bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ionic Liquid Membraneless Redox Flow Battery
Authors: Chaabene Nesrine , NGO Kieu , Turmine Mireille , Vivier Vincent 
Published: July 2022

Today, ionic liquids are more and more present in many fields and more particularly in electrochemistry. Indeed, their physical and chemical properties are appealing and attractive. They are conductive solvents in which organic and inorganic salts can be dissolved depending on the nature of the anion and cation that make up the ionic liquid. However, only very few studies have reported their use in membraneless redox flow batteries (RFBs) for the storage of renewable energy 1, 2. The concept of membraneless redox-flow batteries was first reported by Ferrigno et al.3 in 2002, with the development of a millimeter-scale redox fuel cell based on the vanadium aqueous electrolyte solutions.
In this work, we have developed an ionic liquid membraneless RFB by using 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C2mimTFSI) as supporting electrolyte and Quinone (Q) and iron chloride (FeCl2) as electroactive species in a microfluidic system. Polarization curve and cyclic voltammetry were used to characterize the electrochemical properties as well as the performance of the microbattery. The proof-of-concept of the system has been shown with an open circuit potential of 0.6 V, obtained with both polarization curve and cyclic voltammetry, and with a current density ranging from 0.3 to 0.65 mA cm-2 for total flow rates of 10 to 20 µL min-1. As shown on fig. 1(b), a maximum of power of 40 µW cm-2 has been obtained. Such a technology is promising and performances can be enhanced by using 3D electrodes and optimizing the choice of the redox mediators (concentration, potential, etc.)

Figure 1: (a) Experimental set-up and polarization curves of the cell for a total flow rate of (b) 20 µL.min-1

References
1. Navalpotro, P.; Palma, J.; Anderson, M.; Marcilla, R., A Membrane-Free Redox Flow Battery with Two Immiscible Redox Electrolytes. Angew. Chem. Int. Ed. Engl.
2017,
56 (41), 12460-12465.
2. Chen, R.; Bresser, D.; Saraf, M.; Gerlach, P.; Balducci, A.; Kunz, S.; Schroder, D.; Passerini, S.; Chen, J., A Comparative Review of Electrolytes for Organic-Material-Based Energy-Storage Devices Employing Solid Electrodes and Redox Fluids. ChemSusChem
2020,
13 (9), 2205-2219.
3. Ferrigno, R.; Stroock, A. D.; Clark, T. D.; Mayer, M.; Whitesides, G. M., Membraneless vanadium redox fuel cell using laminar flow. Journal of the American Chemical Society
2002,
124 (44), 12930-12931.

Figure 1
Hot Hole Utilization in Au-TiO2 and Au-C3N4-TiO2 Core-Shell Heterojunctions for High Performance Photoelectrochemical Water Splitting
Authors: Chaulagain Narendra , Rajashekhar Harshitha , Kumar Navneet , Vahidzadeh Ehsan , Alam Kazi , Shankar Karthik 
Published: July 2022

Gold nanoparticles (Au NPs) coated with TiO2 shells exhibit strong localized surface plasmon resonance (LSPR) peaks at ~550-600 nm. The Au plasmons decay in femtoseconds through both interband and intraband damping processes to produce hot electron-hole pairs. These hot carriers have excess energy at room temperature which can be utilized to generate electricity or drive a chemical reaction. However, the hot carriers experience ultrafast recombination and thermal relaxation in hundreds of femtoseconds to a few picoseconds due to electron-electron scattering and collisions with phonons. A Schottky barrier heterojunction between Au and a n-type semiconductor such as TiO2 is an ideal method to separate the hot carrier pairs. In Au-TiO2 Schottky junctions, hot electrons are injected into TiO2 through thermionic emission and/or field emission before recombination and thermal equilibration, at timescales of roughly 250 fs. However the harvesting of residual hot holes in Au remains problematic partly because of the difficulty in forming Schottky junctions between Au and p-type semiconductors. The harvesting of hot holes is particularly important considering that hot holes in Au are on average, more energetic than hot electrons.
In this work, we use an innovative photoanode architecture to harvest hot holes. Our photoanode architecture consists of Au NPs coated with a thin layer of amorphous TiO2 and deposited on transparent conductive oxide (TCO)-coated glass substrates. Hot electrons are extracted from the Au into the TCO contact through the TiO2 shell. Hot holes tunnel through the TiO2 to reach the alkaline electrolyte whether they oxidize hydroxyl ions and dissolved oxygen species to generate oxygen. Another novelty is the use of a layer of graphitic carbon nitride (g-C3N4) quantum dots to pump the plasmon through exciton-to-plasmon energy transfer and increase the production of hot carriers. g-C3N4 works to enhance the plasmonic light harvesting due to the excellent overlap between the emission of g-C3N4 and the LSPR absorption band of Au. Photocurrent densities as high as 3.7 mA/cm2 were achieved under AM1.5G one sun illumination with concomitant high Faradaic efficiencies. Photoelectrochemical action spectra collected using filtered AM1.5G illumination and monochromatic LEDs revealed the prominent role of visible photons in water-splitting performed using Au-C3N4-TiO2 core-shell ternary heterojunctions. A key goal moving forward is to replace the noble metal (Au) with transition metal nitride plasmonic absorbers while sustaining the high level of photoelectrochemical performance.
ZIF-Based Metal-Organic Frameworks for Cantilever Gas Sensors
Authors: Akbari Masoud , Crivello Chiara , Graniel Octavio , Defort Martial , Basrour Skandar , Musselman Kevin , Muñoz-Rojas David 
Published: July 2022

