Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session M45: Energy - Catalysis |
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Sponsoring Units: GERA Chair: Liang An, The Hong Kong Polytechnic University Room: Room 315 |
Wednesday, March 8, 2023 8:00AM - 8:12AM |
M45.00001: Transition Metal-based Ternary Chalcogenides as Electrocatalysts for Water-Splitting. SHANTANU SINGH, Boyang Zhao, Brent Melot, Jayakanth Ravichandran, Ahamed Maniyanganam, Billal Zayat, Germany De la Cruz, Eric McClure, Nicholas Humphrey, Shaama Sharada, Sri Narayan Hydrogen has been identified as a clean, zero carbon, sustainable, and promising energy source for the future, and electrochemical water splitting for hydrogen production is an emission-free, efficient energy conversion technology. A major limitation to this approach is the non-availability of efficient, abundant, inexpensive catalysts for water splitting. To address this issue, we explore late transition metal-based ternary sulfides, with the general formula LaMS3 (M = Mn, Fe, Co, Ni) as electrocatalysts for hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). In this work, we report synchrotron powder diffraction studies and extended x-ray absorption fine structure (EXAFS) analysis to elucidate the structure of these novel materials. Composition analysis using X-ray fluorescence spectroscopy (XRF) confirms the stoichiometric ratio of 1:1:3 for La, M, and S. These materials exhibit bifunctional catalytic activity, with overpotentials of 330-370 mV at a current density of 10 mA/cm2 for both HER and OER. These materials also show long-term stability with a negligible change in the overpotential at a constant current density of 10 mA/cm2 over 24 hours. The ability to catalyze both half-cell reactions of water electrolysis makes these materials promising candidates for bifunctional catalysts and calls for further work on these compounds to understand the catalytic mechanisms to improve their performance. |
Wednesday, March 8, 2023 8:12AM - 8:24AM Author not Attending |
M45.00002: Catalytic hydrogen production by isoelectronic doped MoS2 Artemii Ivanov, Mo Lin, Guo Xiangyu, Pengru Huang, Daria Andreeva, Kostya S Novoselov In recent years MoS2 has been widely investigated as a prospective catalyst for hydrogen production. Although MoS2 is inferior to Pt, there are plenty of ways for its modification. Manipulation with phases, amount of vacancies, edges, and grain boundaries path the way to make MoS2 a superior material for electrocatalytic H2 production. However, controlling all these parameters during the synthesis is still problematic. We claim that the isoelectronic doping during chemical vapor deposition of MoS2 may be an effective way to control these changes desirably. |
Wednesday, March 8, 2023 8:24AM - 8:36AM |
M45.00003: Importance of Mo oxidation state for efficient HER electrocatalysis: A DFT perspective to validate experiments Rafia Ahmad Designing effective, stable and cheap materials for hydrogen evolution reaction (HER) through water electrolysis could have a substantial impact on renewable energy technologies. Up to date expensive and rare metals are the most effective and benchmarks catalysts for HER, which limits their widespread use. Enormous efforts dedicated to the development of non-noble and efficient electrocatalysts for water splitting are required to tackle this problem. This has encouraged our present work where we have designed and investigated HER on an extensive range of Mo catalysts. We propose a unified designing criterion for Mo based HER catalysts based on evidences from electrochemical, physical, functional, and computational approaches on a wide range of Mo-based catalysts. We show that Mo-based HER catalysts may evolve H2 through a common pathway centered on the formation of a hydride and the underlying principle of Mo catalyst activity is the presence of the Mo3+ oxidation state. |
Wednesday, March 8, 2023 8:36AM - 8:48AM |
