bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Understanding CO2 and Water Supply in Zero-Gap Membrane Electrode Assembly Based Electrochemical CO2 Reduction Reaction
Authors: Hwang Yun Jeong 
Published: November 2022

Due to the global agenda to achieve net zero carbon emission, the needs to develop carbon capture and utilization technology has been sharply emerging. Although electrochemical CO2 reduction (CO2R) to useful carbon chemicals is challenging to meet the industrial requirements, recent studies have made a significant improvement in the performances both of the product selectivity and current density. Gas-diffusion electrode configurations allow direct CO2 gas-feeding to the catalyst layer and several hundred mA/cm2 of current density have been demonstrated with a zero-gap type of membrane electrolyzer assembly (MEA) electrolyzer. However, many underlying phenomena are still not clearly understood.
Among various components of MEA, here, I will focus on the cathode catalyst, and balanced CO2 / water supply at the catalyst/membrane boundary to understand the CO2R activity. We demonstrate the importance of the water supply from the anolyte for the selective CO2R in the zero-gap MEA electrolyzer. We confirm that hydrogen is mostly originated from the aqueous anolyte for the production of the ethylene from CO2R with controlled labelling experiments. In terms of the Cu catalyst morphology, the alkaline environment near the catalyst layer leads a significant morphology changes during the pre-treatment steps for the ionomer activation, which contributes to increase in the CO2R activity. The microenvironment behavior is simulated and compares with the experimental CO2R MEA performance to understand the mass flow and CO2R activity, which also support the catalyst thickness dependence. For the practical application consideration, we also study the CO2R activity for CO production with the low concentration (~ 10%) of CO2 feeding and amine-captured direct CO2 reduction condition. Weak HER activity is important especially with the low concentration of CO2 because the slower CO2 reduction rate lead to more hydrogen compared to 100 % of CO2 gas feeding. These studies will give insight to the intrinsic and extrinsic factors determining the activities of CO2R MEA.
Intrinsic Catalytic Activity and Active Phase for Oxygen Evolution in Layered Double Hydroxide Electrocatalysts
Authors: Dionigi Fabio , Zeng Zhenhua , Zhu Jing , Merzdorf Thomas , Klingenhof Malte , Li Wei-Xue , Greeley Jeffrey , Strasser Peter 
Published: November 2022

The NiFe layered double hydroxides (LDHs) are among the most active electrocatalysts for the oxygen evolution reaction (OER) in alkaline electrolytes.1 The incorporation of Fe dramatically increases the catalytic activity of Ni hydroxides.2 However, even the most active NiFe LDH catalyst still shows a considerable overpotential for the OER. Understanding the nature of the catalytic active sites and the catalytic mechanism are key challenges to develop better OER electrocatalysts.
In this contribution, atomic-scale details of the catalytic active phase will be presented, showing that NiFe LDHs are oxidized under applied anodic potentials from as-prepared α-phases to activated γ-phases.3 The interlayer and in-plane lattice parameters of the OER-active γ-phase were obtained by performing wide angle X-ray scattering (WAXS) measurements on NiFe LDH nanoplatelets during operating electrochemical conditions and were characterized by a contraction of about 8%. Operando WAXS was then performed for other selected catalysts belonging to the transition metal LDH family of materials. Structural similarities of the catalytically active phases will be highlighted.
Finally, in order to derive activity-structure relationships, an approach is presented to calculate intrinsic catalytic activities, which are challenging to evaluate for this class of materials. The presented method is based on electrochemical active surface area normalization obtained by impedance spectroscopy measurements under OER.4

References

F. Dionigi and P. Strasser, Advanced Energy Materials, 2016, 6 1600621.

L. Trotochaud, S. L. Young, J. K. Ranney and S. W. Boettcher, Journal of the American Chemical Society, 2014, 136: 6744-6753.

F. Dionigi, Z. Zeng, I. Sinev, T. Merzdorf, S. Deshpande, M. B. Lopez, S. Kunze, I. Zegkinoglou, H. Sarodnik, D. Fan, A. Bergmann, J. Drnec, J. Ferreira de Araujo, M. Gliech, D. Teschner, J. Zhu, W.-X. Li, J. Greeley, B. Roldan Cuenya and P. Strasser, Nat Commun, 2020, 11 2522.