Among the different gas sensing platforms, cantilever-based sensors have attracted considerable interest in recent years thanks to their ultra-sensitivity and high-speed response. The gas sensing mechanism in a dynamic cantilever sensor is based on its resonance frequency shift upon adsorption of a gas molecule on the sensor. In order to sensitize the surface of a cantilever, a sensitive receptor material with large surface area is required. Metal-organic frameworks (MOFs) are a class of nanoporous crystalline materials composed of metal ions coordinated to organic linkers. MOFs are promising for gas sensing applications as they have large surface area, rich porosity with adjustable pore size and excellent selective adsorption capability for various gasses.[1] Zeolite imidazole frameworks (ZIFs) are a class of MOFs where metals with tetrahedral coordination (i.e. Zn, Co, Fe, Cu) are the central node and the ligands are imidazolate-based organic molecules.
In this work, we developed a ZIF-based thin film for dynamic cantilever gas-sensing applications. We employed a novel atmospheric pressure spatial atomic layer deposition (AP-SALD)[2][3] technique to deposit a ZnO sacrificial layer on the silicon cantilevers. This technique allows the deposition of high-quality films at atmospheric pressure, faster than conventional ALD. The ZnO layer was then converted to a particular ZIF film with desired porosity and size, through a MOF-CVD process.[4] A gas-sensing bench setup was developed for the cantilever actuation and read-out. We present the chemical and morphological properties of the ZIF, as well as the frequency response of the sensor to various gases. The device showed reliable sensitivity to humidity, CO2 and several VOCs.

References

[1] X. F. Wang, X. Z. Song, K. M. Sun, L. Cheng, and W. Ma, “MOFs-derived porous nanomaterials for gas sensing,” Polyhedron, vol. 152, pp. 155–163, 2018.
[2] D. Muñoz-Rojas, T. Maindron, A. Esteve, F. Piallat, J. C. S. Kools, and J. M. Decams, “Speeding up the unique assets of atomic layer deposition,” Mater. Today Chem., vol. 12, pp. 96–120, 2019.
[3] K. P. Musselman, C. F. Uzoma, and M. S. Miller, “Nanomanufacturing: High-Throughput, Cost-Effective Deposition of Atomic Scale Thin Films via Atmospheric Pressure Spatial Atomic Layer Deposition,” Chem. Mater., vol. 28, no. 23, pp. 8443–8452, 2016.
[4] I. Stassen et al., “Chemical vapour deposition of zeolitic imidazolate framework thin films,” Nat. Mater., vol. 15, no. 3, pp. 304–310, 2016.
Comparison of Tenax and OV-1 Thin-Films for Microfabricated Preconcentrators
Authors: Struk Daniel , Hesketh Peter J. , Heist Christopher , Navaei Milad 
Published: July 2022