M45.00004: Fe doping and electrochemical reconstruction in Ni&Ni0.2Mo0.8N for large current density alkaline seawater electrolysis MINGHUI NING, Libo Wu, Yu Wang, Shaowei Song, Zhifeng Ren The industrial scale of fresh water electrolysis to produce hydrogen (H2) will make the shortage of fresh water resource even worse. Seawater, which consists of 97% of the water resource on earth, is much more abundant for water electrolysis. However, the presence of Cl−, Ca2+, and Mg2+ causes several critical problems for the seawater electrolysis. Firstly, the presence of Cl− introduces chloride oxidation reactions as the competitive reactions for oxygen evolution reaction (OER) at the anode side. The chloride oxidation reactions are undesired since the produced Cl2 or ClO− will eventually become excessive and pollutants to the environment. Even though the chloride oxidation reactions are kinetically favorable, thermodynamically unfavorable over OER. In this work, we found that Fe doped Ni&Ni0.2Mo0.8N was electrochemically reconstructed into Fe, Mo co-doped NiO as an efficient alkaline OER catalyst to thermodynamically suppress the chloride oxidation reactions. Secondly, the Cl− is corrosive to the metal substrates and catalysts like Ni, Fe metal and their alloys, causing a stability issue to the electrode. Fe doped Ni&Ni0.2Mo0.8N and Fe, Mo co-doped NiO were introduced as the anti-corrosive catalysts for the stable seawater electrolysis. Thirdly, the Ca2+ and Mg2+ will form Ca(OH)2 and Mg(OH)2 precipitates under high pH condition, which will block several critical parts of the electrolyzer. Alkaline seawater electrolyte was employed and the Ca(OH)2 and Mg(OH)2 precipitates can be quickly removed via centrifugation. In result, the HER active Fe doped Ni&Ni0.2Mo0.8N and OER active Fe, Mo codoped NiO together achieved efficient and continuous alkaline seawater electrolysis at a current density larger than 500 mA cm-2, satisfy the industrial requirement. |
Wednesday, March 8, 2023 8:48AM - 9:00AM |
M45.00005: Ternary Oxides of Pre- and Post-Transition Metals for Photocatalytic Solar-to-Hydrogen Conversion Simon Gelin, Nicole E Kirchner-Hall, Rowan R Katzbaer, Monica J Theibault, Yihuang Xiong, Matteo Cococcioni, Iurii Timrov, Quinn Campbell, Héctor D Abruña, Raymond E Schaak, Ismaila Dabo Green hydrogen produced via photocatalysis is a promising sustainable energy source. However, many of the known water-splitting photoactive semiconductors are costly or of low efficiency due to their high electronegativity which impedes the transfer of electrons from the catalyst to chemisorbed/hydrated protons. To address this issue and expand the list of known water-splitting photocatalysts, we build on previous studies [1,2] which showed via data-intensive screening that inserting pre-transition (s-block) metals in binary metal oxides can lower electronegativity while maintaining appealing light absorption properties. Starting from a family of post-transition (p-block) metal oxides used in optoelectronics, we analyze how adding pre-transition metals in these materials impacts the electronic couplings between their constituents and may improve their photocatalytic properties. Then, we screen 109 of these ternary metal oxides using band gaps and band edges predicted at both the semilocal DFT and DFT+U levels of theory. Pourbaix diagrams are also used to assess the stability of the materials in water. Based on the screening protocol, we identify seven ternary oxides among which two appear to not have been previously proposed as water-splitting photocatalysts. |
Wednesday, March 8, 2023 9:00AM - 9:12AM |
M45.00006: Pt-free Single-atom Catalysts (SACs) for the Enhanced ORR for Sustainable Hydrogen Fuel Cells Pabitra Choudhury, Naomi Helsel Atomically dispersed active sites have attracted great attention as a new frontier in the catalysis. Single-atom catalysts (SACs), well-defined mononuclear active sites, have demonstrated to be indispensable materials in catalysis. Both experimental and theoretical studies suggest that decreasing particle size is the most effective approach to improve the atom utilization and tune the physicochemical properties of these active centers, further leading to the enhancement of catalytic performances. Another advantage of the SACs is that the SACs have the ability to break away from the scaling relationship and this can lead to a high catalytic performance beyond the scaling relationship. Based on this concept, single-atom catalysts (SACs) have gained remarkable research interests due to their maximum atom utilization efficiency. Using a variety of fundamental understanding of their structure-property relations and electronic properties from density