable advantages, particularly its high sensitivity, enabling the precise detection of cantilever motion at sub-nanometer levels. Furthermore, MCLs can be effectively fabricated into a multi-element sensor array, amplifying their capabilities. While many sensors rely on adsorption-induced frequency or surface stress changes of MCLs, there is a notable gap in the literature. Despite numerous review articles on MCLs, none have specifically focused on summarizing these sensors with an emphasis on reactions. Beyond their role in detecting chemical species, MCLs present a distinctive application in characterizing the morphology and mechanical properties of materials at solid-liquid or solid-gas interfaces during reaction processes. I will discuss the reaction based MCL sensors and also their potential applications in monitoring reactions.
Direct Observation of Reversible Surface Potential in Pseudocapacitive Electrochromic Films by Kelvin Probe Force Microscopy
Authors: Dong Dongmei , Lou Lihua , Agarwal Arvind , Bhansali Shekhar
Published: August 2024

High-resolution topography and local potential images together are very powerful tools for understanding the local environment of nanomaterials. In electrochemistry, there are significant changes within the electrode materials upon charging and discharging. However, the surface changes for pseudocapacitive materials in repetitive electrochemical cycling are easily being overlooked. Thanks to the advances in Atomic Force Microscopy, it becomes feasible to visualize the electrical changes in surface upon charge transfer with Kelvin Probe Force Microscopy (KPFM) equipped with a conductive tip. We report the KPFM surface potential images and profiles of NiO electrochromic films upon bleaching (charging) and coloration (discharging). The measured surface potential is about 60 times higher in bleaching state upon charging at 20mC/cm2. What is interesting is that the potential profile shows identical topographic features with the height profile of surface morphology. The surface particles further demonstrate shape entanglement in one direction (from ~100nm to ~140nm) and shrinkage in the orthogonal direction, suggesting the charge-induced electrical stress. According to the pseudocapacitive features in the cyclic voltammetry and electrochemical impedance spectroscopy, the surface-dominant redox behavior is within expectation. Though, this dynamic surface potential change is not well studied but important, and associated with work function fluctuations and various kinds of nanoscale charge-sensitive properties, especially for efficient electrochromic supercapacitor energy storage.
High-Performance Humidity Sensor Capable for Monitoring Low-Moisture Levels in Energy Industries
Authors: Chen Zhi David David , Ali Ronak
Published: August 2024

Humidity sensors are extensively used in industrial processing and environmental control. There are two categories of humidity sensors: High-humidity (relative humidity) measurement and Low-humidity (moisture) measurement. The proper units for low-humidity measurement are dew point and parts per million in volume (ppmv) or parts per billion in volume (ppbv). It is very important to monitor moisture levels in natural gas during processing and transportation in pipelines. It is of critical importance to monitor moisture levels in lithium-ion battery manufacturing. In these cases, the moisture levels are limited to be less than -50°C dew point or 40 ppmv. The conventional relative humidity sensors cannot be used because of their low sensitivity. The dew point sensors on the market are polymer-based and gamma-phase-alumina based. The polymer-based sensors have low sensitivity, which can only accurately detect moisture levels of -60°C dew point and higher. The gamma-phase alumina sensors suffer from long-term drift due to phase change.

We present novel high-performance humidity sensors based on porous alpha-phase alumina and silicon dioxide nanostructures, which are capable of detecting moisture levels as low as -100°C dew point or 13 ppbv with excellent long-term stability. The porous alpha-phase alumina films were produced by anodic-spark-deposition on aluminum substrates in which electric sparks were produced due to high-voltage anodization (>120V). Local high-temperature (about 2200°C) at the points of sparks converted the amorphous alumina into alpha-phase alumina (Sapphire). It provides an extremely stable structure for humidity sensors. Hydrophilic silicon dioxide films deposited by atomic layer deposition was used as sensing materials. The sensors’ sensitivity, temperature coefficient, response speed, and long-term stability were studied in details. The sensors have great promise for monitoring moisture levels in natural gas industry and lithium-ion battery manufacturing.
Functionalized Graphene-Based Biosensors for Early Detection of Subclinical Ketosis in Dairy Cows
Authors: Chick Shannon , Ataei Kachouei Matin , Knowlton Katharine , Ali Azahar
Published: August 2024