Gas chromatography is a common technique for the separation and analysis of mixtures of volatile organic compounds (VOCs). In many applications, such as breath analysis and room air sampling, the concentration of analytes is so low that preconcentration is necessary to selectively trap VOCs over a longer period of time, before analysis. The goal of this project is to develop an energy efficient, compact vapor preconcentrator for air sampling. We present thin-film preconcentrators (PCF) with integrated heaters and temperature sensors that were coated with polydimethylsiloxane (OV-1), poly(2,6-diphenylphenylene oxide) (Tenax-TA) and a mixture of OV-1 and Tenax-TA. The polymer thin-films were fabricated using a dynamic coating method with 20mg/ml OV-1 in a 1:1 mixture of DCM and pentane, 10mg/ml of OV-1 and 5mg/ml of Tenax-TA in chloroform, or 20 mg/ml of Tenax-TA in chloroform.
The OV-1 and OV-1/ Tenax-TA PCFs were initially tested by connecting them to the inlet and FID of a gas chromatograph with 1 m of 50um guard column. A volume of 0.2 µl of an alkane was injected via the heated inlet 175 oC at 1 psi, after any breakthrough had passed, the GC was pressurized to 8 psi and the PCFs were heated using an integrated platinum film heater. The GC was kept at a constant temperature of 40°C during these tests while the PCF was independently heated outside of the GC oven. The adsorption ratio of these experiments is summarized in table 1. Alkanes above decane such as dodecane proved difficult to desorb, even with the integrated heater reaching temperatures of approximately 260°C.
The air sampling experiments for each PCF were performed for decane and benzene using a dynamic headspace sampling method with a constant flow of nitrogen induced by a mass flow controller at a rate of 0.3 ml/min. at a pressure of 5psi. A six-way valve connected the PCF to the GC for desorption at a pressure of 15psi, after a set period of time. Analysis with Agilent 5890GC using a 20 m Rxi-1ms column, temperature ramp from 40°C to 180°C at a rate of 20°C/min, and FID detector. The results for the headspace sampling are summarized in figure 1. For benzene the thin-films with Tenax-TA saturate much more quickly than the OV-1 film and the pure Tenax-TA film which has the lowest capacity. For decane, the thin films with Tenax-TA still saturate faster but the largest capacity was observed for the mix of OV-1 and Tenax-TA over this limited range of sampling times.
The authors would like to thank the Georgia Tech Research Institute for funding this research out of Independent Research and Development (IRAD) funds.

Figure 1
TiO2 Nanotube Integrated Microwave Resonator UV Sensor
Authors: Alijani Mahnaz , Wiltshire Ben D. , Zarifi Mohammad H. , Macak Jan M. 
Published: July 2022

Ultraviolet (UV) irradiation is extensively utilized in numerous applications such as outer space communication, biological disinfection, memory storage, optoelectronic circuits, and biological analysis [1]. Excessive exposure to UV irradiation is deleterious and causes adverse health effects, for instance, premature aging and skin cancer. A rapid and highly sensitive device for the detection of UV is in great demand in various applications. Recently, planar microwave resonator sensors have demonstrated attractive and robust performance providing high sensitivity, real-time response, and low-cost fabrication process [2]. The planar microwave resonators can easily be integrated with nanostructured materials to make them sensitive to UV radiation via absorption and subsequent charge generation [3]. Among various wide bandgap metal oxides such as TiO2, ZnO, SnO2, one-dimensional TiO2 nanotubes (TNTs) are favorable in UV photodetectors as they possess, except intrinsic TiO2 properties high active surface area and their unique hollow geometry enables increased charge trapping and, a direct pathway for rapid transport of photogenerated carriers [4-6]. Therefore, the use of high aspect ratio (HAR) TNTs might offers superior sensing performance in the UV region.
In this presentation, the impact of TNT thicknesses on the UV sensitivity of the planar microwave resonator’s response will be investigated. We will demonstrate the use of a high frequency microwave resonator integrated with different thicknesses (50, 80, 100 µm) of TNT membranes. The presented work will aid in selecting an optimized thickness of TNT membranes with a large active surface-to-volume ratio to provide the highest sensitivity to UV irradiation. We expect this investigation to act as basis for expanding the use of HAR TNTs to effectively develop low-cost, easy to use and robust microwave UV sensors in a wide range of applications. Experimental details and recent results will be presented and discussed.
(Digital Presentation) Fabrication and Characterization of C-MEMS Based 3-Dimensional Microelectrode Arrays for Cardiac Electrophysiological Studies
Authors: Biswas Shatavisha , Datta Arkaprava , Bhattacharyya Tarun Kanti 
Published: July 2022