F. Dionigi, J. Zhu, Z. Zeng, T. Merzdorf, H. Sarodnik, M. Gliech, L. Pan, W.-X. , Li, J. Greeley, and P. Strasser, Angew Chem Int Edit, 60, 14446 – 14457 (2021).
(Invited) Perspectives of Advanced Electrolysis for Green Chemicals Manufacturing
Authors: Xu Hui , Macauley Natalia , Zhang Tianyu , Zhong Sichen , Pupucevski Max , Lattimer Judith 
Published: November 2022

An electrolyzer can utilize “off peak” electricity from solar or wind farms to produce hydrogen or other fuels. These chemicals can subsequently be operated in a fuel cell mode to generate electricity or used for other industrial applications. The power to green chemicals alone is poised to become a multi-billion-dollar market for on-site water electrolysis systems over the next decade. Some examples include green H2, NH3 or hydrocarbon fuels (e.g., methanol, ethanol, and ethylene)
However, current green chemical production from electrolysis has not achieved viable commercialization due to expensive materials and low efficiency even if “free” electricity from renewable energy can be secured. Giner has been a world leader in researching, developing and manufacturing electrolyzers for green chemical synthesis. We have been committed to addressing the challenges of materials (catalyst, membrane, and bipolar plates) and processing conditions to improve electrolyzer efficiency, extend lifetime, and lower capital cost. These efforts include: 1) developing low-cost durable ion exchange membranes; 2) lowering platinum-group metal (PGM) catalyst loading; 2) discovering non-precious metal catalysts; 4) increasing corrosion resistance of separators and other hardware; 5) optimizing operating conditions.
These efforts have therefore enhanced the conversion rate and process efficiency. For example, the electrochemical production of ammonia from nitrogen and water using rationally designed catalysts can lead to tremendous energy savings compared to conventional Haber-Bosch process. The electrochemical conversion of CO2 and water to ethylene can be significantly boosted by novel membrane design and optimizing optimal operating conditions. Due to high efficiency and lowered cost, the electrolysis technologies for green chemical production may become strongly competitive and complementary to conventional chemical manufactuaring industry.
(Invited) Design of Ceramic Fuel Electrode for Solid Oxide Cells for Direct Oxidation of Hydrocarbon Fuels and for Direct CO2 Electrolysis
Authors: Chen Fanglin (Frank) (Frank) 
Published: November 2022

Large scale consumption of fossil fuels has led to the rapid increase in the atmospheric CO2 concentration, resulting in very adverse environmental concerns and frequent natural disasters. There is a grand challenge to improve conversion efficiency of fossil fuels and mitigate CO2 emmissions for terrestial applications. To enable long-term manned space exploration, there are critical needs in recycling CO2 to oxygen for life support and in situ generation of propellants using CO2 feedstock for ascent vehicles. Solid oxide cells (SOCs) have a great promise for energy conversion and storage for both terrestrial applications and space explorations. In the fuel cell mode, SOCs can convert chemical energy to electrical energy with high efficiency and fuel flexibility. In the electrolysis mode, SOCs can efficiently utilize CO2 as feedstock for chemical synthesis. The conventional Ni-based fuel electrode is vulnerable to deactivation by carbon build-up (coking) from direct oxidation of hydrocarbon fuels or for direct electrolysis of CO2, and suffers volume instability on redox cycling. This talk will report novel heterogeneous functional materials as SOC fuel electrodes that possess a combined property of good coking resistance and redox cyclability, enabling SOCs to be operated on hydrocarbon fuels for electricity generation in the fuel cell mode and for direct CO2 electrolysis for fuel synthesis in the electrolysis mode.
The general philosophy to design novel SOC fuel electrodes is to develop ceramic materials that are redox-stable, possess mixed ionic and electronic mixed conductivity, and have catalytic activities for fuel oxidation and CO2 splitting reaction. Different types of ceramic fuel electrode materials have been explored and characterized as SOC fuel electrodes. The phase formation, redox-stability, electrical conductivity, electrochemical performance, and tolerance to coking and redox-cycling have been systematically evaluated. By judicious design of ceramic-based heterogeneous functional materials, high performance redox-flexible ceramic fuel electrodes can be achieved for direct oxidation of hydrocarbon fuels and for direct CO2 electrolysis.