Precision livestock farming is one method of improving the productivity, health, and well-being of animals. Advanced diagnostic tools including biosensors can play a key role in the management of livestock operations. Detection of ketosis, a metabolic disease that occurs in early lactation dairy cows due to the negative energy balance, is one potential on-farm use of biosensors. Beta–hydroxybutyrate (βHB) is an excellent biomarker for ketosis monitoring in dairy cows because βHB is one of the main ketones produced during this metabolic state. In this report, we develop a low-cost, Keto-sensor (graphene-based sensor) for the detection and quantification of βHB concentrations in less than a minute. In this device, graphene nanosheets were layered onto a screen–printed electrode (SPE), and then a stabilized enzyme (Beta–hydroxybutyrate dehydrogenase, NADH, and glycerol) was used to functionalize the graphene surface enabled by EDC–NHS conjugation chemistry. The Keto-sensor offers an analytical sensitivity of 10 nM and a limit-of-detection (LoD) of 0.24 nM within a detection range of 0.00001-3.0 mM. Spike testing indicates that the Keto-sensor can detect βHB in serum samples from bovines with subclinical ketosis. The Keto-sensor developed in this study shows promising results for early detection of subclinical ketosis on farms.
Propping the Electrochemical Impedance Spectra at Different Voltages Reveals the Untapped Supercapacitive Performance of Materials
Authors: Badawy Ibrahim , Elbanna Abdussalam , Ramadan Mohamed , K. Allam Nageh
Published: August 2024

Electrochemical impedance spectroscopy (EIS) is one of the most powerful and universal techniques that provides deep insights into the nature of the electrochemical system and its performance and limitations. Electric double layer capacitors (EDLCs) are electrochemical devices that can deliver and store large amounts of energy compared to traditional capacitors. The selection of an electrolyte is critical to the overall performance of EDLCs as it strongly influences the internal resistance, operating potential window, and rate capability of the device. Herein, fullerene C76 is investigated in four different electrolyte systems (Li2SO4, Na2SO4, K2SO4, and Rb2SO4) to reveal the crucial role of the electrolyte cation on the electrochemical supercapacitive performance. The Stern layer and diffuse layer formation are theorized for the electrolytes and comprehensively analysed to identify the electrolyte that provides the best system for high capacitive output. Rb+ is found to have the best conductivity and is the most responsive to applied potentials. Specifically, monitoring the EIS of the system at different applied voltages enables the unveiling of the ongoing electrochemical processes and the charge storage mechanism in detail. This approach can be generalized for various electrochemical energy storage systems to help design efficient systems and unveil the working mechanisms.
Innovative Nanoscale Ceramic Separators to Boost Cycle Life and Cycle Efficiency of Lithium Metal Batteries
Authors: Kim Je Yeon , Ryoo San Deul , Lim Ji Yang , Jung Yongju
Published: August 2024

In the pursuit of advancing energy storage, the extraordinary theoretical specific capacity of lithium metal at 3,860 mAh/g significantly outperforms traditional graphite anodes, which offer a capacity of around 372 mAh/g. This disparity underscores the potential of lithium metal batteries to facilitate a leap in energy density, heralding a new age of high-performance batteries.

Yet, the evolution of lithium metal batteries is hindered by the formation of dendritic structures during repetitive cycling, posing serious risks, including the likelihood of short circuits that underscore severe safety concerns. To mitigate these risks and enhance the longevity of lithium metal anodes, extensive research has been dedicated to various strategies, including surface modifications of lithium metal and the application of innovative coatings on separators. These strategies, however, often compromise energy density and ionic conductivity due to the addition of ceramic materials and binders.

Our study introduces a groundbreaking approach that utilizes nanoscale ceramic-coated separators, created via electron beam deposition. This method achieves a consistent nanoscale spread of metal oxide particles on conventional polyethylene (PE) separators. Crucially, this technique ensures even lithium-ion flow and greatly reduces dendrite growth. The effectiveness of this innovative approach was confirmed in comprehensive LiFePO4-Li cell tests, where cells with these ceramic-coated separators showed notable improvements in both cycle life and Coulombic efficiency, representing a significant advancement over traditional methods.
Using Micrometer Scale X-Ray CT and Pore Network Modeling to Assess High-Energy Bi-Layer Li-Ion Battery Cathode Structures
Authors: Pan Bonian
Published: August 2024