functional theory (DFT) calculations we will discuss the rational design and screen of single atom catalysts (SACs) based on low-dimensional macrocyclic molecules for the ORR catalysts for fuel cells applications. In this talk, we will also discuss a promising platinum-free cathode catalyst that effectively model the oxygen reduction reaction (ORR) of a proton-exchange membrane (PEM) fuel cell cathode better than the current commercial Pt/C catalyst has been a major shortcoming in cheaper fuel cell technology. Overall, the promising platinum-free cathode catalyst must offer great ORR activity, ORR selectivity, and acid stability will also be discussed. |
Wednesday, March 8, 2023 9:12AM - 9:24AM |
M45.00007: Chiral topological semimetal PdGa with giant spin-split Fermi-arc for oxygen reduction reaction XIA WANG Oxygen reduction reaction (ORR) hold the vital role for the clean energy technologies, such as fuel cells and metal-air batteries. It starts with paramagnetic oxygen molecular in a triplet ground state and generates with diamagnetic intermediates that are all in singlet states. Both electron transfer and orbital interactions between the catalyst and the intermediate show spin-dependent character, making the reaction kinetics and thermodynamics sensitive to the spin configurations. Hence, we synthesized high-quality topological single crystals of PdGa that naturally hosts the chiral geometry. The intrinsic chiral structure associated with and long Fermi arc facilitate the electron transfer in ORR. Moreover, the topologically protected surface states originating from the d orbitals of the surface Pd atoms could weaken the oxygen intermediate adsorption strength, thus intrinsically boosting the ORR kinetics. Our work provides a new approach to design highly efficient oxygen catalysts by introducing the topological chiral order in the materials. |
Wednesday, March 8, 2023 9:24AM - 9:36AM |
M45.00008: Transient characteristics of a solid oxide electrolysis cell under intermittent power-supply conditions Zhaojian Liang, Peixin Dong Solid oxide electrolysis cell (SOEC) is a promising electrochemistry device to produce hydrogen from intermittent renewable power sources. To provide a quantitative understanding of the transient characteristics of SOEC, especially under fluctuating power-supply conditions, a numerical 3-D transient simulation is conducted in this study. Through the analysis on the electrical, molar, and thermal responses of SOEC to voltage ramps with different ramp rates and ramp magnitudes, it is found that the discrepancies in transfer rates – electronic/ionic > mass > heat – lead to the electrical undershoots or overshoots after fast voltage changes. A quantitative analysis from linear time-invariant systems shows that the electrical responses of SOEC are governed by two time constants (related to mass transfer and heat transfer) in the functional layer. Based on the acquired time constants, control strategies on dynamic responses of SOEC are discussed. Slowing down the voltage ramp is effective in alleviating the current overshoots induced by mass-transfer lag but ineffective in those induced by heat-transfer lag. In addition, spatial factors, such as the rib and the length of channel, also have significant impacts on the electrical responses, e.g., inducing non-uniform electrical responses in the functional layer. The results of this study are essential for the design and dynamic control of SOEC. |
Wednesday, March 8, 2023 9:36AM - 9:48AM |
M45.00009: Continuum Modeling of Metal-Insulator-Semiconductor Photoelectrodes Alex J King, Adam Z Weber, Alexis T Bell Metal-insulator-semiconductor (MIS) photoelectrodes are commonly used in solar-to-chemical energy conversion because of their high catalytic activity and stability. The metal catalyst has lower kinetic overpotentials than the bare semiconductor surface at the same current density. An ultrathin insulator layer helps to protect the semiconductor from electrolyte corrosion and to enhance photovoltage. While previous work has explored the influence of insulator properties on photoelectrochemical (PEC) performance, there is a lack of understanding of how these properties fundamentally impact photovoltage and subsequent fuel-formation rates. Continuum modeling is uniquely suited to elucidate the phenomena leading to enhanced performance and to identify the insulator properties needed for optimal performance. |
