bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Synthesis of Nano-Heterostructures (metal-metal oxide) By Thermal Oxidation for Artificial Photosynthesis Process
Authors: Cigarroa-Mayorga Oscar E. 
Published: July 2021

In this work, heterostructures based on the junction metal-metal oxide were synthesized by the accessible method of thermal oxidation. Particularly the copper oxide nanowires (CuO-Nw) with gold nanoparticles (AuNPs) and molybdenum oxide nanorods (MoO3-nr) with AuNPs are presented.
Both kind of samples were obtained from a metallic foil (Cu foil for CuO-Nw and Mo foil for MoO3-nr). The foils were cut and etched with 1 M nitric acid solution for 10 seconds, then put in deionized water for 15 min and finally isothermally heated into a horizontal furnace. The CuO-Nw with AuNPs were achieved by a two-step methodology. In the thermal treatment, the oxygen in atmosphere inside the furnace was controlled within 21 wt. % ± 1 wt. % content and a 20 L/min flux rate was used. The experiments were carried out at 400, 500 and 600 °C under a for 1h, 3h, and 5h. Afterward, Cu-O Nw were Au-coated by sputtering. with Au was coated by sputtering Au films with 10 nm and 60 nm in thickness were deposited. In order to synthetize the AuNPs a thermal treatment was isothermally performed under nitrogen atmosphere at 450 °C for 15 min. On the other hand, heterostructures formed by MoO3-nr and AuNPs were obtained by one step thermal oxidation (TO). After the cleaning step, the TO was performed on Mo foil coated with Au. The oxidation was performed into a furnace with a 20 wt. % oxygen atmosphere at 500 °C, 600 °C and 700 °C. In order to determine the relationship between oxidation time exposure and the obtained structure morphology, each experiment was performed for 1 h, 3 h and 5 h. To guaranty reproducibility, the experiments were performed by triplicated in separated experiments.
The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area of electron diffraction in each step of the synthesis process. The effect of temperature and time on density, diameter, and length of nanostructures was studied. The possible application of this kind of nano-heterostructures in the artificial photosynthesis process is discussed.
Acknowledgments
The authors acknowledge the Secretaría de Investigación y Posgrado of the Instituto Politécnico Nacional for the economic support to this work. There is no conflict of interest to disclosure.
(Invited) Mass Transport Considerations for High Performance CO2 Electrolysers
Authors: Smith Wilson 
Published: July 2021

Electrocatalytic CO2 reduction has the dual-promise of neutralizing carbon emissions in the near future, while providing a long-term pathway to create energy-dense chemicals and fuels from atmospheric and waste CO2. The field has advanced immensely in recent years, taking significant strides towards commercial realization. Gas diffusion electrodes (GDEs), composed of solid electrocatalysts on porous supports positioned near the interface of a conducting electrolyte and CO2 gas, have been able to demonstrate the substantial current densities needed for future commercialization. These higher reaction rates have often been ascribed to the presence of a three-phase interface, where solid, liquid, and gas provide electrons, water, and CO2, respectively. Conversely, mechanistic work on electrochemical reactions implicate a fully two-phase reaction interface, where gas molecules reach the electrocatalyst’s surface by dissolution and diffusion through the electrolyte. Here, we first outline the macro, micro and atomistic phenomena occurring within a gas-diffusion electrode to provide a focused introduction to the architecture of the often-discussed three-phase region for CO2 electrolysis.
In addition, we use a 2-D model to examine the concentration gradients in the gas and electrolyte flow channels across a GDE, which provides longitudinal information along the length of a flow cell. In doing so, we quantify the extent of concentration overpotentials and ohmic drops throughout the catalyst layer across a range of applied potentials and flow rates. Various process parameters were modified to explore the effects on the CO2 mass transfer-limited current density, conversion, and outlet concentrations of CO2, CO and H2. Our model suggests that ohmic losses largely determine the current density distributions at low conversion rates where small gradients in concentration exist. However, as the concentration profiles become less uniform (e.g. high conversion rates), the non-electrochemical consumption of CO2 starts to overtake electrochemical conversion, and leads to non-uniform performance across the electrode. In addition, while higher flow rates allow the ability to substantially increase current density, this comes at the expense of ohmic drops and losses in selectivity, which become more prominent at high conversion rates. The ability to understand the interplay between process conditions and local environment will be necessary to further develop the science and technology of electrochemical CO2 reduction.
(Invited) Advanced Catalysts for Efficient Electrochemical Ammonia Oxidation
Authors: Li Yi , Wu Gang 
Published: July 2021