The optimization of cathode pore space is pivotal for enhancing the rate capability of lithium-ion battery electrodes. Previous studies on simulated cathodes have highlighted the importance of achieving an optimal porosity gradient, with a gradual increase from the current collector side to the separator side to accommodate the growing demand for ion transport in that direction [1]–[3]. In this research, we address this requirement by introducing and investigating bi-layer NCM 811 cathodes. These cathodes consist of a slurry-coated dense bottom layer and a spray-coated highly porous top layer with varying relative thickness to approximate the desired porosity gradient. Employing Micrometer-scale X-ray CT characterization and pore network modeling, we evaluate the structural features, demonstrating the effectiveness of the design, and quantify essential parameters such as porosity and tortuosity. Furthermore, the cathodes are integrated into lithium anode half-cells and subjected to electrochemical cycling at different rates to assess ion transport and rate capability. Our findings reveal that to achieve the highest discharge spatial energy density above 1C for cathodes approximately 100μm thick, the compressed bottom layer with 30% porosity should have a thickness of 60μm, while the highly porous top layer with around 47% porosity should be 40μm thick.

Reference:

[1] A. Shodiev et al., “Deconvoluting the benefits of porosity distribution in layered electrodes on the electrochemical performance of Li-ion batteries,” Energy Storage Mater., vol. 47, pp. 462–471, May 2022, doi: 10.1016/j.ensm.2022.01.058.

[2] X. Lu et al., “3D microstructure design of lithium-ion battery electrodes assisted by X-ray nano-computed tomography and modelling,” Nat. Commun., vol. 11, no. 1, p. 2079, Apr. 2020, doi: 10.1038/s41467-020-15811-x.

[3] K. Song, C. Zhang, N. Hu, X. Wu, and L. Zhang, “High performance thick cathodes enabled by gradient porosity,” Electrochimica Acta, vol. 377, p. 138105, May 2021, doi: 10.1016/j.electacta.2021.138105.
In-Situ X-Ray Absorption Spectroscopy Investigations on the Transition Metal Cations Intercalation in Ti3C2Tx MXene for Electrochemical Applications
Authors: Wee Shianlin , Vazquez Dario Gomez , Lian Xiliang , Tayal Akhil , Salanne Mathieu , Lukatskaya Maria
Published: August 2024

Synchrotron X-ray absorption spectroscopy (XAS) serves as a robust and powerful technique for probing the oxidation state and coordination surrounding of specific elements. In particular, operando XAS has been employed to elucidate charge storage mechanisms by monitoring changes in the oxidation state through the absorption edge energy of metals in electrodes such as MnO2 and RuO2 during charging/discharging[1]
[2]. Herein, we utilized in-situ XAS technique to uncover the charge storge mechanisms of transition metal (TM)-intercalated MXenes (Ti3C2Tx). We specifically probed the K-edges of intercalated TM and Ti MXene to reveal their oxidation states changes, shedding light on their respective contributions to capacitance. Aiming to gain further insights into the confined environment between MXene layers, we also employed ab-initio molecular dynamics (AIMD) to further interpret and validate the coordination environment obtained through in-situ extended X-ray absorption fine structure (EXAFS). This investigation lays the groundwork for tailoring the electronic and electrochemical properties of MXenes by the intercalation of various transition metal cations across diverse electrochemical systems.

[1] J.-K. Chang, M.-T. Lee, W.-T. Tsai, Journal of Power Sources
2007, 166, 590-594.

[2] Y. Mo, M. R. Antonio, D. A. Scherson, The Journal of Physical Chemistry B
2000, 104, 9777-9779.
Upcycling Plastic Waste into Porous Activated Carbon As Cathode Material for Lithium-Selenium Batteries
Authors: Ahmadian Hoseini Amir Hosein , Aboonasr Shiraz Mohammad Hossein , Arjmand Mohammad , Liu Jian
Published: August 2024