Acknowledgements

Financial support from the U.S. Department of Energy (DE-EE0009427), National Science Foundation (DMR–1832809) and NASA EPSCoR (Grant # 80NSSC20M0233) is greatly appreciated.
Confined Oxygen Promotes Radical Generation for Methane Oxidation Toward Liquid Oxygenates
Authors: Oh Choeulwoo , Oh Hyung-Suk 
Published: November 2022

The activation of methane (CH4) gas to produce value-added liquid hydrocarbons has been a challenging issue in catalytic research. Electrochemical oxidation is one of the alternative methods to oxidize methane and can be usually performed at ambient temperature, which can solve the problems of methane steam reforming caused by high temperature. However, electrochemical direct methane oxidation still have limitations that it should competes with oxygen evolution reaction, resulting in low efficiency. Also, oxygenates generated from methane oxidation can be easily overoxidized to carbon dioxide which is not appropriate product for the purpose of electrochemical system to make liquid hydrocarbons , suggesting solution to transport problem in the industry.
Therefore, we suggest new system to convert methane into liquid products via oxygen reduction reaction using cathode. Recently in some papers, oxygen is used as an oxidant in photocatalytic system to oxidize methane into liquid hydrocarbons. Herein, hydrogen peroxide (H2O2) generated from oxygen reduction reaction can produce hydroxyl radical, superoxide radical, and hydroperoxide radical with strong activity to break first C-H bond from CH4. By combining methyl radical activated from methane and radicals generated from H2O2, we could make formic acid with high selectivity. Through the reduction reaction on cathode and oxidation reaction by radicals, intermediate products, such as methanol and methyl hydroperoxide, were finally converted into formic acid. Furthermore, overoxidation, one of important limitation in direct methane oxidation, can be prevented by using cathode where reduction reaction occurs on electrode.
In this work, we synthesized metal organic framework (MOF)-derived cobalt single atom using ZIF-67. The cobalt single atom has high faradaic efficiency (FE) in acidic media with low onset potential, which is over 80% at 0.5 V (vs RHE). To efficiently utilize H2O2 produced by oxygen reduction reaction, additional hydrophobic layer was introduced with gas diffusion electrode (GDE) by coating poly tetra fluoro ethylene (PTFE) on catalyst layer. Additional PTFE layer on GDE confined H2O2 and CH4 together, offering higher possibilities to be reacted. In addition, liquid oxygenates generated from the reaction have hydrophilic properties that prevents further reactions by reducing the diffusion of liquid products toward cathode due to hydrophobic layer. By applying new system into flow cell, the low solubility of methane in the electrolyte can be alleviated to achieve high production rate. At last, This new system using oxygen reduction reaction to oxidize methane can make a new pathway for many chemical reaction area in the point that the system can be applied in any industrial reactions where H2O2 included.

Figure 1
(Invited) Practical Assessment of the Electrochemical Conversion of Methane to Methanol at Scale
Authors: Soucie Hanna , Elam Matthew , Mustain William Earl 
Published: November 2022