Ammonia (NH3) has proved to be an effective alternative to hydrogen in low-temperature fuel cells via its direct ammonia oxidation reaction (AOR)(1). However, the kinetically sluggish AOR has prohibitively hindered the attractive direct ammonia fuel cell (DAFC) applications. Here, we report an efficient AOR catalyst, in which ternary PtIrM (M: Ni or Zn) alloy nanoparticles well dispersed on a binary composite support consisting of porous silicon dioxide (SiO2) and carboxyl-functionalized carbon nanotube (PtIrNi/SiO2-CNT-COOH) through a sonochemical-assisted synthesis method (2). The PtIrNi alloy nanoparticles, with the aid of abundant OHad provided by porous SiO2 and the improved electrical conductivity by CNTs, exhibit remarkable catalytic activity for the AOR in alkaline media. It is evidenced by a lower onset potential (∼0.40 V vs reversible hydrogen electrode (RHE)) at room temperature than that of commercial PtIr/C (ca. 0.43 V vs RHE). Increasing NH3 concentrations and operation temperatures can significantly enhance AOR activity of this PtIrNi nanoparticle catalyst. Specifically, the catalyst at the temperature of 80 °C exhibits a much lower onset potential (∼0.32 V vs RHE) and a higher peak current density, indicating that DAFCs operated at a higher temperature are favorable for increased performance.
References
(1) Adli, N. M.; Zhang, H.; Mukherjee, S.; Wu, G., Review—Ammonia Oxidation Electrocatalysis for Hydrogen Generation and Fuel Cells. Journal of The Electrochemical Society 2018, 165 (15), J3130-J3147.
(2) Li, Y.; Li, X.; Pillai, H. S.; Lattimer, J.; Mohd Adli, N.; Karakalos, S.; Chen, M.; Guo, L.; Xu, H.; Yang, J.; Su, D.; Xin, H.; Wu, G., Ternary PtIrNi Catalysts for Efficient Electrochemical Ammonia Oxidation. ACS Catalysis 2020, 10 (7), 3945-3957.
Efficient Bipolar Membrane Water Electrolysis Enabled By Dual-Phase CoP-CoTe2 Nanowires As Bifunctional Electrocatalyst
Authors: Amorim Isilda , Xu Junyuan , Yu Zhipeng , Bento Fátima , Liu Lifeng 
Published: July 2021

Water splitting offers an environmentally friendly way for H2 production, especially if the electricity comes from renewable sources such as solar and wind. Significant effort has recently been made to developing cheap and efficient earth-abundant electrocatalysts to make electrolyzed hydrogen economically competitive. Although the substantial progress, the operational voltage of water splitting in a single electrolyte system is still high. Given that the hydrogen evolution reaction (HER) is kinetically favorable in acidic conditions and the oxygen evolution reaction (OER) in alkaline conditions, it would be preferable to realize these half reactions simultaneously in different electrolytes in a single electrolyzer. Moreover, such cell design allows the using of low-cost and earth-abundant catalysts for both HER and OER.
In this work we demonstrate the development of a dual-phase cobalt phosphide-cobalt ditelluride (CoP-CoTe2) nanowires, which can be used as efficient bifunctional electrocatalysts for both HER and OER using acid-alkaline dual electrolytes in a two-compartment cell separated by a bipolar membrane (BPM). Using the BPM under "reverse bias" configuration, the bipolar membrane overall water splitting can be accomplished with an onset voltage as low as 1.13 V and a voltage of 1.72 V is needed to deliver 10 mA cm-2. However, water electrolysis can be accomplished at significantly lower external biases, e.g. 1.01 V at 10 mA cm-2, when a "forward bias" conditions was used due to the assistance of electrochemical neutralization. Moreover, this electrolyzer can sustain water splitting for at least 100 h. The bipolar membrane water electrolysis, particularly with the "forward bias" configuration, shows great promise as an alternative to the current technologies.
Signaling Studies of Protein-Peptide Binding on Microelectrode Arrays
Authors: White-Drayton Kendra , Liu Siyue , Moeller Kevin D 
Published: July 2021