Selenium (Se) has a high specific capacity, rendering it a promising cathode material for rechargeable lithium (Li) batteries. Yet, challenges arise due to irreversible reactions and the shuttle effect in contact with electrolytes. This study addresses these issues by confining Se within a microporous carbon derived from non-recyclable plastic waste through a two-step carbonization/activation process. The resulting plastic waste-derived carbon (PWC) serves as a host for Se, forming cathode composites through a melt diffusion process. The cathode electrode was fabricated using a slurry casting method, comprising PWC/Se composite, carbon black, and sodium alginate (8:1:1 mass ratio). The evolution of the porous structure in PWC and its impact on the electrochemical performance of PWC/Se electrode were investigated for different activation temperatures (500, 600, 700, and 800 °C). The study revealed that the structure of PWC activated below 800 °C consists of mainly micropores. Moreover, by increasing the activation temperature, the specific surface area and pore volume increased, and pore size distribution shifted towards mesoporous structure. The Li-Se coin cell made from PWC activated at 600 °C (PWC600) demonstrated superior discharge capacity (640 mAh g–1 at 0.1C after 400 cycles), rate capability, and long cycling stability at higher current densities. The microporous features of PWC600 were crucial for effective Se confinement, lithium-ion diffusion, and charge transfer. This work emphasizes the sustainable development of microporous carbon from upcycled plastic waste as a promising cathode material for high-energy Li-Se batteries. Our findings contribute to environmentally friendly energy storage solutions and the circular economy by repurposing non-recyclable plastic waste into valuable materials.
Development of Coal-Derived Graphite for Lithium-Ion Batteries
Authors: Paul Abigail , Baca Isabel , Magee Regan , Wilczewski Warren , Wichert Nathan , Olson Rudolph , Al-Majali Yahya , Trembly Jason , Wolfe Kody D , Staser John A. , Garrick Taylor R.
Published: August 2024

Graphite is one of many critical minerals that are utilized in lithium-ion batteries. The requirements for domestic sourcing of critical minerals used in Li-ion batteries as outlined in the Inflation Reduction Act have generated interest in exploring alternative production methods and feedstocks for critical minerals. An alternative feedstock for the production of graphite that is being evaluated is coal. Coal is an excellent candidate as a feedstock due to its abundance in the United States and its chemical structure.

In this poster, the characterization and electrochemical performance of multiple coal-derived graphites will be presented. A focus will be put on linking electrochemical performance to the microstructure of each material. Electrochemical performance data such as initial capacity loss, gravimetric capacity and columbic efficiency will be presented for both coin and pouch cells. The application of the Multi-Species, Multi-Reaction model on coal-derived graphite will also be presented.
Ni-Pt Core-Shell Formation via Spontaneous Galvanic Displacement Reaction at Boron Doped Diamond Electrodes for Ammonia Oxidation Reaction
Authors: Omoogun Abayomi , Cabrera Carlos R.
Published: August 2024

Ammonia is a major environmental pollutant that is highly toxic and may cause unfavourable effects to the human body, even in low concentrations. As a result, the monitoring and elimination of NH3 has been an important topic worth exploring in depth. Moreover, ammonia can be a suitable fuel cell source because its theoretical electrical charge density is relatively high and it’s possible to take this advantage by converting ammonia to nitrogen and electrical energy via the ammonia oxidation reaction (AOR). This reaction requires a catalyst to decrease the energy barrier that prevents the molecule from reacting and transforming into nitrogen.

Ammonia electro-oxidation reaction has been paid much attention in recent years because it is widely used in various fields. However, the electro-oxidation of ammonia is a complex process, especially the reaction intermediate has a slow toxic effect on the electrode. To reduce the catalyst poisoning by the absorption of intermediate, the constituent and structure of the catalysts must be deeply researched.

Herein, a bimetallic Pt–Ni catalyst-modified boron-doped diamond (BDD) electrode was done via spontaneous galvanic displacement reaction for the ammonia oxidation reaction. The synergistic properties may include the promotion of low-temperature oxidation, improvement of the oxidation resistance, and increased catalytic efficiency. BDD was used as the electrode substrate in this work due to its excellent resistance to corrosion and good stability over time in a highly corrosive environment. First, nickel was electro-deposited through chronoamperometry on the BDD electrode surface at a potential of -1.1V vs Ag/AgCl in 0.1M KClO4 & 5mM Ni (NO3)2.6H2O aqueous solution. Second, platinum was deposited on the nickel particles on the BDD electrode surface through a spontaneous galvanic displacement reaction by a redox process which involves the nickel oxidation and Pt2+ reduction, using a K2PtCl4 precursor on the BDD surface while forming a core shell structure. Lastly, the Pt-Ni deposited on the BDD surface was then characterized through different techniques such as XPS, SEM, EDS, and Raman before and after the ammonia oxidation reaction.