Wednesday, March 8, 2023 9:48AM - 10:00AM |
M45.00010: Theory guided screening of catalyst materials for hydrogen production from methane via plasma-catalysis Jagannath S Mantha, Graeme Henkelman Natural gas which mainly consists of Methane (CH4) is a major byproduct in oil drilling. Since it’s hard to store CH4, methane flaring is a common practice in the petroleum industry. Production of hydrogen (H2) gas from CH4 is a viable alternative to deal with excess CH4 if we can safely manage solid carbon byproduct without poisoning the catalyst surface. Conventional processes to activate CH4 require extreme temperatures and pressures. In this work we propose plasma-catalytic conversion of CH4 directly to H2 gas and solid carbon, which can be done at ambient pressures and lower temperatures due to plasma activation (plasma generated from renewable electricity). Non-thermal plasma pushes reactants to excited states (non-equilibrium) which breaks scaling relationships of CH4 activation. This allows us to easily activate CH4 on metals which bind to C weakly. Weak C binding energy makes it easier to manage coke formation effectively without catalyst poisoning. In this work, we used density functional theory and nudged elastic band calculations to get micro-kinetic models from which theoretical turnover frequencies (TOF) are calculated (with and without plasma) for various transition metal catalysts. Our preliminary calculations show that transition metals like Co & Ir have several orders of magnitude improvement in TOF with the plasma activation. Going forward our experimental collaborators will use our computational results to choose appropriate catalyst candidates. |
Wednesday, March 8, 2023 10:00AM - 10:12AM |
M45.00011: Extended Born-Haber cycle for explaining oxygen-chlorine chemisorption scaling on transition metals Robert B Wexler, Emily A Carter We study a wide range of transition metals and characterize how they bind O and Cl. We found strong correlations between O-Cl chemisorption enthalpies on the surfaces of elemental 3d transition metals, Pd, and Pt, which previously had been shown only for one family of transition metal alloys and binary rutile metal oxides. We first show – using density functional theory (DFT) with various exchange-correlation (XC) functionals and van der Waals (vdW) corrections – that the vdW-uncorrected XC functional based on the generalized gradient approximation of Perdew, Burke, and Ernzerhof (PBE) most accurately reproduces the measured chemisorption energies of O and H on the (111) surface of face-centered-cubic (fcc) Pt. We then, using DFT-PBE, reveal the presence of O-Cl chemisorption scaling relations on surfaces of the 3d transition metals, Pd, and Pt in the fcc and their ground-state bulk crystal structures, indicating that the electronic structure of the metals, rather than any morphological contribution, largely dictates the adsorption properties of these ionic adsorbates. Furthermore, we identified that the O chemisorption energy could be modeled accurately using an extended Born-Haber cycle based on the sum of the first and second ionization energies of the relevant metal atoms. Finally, we synthesize these results in the context of O-Cl chemisorption scaling on transition metal alloys and rutile metal oxides, showing that the differences in the intercepts of their linear scaling relations can be attributed primarily to differences in work functions between metals and metal oxides. |
Wednesday, March 8, 2023 10:12AM - 10:24AM |
M45.00012: Material Design Considerations for Bipolar Membranes in Energy Conversion Justin Bui, Adam Z Weber, Alexis T Bell Bipolar membranes (BPMs), which consist of a catalyst layer (CL) sandwiched between a cation-exchange membrane (CEM) and an anion-exchange membrane (AEM), possess significant potential for application in energy conversion due to their ability to convert electrical energy into pH gradients by accelerating water dissociation (WD) within their catalytic interface. Unfortunately, the mechanism of WD, and the electrochemical behavior of BPMs, are poorly understood. Advancing understanding of BPM performance is critical to their deployment. |
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