Methane is the second-most emitted greenhouse gas (GHG) globally, and it has over 25x more potency toward the GHG effect than carbon dioxide. Methane emissions in the U.S. are equally distributed across the energy, agricultural, and industrial sectors – and occur in relatively small volumes at each site, though the total volume is sizable (e.g., 145 billion cubic meters of methane coextracted with U.S. oil alone per year). To avoid its direct emission, this “waste” methane is typically flared to produce CO2. Methane flaring sites contribute to approximately 2% of global CO2 emissions. These sites represent an opportunity to convert a waste stream into desirable products. Methane (natural gas)-to-chemicals conversion units are not implemented today because of economies of scale. Because each site is relatively small, the construction of a traditional stream-reforming based gas-to-liquid plant is not economically viable. It is also not profitable to build pipelines to these sites to take the natural gas to other locations.
Recently, new concepts have been put forward for methanol production that are quoted as being more modular and possibly more profitable at smaller scales. Many of these concepts revolve around electrochemical and/or biochemical transformations. Proponents of electrochemical methane conversion have claimed that the technology will play a key role in eliminating these flare sites while opening up new business opportunities. Though this sounds very good, all of the research and development in this area remain on the bench scale as they have widely suffered from low current, high voltage losses and low faradaic efficiency. It should also be noted that there are very few studies in the literature that use economic analyses to understand the operational boundaries of a future electrochemical methane-to-methanol plant and to set realistic targets for its operation. Hence, research work is proceeding without clear operating targets in mind.
In this presentation, we will present an economic analysis on an electrochemically driven methane-to-methanol plant. We investigate a wide range of possible production rates (from 2-2000 metric tons per day), operating current densities (10-1000 mA/cm2), operating voltages (Vthermo-2.0 V) and faradaic efficiencies. This analysis also takes into consideration the cost of the electrolyzer stacks, the balance-of-plant, building sizes/layouts, labor force, etc. Over this wide design space, we determine the possible operating space that will allow for profitable operation. While doing so, we test whether electrochemical processes can economically out-compete steam reforming plants at any scale. We also identify the operating modes where electrochemical processes emit fewer greenhouse gases that traditional plants.
Pt Island Decorated Au Anode for Formic Acid Oxidation Reaction
Authors: Kim Hyunki , Ahn Sang Hyun 
Published: November 2022

For direct formic acid fuel cell (DFAFC), Pt-based catalyst is widely used as an anode. The Pt catalyst shows high activity and stability for formic acid oxidation reaction (FAOR) in acidic condition. For FAOR, it is generally accepted that Pt follows dual pathway including direct and indirect pathway. During the indirect pathway the Pt surface is vulnerable to CO poisoning, which cause the activity degradation. To enhance the CO tolerance, various Pt-based bi/ternary catalysts have been investigated. In recent, Pt–Au alloy catalysts have reported higher current density for direct FAOR pathway compared with pure Pt catalyst. The enhanced FAOR activity is originated from lower CO adsorption energy. However, the alloy structure has low catalyst utilization, which is not applicable to practical device.
In this study, we report Pt islands decorated porous Au electrode for anode of the DFAFC. The porous Au transport layer was fabricated on carbon fiber by galvanic displacement and subsequent electrochemical etching process. Using Au transport layer as a substrate, Pt self-terminated electrodeposition (SED) was performed. By adjusting the SED condition, the Pt loading and coverage on Au surface cab be easily controlled. The FAOR activity test of Pt–Au electrodes was performed by cyclic voltammetry (CV). It was revealed that the current density for direct FAOR is linearly increased as the Pt coverage on Au surface is lower. By increasing the CV cycles, the current density for direct FAOR is gradually increased owing to enhanced ensemble effect. Furthermore, the cycled electrode was applicated into practical DFAFC single cell. The single cell demonstrates more than two-order higher Pt mass activity compared with previously reported single cell using Pt–Au anode.
The Effects of Operating Conditions on the Electrode-Specific Potentials and Overall Performance of a Polymer Exchange Membrane Water Electrolyzer
Authors: Abdelrahman Mohamed Elfadil , Pasmay Fausto N , Komini Babu Siddharth , Mukundan Rangachary , Litster Shawn 
Published: November 2022

Proton exchange member water electrolysis (PEMWE) is a crucial technology for the future of clean, sustainable energy systems. However, PEMWE cells use iridium metal as the anode catalyst, which is scarce and prone to high prices and price volatility. To address this problem, researchers have investigated different methods to increase catalyst utilization, thereby reducing catalyst loading and increasing overall MEA durability. One of the governing factors of the durability of both the cathode and anode catalyst is the redox state of the metal catalyst since Pt-dissolution occurs between ~0.9 and 1 V in the acidic conditions of the cell, and IrO2 reduces to Irmetal at potentials below ~1 V which is less stable than the oxide [1]. Past research has found that hydrogen crossover is one of the leading contributors to IrOx reduction since the overall cell potential goes to 0 V when held idle for a while [2]. This study used a custom-made hydrogen reference electrode to deconvolve the electrode-specific potentials under various operating conditions. It was found that anode catalyst loading, feedwater dissolved gas concentration, and cell voltage affect the electrode-specific potentials and the overall cell performance.
[1] S. Song et al. 2008 Int J of Hydrogen Energy 2008;33:4955–61
[2] P. J. Rheinländer and J. Durst 2021 J. Electrochem. Soc. 168 024511
(Invited) Temperature Dependence of Nonradiative Transitions of an Excited Optical Ion in Solids Using the Proper Adiabatic Approximation
Authors: Collins John , Mishra Kailash C , Osborn Benjamin 
Published: November 2022