Preliminary studies of the behaviour of BDD electrodes in the presence of Ni and Pt have been carried out to determine the electrochemical conditions at which the substrate works with these metal salts. The results found with these studies will show how Pt-Ni catalyst will improve AOR in alkaline media.
Iron Effects in Advanced Alkaline Electrolyzer
Authors: Rajeev Manasa , Kempler Paul A. , Boettcher Shannon W.
Published: August 2024

Global warming, characterized by an alarming rise in the Earth’s temperature, is one of the serious impacts of industrialization. Transition towards a sustainable future requires the diversification of our energy sources by replacing fossil fuels with renewable energy such as green H2, to lower global CO2 emissions. Alkaline water electrolysis is one of the widely used affordable water splitting techniques that produces hydrogen gas. Since Fe contamination in this system is an unavoidable factor, it is important to understand the optimum Fe concentration for maximum performance. In this work, we are investigating the change in the total cell performance by spiking Fe2+ (0 to 140 ppm) solution at industrial standard conditions (6 M KOH, 80° C).

In this work, we are investigating the change in the total cell performance by spiking Fe2+ (0 to 140 ppm) solution at industrial standard conditions (6 M KOH, 80° C). The KOH was purified prior to the experiment making sure the Fe limits are below the ICP-MS detection limit. To fully understand how Fe activates/deactivates the electrode performance, we chose NixCoy(O)OH coated on Ni mesh anode, commercial AWE cathode and Zirfon-220 as separator and performed testing in both 3-electrode set up and zero-gap electrolyzer set up. Our initial results show that, Fe effect on the total cell performance follows a bell curve where the maximum contribution comes from the activation of the anode. It must be noted that by spiking 40 -50 ppm Fe in the electrolyte the total cell potential is reduced by over 1V which is a huge gain. As we spike over 60 ppm the performance starts to go down. This can be explained by the deposition of FeOx on the anode which is a bad OER catalyst in comparison with NixCoy(O)OH. Our anode has a high active surface area from the nano sheet composition along with high conductivity from CoOx. At 20 ppm Fe in the electrolyte, the anode over potential reduced by 49 mV at 10 mA and by ~110mV at 250mA at 80 °C. Unlike bare Ni electrode as cathode, commercial cathodes are very resistant to Fe fouling only leading to a few millivolts of change. It is important to understand that Fe has maximum effect at low temperature, where the total cell potential was reduced by 200mV by adding 40 ppm Fe solution. As we increase the temperature to 80 °C, reaction kinetics gets improved and the optimum Fe concentration for maximum performance decreases.

The activation in the anode performance at high Fe concentration has been verified by studying the surface morphology SEM imaging and by taking the EDX analysis. It has been seen that the anode gives maximum performance when we have sites of NixCoyFeO(OH) deposited on the anode catalyst. As our next step, we will be evaluating the changes in the surface morphology of the cathode along with the amount of Fe being deposited at each spiking. This will provide more information on how we should engineer the cell components to achieve the maximum output.

Figure 1
Interactions of Alkali Ions and Phospholipid Monolayers at Organic-Water Interfaces
Authors: Custodio Cole , Hodkinson Evan , Hou Binyang
Published: August 2024

The self-assembled phospholipids monolayers at interfaces between two immiscible electrolyte solutions (ITIES) are commonly used to study the interactions between cell membranes and species passing in and out through membrains such as ions, drugs, and other nutrients. In this study, we utilized electrochemical techniques such as open circuit potential (OCP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) to study the pure phospholipd monolayer formed by 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and its mixture with 1,2-dioleoyl-sn-glycero-3-phospho-(1'-racglycerol) (sodium salt) (DOPG) at 1,2-dichloroethane-water interfaces. Our study has shown that at higher applied electric potentials, there seems to be no change in the facilitation of cation transfers by DOPC/DOPG monolayer compared to DOPC monolayer. However, at lower applied potentials, the DOPGs in the mixed monolayer seemed to leave the interface under the influence of the applied electric field, indicated by both the higher capacitance obtained throught the EIS measurements and the higher currents from the CV measurements compared to results obtained from the sample consisted of the pure DOPC monolayer. Furthermore, our study also showed a general rise in capacitance when incorporating heavier alkali ions in the aqueous phase for the sample with the mixture of DOPC/DOPG at higher applied electric potentials.
Rotating Disk Slurry Electrodeposition of Trimetallic Nickel-Cobalt-Iron Nanoparticles Electrocatalyst on Vulcan Xc-72R for the Oxygen Reduction Reaction in Alkaline Media
Authors: Chatterjee Suzatra , Cabrera Carlos R
Published: August 2024