Electrochemical methods provide unique opportunities for non-traditional synthesis and analytical studies. Using electrochemistry, we are able to synthesize addressable molecular surfaces on microelectrode arrays and then utilize the surface to probe interactions between receptors and their biological targets. To this end, the electrodes on the surface are individually addressable. They can be used as synthetic tools to generate reagents and catalysts and in so doing trigger chemical reactions on the surface of the array above the electrodes. This allows us to synthesize and/or place molecules on the arrays directly above specific individually addressable electrode in the arrays that can then be used to study the binding behavior of those molecules. While this work has shown to be successful, significant challenges still remain. While the binding signals can be observed for peptide – protein interactions on the functionalized surface of the array, the signals obtained are amplified due to avidity effects. This amplification creates difficulties when it comes to comparing the data obtained on an array to the to existing binding data in the literature. At times, it makes it difficult to quantify a binding event at all since the amplification can shift a binding curve to a point where part of it cannot be observed. Therefore, it is extremely important to develop methods by which we can calibrate the signals produced and recorded on the microelectrode arrays and optimize those signals in a reproducible way. For this reason, we have been exploring how the nature of the functionalized array surface influences the binding signal. Our work is exploring how the relative concentration of molecules on the surface of the array can be used tune the value of the binding constant measured for an interaction on a microelectrode array, how the use and length of a linker between the molecule being studied and the array can be used to optimize the intensity of the signal, and how adjusting the hydrophilicity of the functionalized surface can be used to increase the signal to noise associated with the experiments. This work will be discussed along with ways to trouble shoot experiments in connection with surface versus solution issues that can arise.
Reference: Nai-Hua Yeh, Yu Zhu, and Kevin D. Moeller*, ChemElectroChem
2019, 6, pp 4134-4143
Polyether-Cyclodextrin Modified Surfaces for Sensing of Hydrophobic Molecules
Authors: Panahi Zahra , Halpern Jeffrey M 
Published: July 2021

Electrochemical Impedance Spectroscopy (EIS) is a broadly used technique to study various surface phenomena in soft matter. For development of cyclodextrin based biosensors, we employ faradaic EIS in the presence of ferri/ferrocyanide to characterize polymer modified surfaces, investigate polymer conformational changes, and evaluate reusability and stability of the biosensors (1).
Cyclodextrins consisting of six (αCD), seven (βCD), or eight (γCD) glucose units are composed of a hydrophobic inner cavity and a hydrophilic outer surface. Hydrophobic inner cavity of cyclodextrins have made them promising candidates as molecular receptors for detection of hydrophobic molecules such as trans-resveratrol and cortisol. Health-benefiting effects of trans-resveratrol have been reported in various studies, including those reviewed by Prof. Denis Petters (2). Development of a reusable sensor platform for monitoring hydrophobic species could aid in pharmacokinetics studies and metabolite profiling of trans-resveratrol.
To make a reusable resveratrol biosensor, we first modify the gold electrode surface with polyethylene glycol (PEG). The PEG modified surface is then complexed with αCD. The αCD molecules are released from the surface in the presence of trans-resveratrol, which causes PEG molecules to flatten into a bent-over configuration which decreases the electron transfer rate. The surface can be regenerated by αCD reloading, which results in PEG chains forming microcrystalline channel-type domains and increases the electron transfer rate. With the assistance of EIS, we can confirm the charge transfer resistance increase by αCD release and charge transfer resistance increase by αCD reload. Moreover, Nyquist plots of consecutive reloading and release of αCD indicate that the PEG-αCD surface can successfully be regenerated for at least three time.
Herein, we will detail our PEG-αCD surface for the detection of resveratrol and our PPG-βCD surface for the detection of cortisol. These surfaces behave similarly in their surface configuration state and EIS analysis. Further investigation in the reusability indicates the modified gold surfaces can be reused for three times but fail when regenerated for more than four times. We assume this limitation is imposed by low stability of gold–thiol bonds, and we will discuss our progress to overcome this issue in studying the formation of more stable covalent bonds through aryl diazonium salts.