We have investigated the theory of the temperature dependence of nonradiative transitions of an optical ion in a solid from one electronic state to another using the proper adiabatic theory. The Hamiltonian, based on the nonadiabaticity operator, has been used to calculate the temperature dependence of nonradiative transition rates. The Hamiltonian, Hna

, consists of two terms, as shown in Equation 1 below.
The first term is usually used to explain nonradiative transitions of an optical ion in solids. We have shown that the first term alone leads to a zero of the transition rates at s = z for low temperature where s represents the Huang-Rhys parameter, and z relates to the energy gap between the excited state and ground state in terms of vibrational quantum of energy, hν. This zero of the transition rate cannot be removed unless the second term is included in the calculation of the transition rates on the basis of the Fermi Golden rule and the Boltzmann distribution of occupation of the vibrational states in thermal equilibrium at temperature, T, in the excited state.
Additionally, we define three functions, U1
, U2
, and U3
to describe the thermal dependence of the transition rate, corresponding to the two terms of Hna
and a cross term that appears when applying the Fermi Golden rule to calculate the transition rates. A linear combination of these three terms leads to a physically meaningful description of the temperature-dependent, nonradiative transition rate between two electronic states. These functions are used to express the temperature dependence of the quantum efficiency of a phosphor. A comparison of results from simulations and experiments will be presented.

Figure 1
(Digital Presentation) Electrochemical and Spectroscopic Studies of Bismuth(III) Compounds with L-Cysteine and L-Glutathione
Authors: Cheek Graham , Schlessman Jamie , Pena Dominik , Huang Jonathan 
Published: November 2022

Introduction
Previous research from this laboratory has involved the investigation of bismuth(III) compounds with L-cysteine1. It was found that bismuth(III) nitrate interacts extensively with L-cysteine in aqueous solutions, primarily through the strong bond between the bismuth(III) and the L-cysteine thiol group. The extent of this interaction was assessed by monitoring changes in cyclic voltammetric peak potentials, as well as UV-VIS absorption characteristics, as L-cysteine was added to the solutions. Considerable work has now been carried out on pharmaceutical medications2 such as bismuth subsalicylate (BSS) and bismuth citrate (BC) at pH 1.00 and 3.00 to simulate conditions in the human stomach, as well at pH 7.40 MOPS [(3-N-morpholino)propanesulfonic acid] to simulate general physiological conditions. In addition, studies of the cysteine-containing tripeptide glutathione have also been conducted.
Results and Discussion
By comparing results at pH 1.00 and 3.00 to those at pH 7.40 for all bismuth compounds investigated, it has been found that the extent of interaction of these compounds with added L-cysteine is much less at the lower pH levels. This conclusion was reached by noting that the absorbance of the characteristic band at 340 nm, due to the bismuth-sulfur interaction, was much lower at pH 1.00 and pH 3.00 than at pH 7.40 at corresponding levels of L-cysteine addition. Such results can be explained by the higher L-cysteine protonation state at the lower pH values compared to that at pH 7.40. This higher protonation state lessens the bismuth-sulfur interaction at the lower pH values. Interesting changes were also found in the cyclic voltammograms as L-cysteine was added in these situations. For bismuth(III) citrate (BC) at pH 7.40, a well-formed absorbance band at 320 nm was formed upon L-cysteine addition, reaching a limiting absorbance value at a 2:1 L-cysteine:BC ratio. For bismuth(III) salicylate, however, the absorbance at 300 nm to 340 nm was much lower than for BC, showing that the salicylate ligand strength is somewhat less than that for the citrate ligand under these conditions. It is also planned to present the results of similar work involving glutathione as a ligand.
References

T. Cheek and D. Peña, J. Electrochem. Soc.,
167, 155522 (2020)

Li, R. Wang, and H. Sun, Acc. Chem. Res.,
52, 216 (2019).