Although platinum and platinum group metals (PGMs) catalysts are the most efficient for oxygen reduction reaction, the cost and scarcity of the metals are the reason to look for alternative electrocatalysts. Transition metals, such as cobalt, iron, and nickel, have shown promise as an alternative catalyst to oxygen reduction reactions (ORR). In this work, we electrochemically synthesized nickel-cobalt-iron trimetallic alloy nanoparticles dispersed on carbon Vulcan using Rotating Disk Slurry Electrodeposition (RoDSE). This technique is an energy-efficient green method to synthesize well-dispersed catalysts on carbon and oxide supports for various applications including the oxygen reduction reaction (ORR) for fuel cell applications. Cobalt-nickel iron nanoparticles have been well dispersed in 20 mg carbon Vulcan XC-72R using a negative potential (-1.05V vs Ag/AgCl-sat KCl) in a saturated Argon environment. The electrodeposition potential was obtained from cyclic voltammetry analysis of the metal salts in 0.1m KClO4 solution with an electrochemically cleaned glassy carbon electrode. The starting material precursors were iron chloride, nickel acetate, and cobalt acetate in 0.1 M KClO4 aqueous solution. A 500 micromolar metal salt solution aliquot was added for the electrodeposition every 20 minutes, with a total of 12 aliquots.

Compared with commercially available 20% Pt/Vulcan, the synthesized catalyst shows comparable mass activity and durability with an onset potential of 0.78V vs RHE(@0.01mA/cm2), limiting current density of 5.56mA/cm2 and half wave potential of 0.66V vs RHE.

The X-ray diffraction (XRD) studies and transmission electron microscopy showed that trimetallic nanoparticles are formed and deposited on the carbon Vulcan support. Moreover, scanning electron microscopy, X-ray fluorescence studies, and transmission emission microscopy show the presence of trimetallic nanoparticles. The RDE and RRDE studies show that the synthesized material is active and may lead to a good and inexpensive catalyst for ORR.
Exploring Fe Retention in Oxygen Evolution Reaction Catalysts Via Composition Engineering
Authors: Saguì Nicole Alessandra , Cannan Caitlyn W.
Published: August 2024

The oxygen evolution reaction (OER) is an electrochemical half-reaction critical to electrolyzer and metal-air battery technologies. It is well established that Ni (oxy)hydroxides are state-of-the-art electrocatalysts for the OER in basic media when Fe impurities are present in these systems. Morphological studies have shown that these catalysts are prone to dramatic nanoscale reconstruction under electrochemical conditions, implying dissolution, migration and redeposition processes of the catalyst’s components. Processes involving the displacement of Fe are especially important to understand, as these impurities, while essential for high activity at the anode, are often associated with cathode fouling. Describing the parameters that govern Fe leaching is thus of interest for the design of materials aimed toward the maintenance of device performance and longevity. To study how the degree of restructuring relates to Fe dissolution and redeposition, we have prepared a series of electrolyte accessible Ni(z)Co(1-z)O(x)H(y) (z = 0, 0.2, 0.4, ...) thin film catalysts, whereby increased amounts of Co limit the material’s dynamic behavior. By introducing tertiary cations with trackable redox features, we map a parameter space of catalyst composition more or less capable of retaining surface active phases. Parallels with Ni-Co + Fe catalysts are then carried out in Fe-free electrolyte to disrupt absorption-desorption equilibria and connect host-structure dynamics to equilibrium concentrations of electrolyte impurities.
Electrifying Chemistry: Characterizing TEMPO-Based Electrocatalysts for Isopropanol to Acetone Conversion in Novel Heat Pumps
Authors: Mishra Abhiroop , Kim Junyoung , Zorigt Michelle , Romo Adolfo I.B. , Gaddam Raghuram , Braun James , Ziviani Davide , Rodriguez Lopez Joaquin
Published: August 2024