Acknowledgments: This work was supported by NIH P20 GM113131.

References

Panahi Z, Merrill MA, Halpern JM. Reusable Cyclodextrin-Based Electrochemical Platform for Detection of trans-Resveratrol. ACS Appl Polym Mater. 2020 Nov 13; 2(11):5086–93. Available from: https://dx.doi.org/10.1021/acsapm.0c00866

Rauf A, Imran M, Sulera HAR, Ahmad B, Peters DG, Mubarak MS. A comprehensive review of the health perspectives of resveratrol. Vol. 8, Food and Function. Royal Society of Chemistry; 2017. p. 4284–305. Available from: https://pubs.rsc.org/en/content/articlehtml/2017/fo/c7fo01300k
Electrocatalytic Nuclear Hydrogenation of Benzoic Acids in a Proton Exchange Membrane Reactor
Authors: Atobe Mahito , Fukazawa Atsushi , Shida Naoki 
Published: July 2021

The nuclear hydrogenation of aromatic substrates to obtain saturated cyclic compounds is of great importance in the field of chemical and pharmaceutical industry, due to its readily obtained feedstocks, environmentally friendly and straightforward routes.1 For instance, the chemoselective hydrogenation of benzoic acids to cyclohexanecarboxylic acids has attracted great attention, as the hydrogenated products cyclohexanecarboxylic acids are important organic intermediates for pharmaceuticals, such as praziquantel, caprolactam, and ansatrienin.
Several efficient catalysts based on monometallic Pd, Pt, Rh, and Ru and several alloys have been explored for the aromatic nuclear hydrogenation of benzoic acid and its derivatives.2 However, most of the catalytic reactions were performed under a high pressure of hydrogen gas, which leads to safety concerns. Therefore, the development of hydrogenation of benzoic acids to cyclohexanecarboxylic acids under mild conditions is still a challenging target.
Under these backgrounds, we have demonstrated electrocatalytic nuclear hydrogenation in a proton exchange membrane (PEM) reactor (Figure 1). This system has several merits such as easy separation and recycle use of catalysts, operation under mild and benign conditions.3 We found that the use of PEM reactor with PtRu catalyst gave the corresponding cyclohexanecarboxylic acids with excellent current efficiencies in our demonstrations.
Acknowledgement
The authors gratefully acknowledge supports by a CREST (JST Grant No.: JP65R1204400), Japan.
References

L. Zhang, J. Dong, X. L. Qiao, J. R. Qin, H. F. Sun, A. Q. Wang, L. B. Niu, G. Y. Bai, J. Catal., 372, 258–265 (2019).

D. Dwivedi, R. K. Rai, K. Gupta, S. K. Singh, ChemCatChem, 9, 1930 – 1938 (2017).

Fukazawa, J. Minoshima, K. Tanaka,Y. Hashimoto, Y. Kobori, Y. Sato, M. Atobe, ACS Sustain. Chem. Eng., 7, 11050-11055 (2019).

Figure 1
Perovskite-Type Electrolyte for Ceramic Lithium Batteries: Enhanced Microstructure and Bulk Ionic Conductivity
Authors: Yan Shuo , Merati Ali , Abu-Lebdeh Yaser , Pankov Vladimir , Yim Chae-Ho , Bauer Mackenzie , Baranova Elena , Weck Arnaud 
Published: July 2021

Solid-state lithium batteries (SSLBs) have shown great potential in energy storage applications, having the potential to enhance energy densities, while providing superior safety compared to conventional liquid electrolyte-based lithium batteries. Perovskite-type LLTO electrolytes are a promising candidate for SSLBs, due to their excellent ionic conductivities with values in excess of 10-3 S cm-1 at room temperature. However, their application in SSLBs is hindered by catastrophic dendrite formation and unstable interfaces during cycling with Lithium metal. It is also difficult to formulate electrolytes with desirable mechanical properties and high bulk ionic conductivity.
Herein, in order to understand the microstructure, bulk ionic conductivity and mechanical properties of the most studied LLTO (Li0.3La0.5TiO3), cold-press sintering was used to prepare pellets with different thicknesses using a mixture of coarse and fine LLTO powders: D50=~40μm, and D50=~1μm, respectively. This significantly enhanced the compactness and density achieved in the cold pressing stage. The sintered pellets showed a modified grain boundary pattern with an enhanced bulk ionic conductivity of 10-4-10-6 S cm-1 between 20˚C and 60˚C and a low activation energy of ~0.21eV. Symmetric cells and half-cells using the as-prepared pellets are currently being assembled for further electrochemical characterization.
Phase-Inversion Polymer Composite Separators for Printable Lithium-Ion Batteries
Authors: Katz Michelle Eileen , Cobb Corie Lynn 
Published: July 2021