In-vitro examination of the electrical conduction characteristics and the beating of cardiomyocytes can be done using Microelectrode arrays(MEAs). The microelectrodes continuously monitor the electrical activity of the active cardiac cells on a microsecond timescale and presents a precise data based on that. Since the introduction of MEAs, many efforts have been made by scientists to evolve this technology by means of microfabrication. Previously, planar metallic electrodes were mostly used for this study but they could not penetrate the dead cells and reach the active cell layers. To overcome this, protruding 3-D microelectrodes were introduced that could puncture the dead tissues and reach the active cells for effective recording of cardiac electrical potentials.
The characteristics of an electrode are defined by the characteristics of the material used to develop it. In this paper, we focus on the fabrication of cylindrical 3-dimensional Glassy Carbon microelectrode arrays (MEAs) for analyzing cell preparations from cardiac tissues. In order to improve the electrical properties of the commercially available electrodes, we have used a highly conductive material for fabrication. Glassy Carbon microelectrodes were fabricated by the pyrolysis of SU-8 microelectrodes which were developed by a standard lithographic process on Silicon wafer. The ohmic nature and high conductivity of Glassy Carbon makes it a suitable material to be implemented in electrophysiological studies. Further in our work, we have performed the theoretical and structural analysis using Comsol Multiphysics 5.2 considering different geometries of microelectrodes. The skin insertion force is calculated to be 0.012N, which is much lesser than the comprehensive force (15.38N), the maximum bending force (0.885N) and the maximum buckling force (3.28N) per cylindrical microelectrode. The maximum Von Mises stress (as shown in the figure) acting at the base where it is attached to the substrate is found out to be 6.56x106 N/m2 for each cylindrical microneedle. Among all the considered geometries, it can be concluded that the fabricated cylindrical microelectrodes penetrate successfully without breaking or bending and causing minimal damage to the cardiac tissues. The slanted tip microelectrode was also favored as it’s design makes it able to easily pierce the cardiac cell layers. However, the Maximum Von Mises stress distribution showed that the stress at the tip was much higher than the Yield strength of Glassy Carbon (4Gpa) making it evident that the tip might break while penetrating. With the theoretical and simulation analysis performed we were thus able to optimize the geometry and establish that Glassy Carbon proves to be a good material for fabrication of 3D microelectrode arrays.

Figure 1
Low-Cost ITO Microelectrodes for Bio-Sensing and Impedance Based Cellular Assays
Authors: Kappalakandy Valapil Karthika , Szymon Filipiak Marcin , Rekiel Weronika , Jönsson-Niedziółka Martin , Witkowska Nery Emilia 
Published: July 2022

Excellent electronic and optical properties make Indium tin oxide (ITO) an attractive electrode substrate.1 It is an alloy of indium oxide (In2O3) and tin oxide (SnO2) in a weight ratio of 90:10. It is transparent as thin film, so, it is also good to be viewed under different types of microscopes used in cell-culture studies. Despite the commercial availability of finest quality ITO and some low-cost methods for direct deposition being in use by now, definition of patterns on them is still a concern. Placing its popularity and extensive usage aside, the manufacturing of ITO electrodes so far lacks a rapid, proficient, highly reproducible, flexible, cost-effective, easy patterning process that could surpass non-trivial, time consuming techniques as lithography. A promising advancement towards achieving these limitations was the use of lasers for the fabrication of the ITO electrodes and related structure. Even though several laser techniques are explored, with the exception of CO2 lasers, none of the others provides the benefit of being widely available and comparatively inexpensive means for fabrication of microelectrode sensors. Presently, these are the highest-power continuous wave lasers available. With their high efficiency, they are usually employed in laser cutting, welding, drilling and surface treatment.2

A cost-effective method based on CO2 laser irradiation for the preparation of ITO microelectrodes to find applications in the bio-sensing, impedance-based analysis, and more, is presented. Electrodes of different sizes and shapes were examined to identify the performance of the samples. They were later optimized to suit our applications for studies in three dimensional cell-cultures. For rectangular shaped electrodes, the smallest sizes optimized were 25, 50 and 100 µm wide. The figure attached shows cyclic voltammetry results illustrating the reproducibility of 100 µm electrodes with ferrocenedimethanol as the redox probe in potassium nitrate. However, smaller electrodes are not always desirable. For the cell-culture work, electrodes with area 1.75mm2 were fabricated and characterized to get reproducible results. Initial measurements of impedance based cellular assays have been conducted first in DMEM medium and then in the cell culture medium to understand the parameters and study the adhesion of the cells on to the electrodes. Analysis of glucose sensing properties of the system have also been attempted. Further modifications of the electrode structure and characterizations for validation will be discussed.
References

Stadler A. et al. J.Materials,
2012, 5, 661-683

Wang Y. et al. J Energy Chem. 2021, 59, 642-665

Figure 1
SAW-Based Differential Sensor Exploiting Metallocorroles Properties for Selective CO Measurement
Authors: Vanotti Meddy , Poisson Sacha , André Laurie , Brandès Stéphane , Desbois Nicolas , Gros Claude , Blondeau-Patissier Virginie 
Published: July 2022