Heating, ventilation, and air conditioning (HVAC) systems account for more than 40% of the U.S. electricity usage, primarily utilizing vapor compression system (VCS) heat pumps, raising environmental concerns. The phase down of high GWP refrigerants, targeting an 85% reduction by 2035, prompts the exploration of novel heat pump technologies. Electrochemical looping heat pumps (ELHP) show promise by employing redox reactions for fluid compression to replace conventional compression technologies. However, energy-intensive redox interconversion necessitates catalysts to lower activation energy. Inspired by electrosynthesis principles, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) emerged as a successful homogeneous electrocatalyst for selective isopropanol oxidation to acetone for use in ELHP. HPLC and 13C NMR confirmed remarkable selectivity (~100%) at practical isopropanol concentrations.

To enhance TEMPO's catalytic activity, various electron-withdrawing and donating groups were explored. TEMPO-OCH3, among seven derivatives, exhibited superior efficiency with a notable rate constant (6 M-1s-1) and turnover frequency (3.1 s-1). This study innovatively applies concepts from molecular catalysis for the development of efficient catalyst materials.
Biofluid Fouling Effects on 3D Printed Ion-Selective Electrodes for Diagnostic Sensing
Authors: Farahani Sarah , Glasco Dalton Lee , Bell Jeffrey Gordon
Published: August 2024

Research for more reliable and cost-effective sensors in healthcare applications is a global priority. This is one of the main reasons that the scientific community is pushed in development of diagnostic tools for use in point-of-care (POC) applications. The combination of electrochemistry and 3D-printing techniques in terms of POC sensor development has many advantages. Utilization of ion selective electrodes (ISEs) in potentiometric techniques has provided fast and reliable analysis as well as high selectivity for analytes in many biofluids. 3D printing, as an additive manufacturing technique, has been used in a variety of applications since it has been shown to be a low-cost and rapid fabrication technique for many sensors that can be applied in diverse POC applications. As a result, 3D-printed electrochemical sensors are used for detection of a wide range of biomarkers associated with many diseases. Several 3D printed ISEs have already been shown to selectively detect analytes in biofluids, however a comprehensive study of the effects of biofluid fouling has yet to be established. Herein, we discuss the fabrication of a novel 3D printed sodium ISE to investigate the effect of biofouling on 3D printed ISEs in comparison to conventional PVC-based ISEs. Using a custom 3D printed microfluidic device, various biofluids were introduced to understand the effects of potential ISE deterioration after prolonged use in biofluids.
Development of an Impedance and QCM-Based Electrochemical Biosensor for the Detection of Colon Cancer-Secreted Protein-2 (CCSP-2), a Potential Colorectal Cancer Biomarker
Authors: Paul Ruma , Morales-Lozada Yermary , Cabrera Carlos R.
Published: August 2024

Research on colon cancer diagnosis is advancing due to the application of electrochemical biosensors. Early screening can significantly reduce the overall mortality rate from colorectal cancer (CRC). Colon cancer-secreted protein-2 (CCSP-2) is specifically overexpressed and secreted by cancerous cells and adenomas found in the colon. Utilizing a cost-effective and non-invasive electrochemical immunosensor for CCSP-2 detection can aid in the early diagnosis of disease recurrences in individuals with colon cancer. In this work, we designed a simplified electrochemical immunosensor consisting of a functionalized gold (Au) electrode using cysteine-modified recombinant protein G (RPGCys) to immobilize the CCSP-2 antibody. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) have been used to analyze the electrochemical response caused by the binding between the target CCSP-2 and anti-CCSP-2, and there are significant changes observed for charge transfer resistance (Rct) in EIS and current density in CV. The quantification of mass changes attributed to binding events within the sensor will be determined through the application of quartz crystal microbalance (QCM). Angle-resolved X-ray photoelectron spectroscopy (ARXPS) and atomic force microscopy (AFM) will be used for the characterization of the sensor surface. The sensor's sensitivity and specificity will be assessed through the determination of the limit of detection and comprehensive testing of the probe with varied proteins and cell lines sourced from both cancerous and non-cancerous patient samples. This electrochemical probe is expected to enable the rapid and direct detection of early-stage colorectal cancer.