Separators isolate the anode and cathode electrodes in Lithium-ion (Li-ion) batteries and play a critical role in facilitating ion transport while enabling safe battery operation. Commercial polyolefin separators made of polypropylene (PP) and polyethylene (PE) are used widely in traditional liquid electrolyte Li-ion batteries. However, these materials have limited thermal stability and are not compatible with additive manufacturing approaches for fabrication of new battery electrode architectures [1]. Researchers have investigated phase-inversion composite separators as a means to solve these problems, but there is limited data available on the relative effects of material composition and processing conditions on final separator morphology and performance. In our work, we analyze the effects of solvents, inorganic additives and phase inversion processing conditions on the separator’s ionic conductivity, rate capability, and mechanical integrity. Silica (SiO2), alumina (Al2O3), and glass particles are used as inorganic additives in varying combinations and ratios in a polyvinylidene fluoride (PVDF) polymer matrix. The PVDF concentration in our solvent solution is varied to understand the impact of solution viscosity on the phase inversion process and resultant mechanical performance of our separators. Through this study we begin to elucidate relationships between processing conditions, material composition and electrochemical and mechanical performance to facilitate further development of alternative Li-ion battery separators that are compatible with additive manufacturing.
[1] Cobb, C. L.; Ho, C. C. Electrochem. Soc. Interface
2016, 25 (1), 75–78.

Acknowledgement

This work was funded in part by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award under grant number D19AP00038. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.
Spearheading the Electrification of Chemical Manufacturing with Smart Organic Electrosynthesis
Authors: Blanco Daniela Eugenia 
Published: July 2021

Chemical innovation and new molecule development are at the heart of pharmaceutical technologies that commit to the delivery of the finest treatments for challenging diseases. Organic electrosynthesis offers multiple advantages within the industry, enabling the synthesis of new molecules and offering opportunities for more sustainable manufacturing processes through reduced waste streams, near-ambient operating conditions, and a reduced number of reaction steps. However, despite these advantages, electrochemical process development in pharma is often hindered by lengthy and complex optimization approaches, which are required to ensure the purity and selectivity necessary for successful manufacturing. In fact, developing and optimizing electrochemical reactions repeatedly requires extensive experimental campaigns to elucidate reactive behavioral trends and the effect of relevant process variables (e.g. reactant concentrations, electrode potential, temperature, pressure, flow rates) on reaction performance.
Machine-learning (ML) predictive algorithms can be used to predict reaction performance, removing the need for exhaustive experimentation in reaction discovery and process development. However, most ML-enabled systems require the use of large datasets (i.e. 100’s-1000’s of points) to deliver accurate predictions, while gathering experimental points is expensive in human and material resources. The challenge of building large datasets can be averted by developing an innovative framework around the use of supervised machine learning (SL) and active learning (AL) tools. SL models can use small datasets to predict system performance for a significantly larger number of experimental conditions. However, prediction accuracy is heavily reliant on the presence of statistically significant points in the training dataset, which can be challenging to pinpoint. To circumvent this issue, we couple SL with AL algorithms, enabling informed and smart decisions on the experimental campaign design, ultimately reducing the number of experiments required to achieve reliable predictions of reaction behavior.
Addressing fundamental questions regarding the limitations of a disruptive AL-enhanced ML predictive approach, we elucidate the pathway for the design and implementation of intelligent experimental campaigns in organic electrosynthesis. The insights from this work innovate on the future of reaction engineering and process optimization, while lowering the barrier to implementation of more sustainable electrochemical processes in pharmaceuticals and other sectors of the chemical industry.

Figure 1