During the last decades, the potential impact of indoor air quality on human health has stimulated an interest in hazardous compounds survey, such as carbon monoxide (CO). The detection of these compounds has consequently become a vital need. To address this issue, we propose a Surface Acoustic Wave (SAW) device functionalized with metallocorroles used for the selective detection of CO.
Here, we insist on the necessity to detect CO in the presence of interferents, such as O2 that is obviously present in the air, carbon dioxide (CO2) present in significant quantity in urban area (400 ppm) and humidity (H2O) which is a well-known interferent in the case of SAW-based gas sensors.
We will report on the interest of a differential configuration of the sensor that takes advantage of accurate organic layers, to improve the stability of the sensor’s signal and lower the sensitivity to interferents.
Acknowledgments: this work was supported by the PIA-Excellence ISITE-BFC (CoMICS program 2019-2022: Chemistry of Molecular Interactions - Catalysis and Sensors) and the ISITE CO2DECIN.
REFERENCES: [1] Di Natale, C.; Gros, C. P.; Paolesse, R., Chem. Soc. Rev.
2022, 000;[2] J.-M. Barbe, G. Canard, S. Brandès, F. Jerôme, G. Dubois, R. Guilard, Dalton Trans.
2004, 1208-1214; [3] Vanotti, M.; Poisson, S.; Soumann, V.; Quesneau, V.; Brandes, S.; Desbois, N.; Yang, J.; Andre, L.; Gros, C. P.; Blondeau-Patissier, V., Sensors and Actuators B: Chemical
2021, (332), 129507. [4] S. Brandès, V. Quesneau, O. Fonquernie, N. Desbois, V. Blondeau-Patissier, C. P. Gros, Dalton Trans. 2019, 48, 11651-11662 (Front Cover).
Fig. 1.Double delay line SAW-based CO sensor (left) and Open-loop phase measurement (Right)

Figure 1
Electrochemically Deposited Tin on High Surface Area Copper Foam for Enhanced Electrochemical Reduction of CO2 to Formic Acid
Authors: Yadavalli SIVA RAM PRASAD , Chandiran Aravind Kumar , Chetty Raghuram 
Published: July 2022

Conversion of CO2 into valuable chemicals and fuels has received widespread attention as a way to tackle the increased CO2 emissions (Gattrell, Gupta and Co, 2006) and this also resulted in a reduction of dependence on fossil fuels . There are different techniques for CO2 conversion to value-added products, where electrochemical reduction (ECR) of carbon dioxide into chemical fuels is identified as a promising way since energy efficiency is high and the products, especially the chemical fuels can be readily stored. Among the variety of metallic electrodes, especially transition metals investigated for activity towards ECR of CO2, tin (Sn), bismuth (Bi), Indium (In) were found to be selective towards formic acid production. However, it was found that these metals show a low catalytic activity.
To enhance the performance of CO2 reduction, three dimensional (3D) porous foam structured catalysts can be employed by increasing the active surface area. These 3D porous foam structures of metallic catalyst can be achieved by electrodeposition process by tuning the deposition parameters such that the evolving hydrogen during deposition can act as a dynamic template to fabricate 3D metal deposit structures with high surface areas (Shin, Dong and Liu, 2003).
In this work, a 3D foam of copper is electrochemically deposited onto Cu foil (f-Cu) and Cu mesh (f-Cu mesh). Further, the deposition parameters for the electrodeposition of Sn on 3D Cu foam (Sn/f-Cu) were optimized to investigate the activity towards the ECR of CO2. SEM and EDX technique were employed for the physical characterization of the electrodes, while the produced formic acid from the reactions was quantified using ion chromatography. The results indicated that Sn/f-Cu mesh electrode showed better performance for ECR of CO2 to formic acid compared to Sn deposited copper foil (Sn/Cu) and bare copper foam. It was observed that Sn/f-Cu mesh achieved 83 % maximum faradaic efficiency at -1.6 V vs Ag/AgCl. However, a highest rate of formic acid production of 350 µmol/hr.cm2 was achieved at -1.8 V vs Ag/AgCl which is nearly seven times higher than Sn/Cu at the same potential. A similar analysis is going to be performed with the other formic acid selective catalysts like Bi/f-Cu mesh and In/f-Cu mesh. Based on the above analysis on faradaic efficiency against various electrodes, an optimized electrode will be identified and used in scaled-up electrolyser for CO2 reduction.

References

Gattrell, M., Gupta, N. and Co, A. (2006) ‘A review of the aqueous electrochemical reduction of CO2 to hydrocarbons at copper’, Journal of Electroanalytical Chemistry, pp. 1–19. doi: 10.1016/j.jelechem.2006.05.013.
Shin, H. C., Dong, J. and Liu, M. (2003) ‘Nanoporous Structures Prepared by an Electrochemical Deposition Process’, Advanced Materials, 15(19), pp. 1610–1614. doi: 10.1002/adma.200305160.