Enhancing the Understanding of Hydrogen Evolution and Oxidation Reactions on Pt(111) through Ab Initio Simulation of Electrode/Electrolyte Kinetics

Liu, Ling; Liu, Yuyang; Liu, Chungen

doi:10.1021/jacs.9b13694

“…Above simulations do not actually consider the pH effect. Even though the fundamental mechanism for HOR in alkaline solution is still under heated debate, strong experimental and computational evidence suggests that the presence of surface *OH is of great significance to enhance alkaline HOR electrocatalysis [44–47] . Hence we here also calculated the adsorption energy of *OH (Δ G OH* ) on Ni 4 Mo and pure Ni for comparison.…”

Section: Figurementioning

confidence: 99%

Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Wang

¹

,

Yang

²

,

Shi

³

et al. 2021

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Bifunctional hydrogen electrocatalysis (hydrogen‐oxidation and hydrogen‐evolution reactions) in alkaline solution is desirable but challenging. Among all available electrocatalysts, Ni‐based materials are the only non‐precious‐metal‐based candidates for alkaline hydrogen oxidation, but they generally suffer from low activity. Here, we demonstrate that properly alloying Ni with Mo could significantly promote its electrocatalytic performance. Ni4Mo alloy nanoparticles are prepared from the reduction of molybdate‐intercalated Ni(OH)2 nanosheets. The final product exhibits an apparent hydrogen‐oxidation activity exceeding that of the Pt benchmark and a record‐high mass‐specific kinetic current of 79 A g−1 at an overpotential of 50 mV. A superior hydrogen‐evolution performance is also measured in alkaline solution. These experimental data are rationalized by our theoretical simulations, which show that alloying Ni with Mo significantly weakens its hydrogen adsorption, improves the hydroxyl adsorption and decreases the reaction barrier for water formation.

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“…Based on this result, we propose that the *OH coverage on Ni 4 Mo is increased and would greatly benefit alkaline HOR. At last, growing experimental results also suggest that the reaction between surface adsorbed *OH and *H to form H 2 O is the rate‐determining step of alkaline HOR [44, 48] . To this end, we investigated the reaction kinetics by exploring the reaction barrier of water formation from CI‐NEB calculations.…”

Section: Figurementioning

confidence: 99%

“…Even though the fundamental mechanism for HOR in alkaline solution is still under heated debate, strong experimental and computational evidence suggests that the presence of surface *OH is of great significance to enhance alkaline HOR electrocatalysis. [44][45][46][47] Hence we here also calculated the adsorption energy of *OH (DG OH* ) on Ni 4 Mo and pure Ni for comparison. As shown in Figure 4 c, DG OH* is predicted to be À1.01 eV on Ni 4 Mo, which is remarkably more stable than that of pristine Ni (À0.09 eV).…”

Section: Angewandte Chemiementioning

confidence: 99%

“…At last, growing experimental results also suggest that the reaction between surface adsorbed *OH and *H to form H 2 O is the rate-determining step of alkaline HOR. [44,48] To this end, we investigated the reaction kinetics by exploring the reaction barrier of water formation from CI-NEB calculations. The barrier height is calculated to be 1.03 eV on Ni and is decreased to 0.95 eV after the introduction of Mo in Ni 4 Mo (Figure 4 e).…”

Section: Angewandte Chemiementioning

confidence: 99%

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Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Wang,

Yang,

Shi

et al. 2021

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Bifunctional hydrogen electrocatalysis (hydrogen‐oxidation and hydrogen‐evolution reactions) in alkaline solution is desirable but challenging. Among all available electrocatalysts, Ni‐based materials are the only non‐precious‐metal‐based candidates for alkaline hydrogen oxidation, but they generally suffer from low activity. Here, we demonstrate that properly alloying Ni with Mo could significantly promote its electrocatalytic performance. Ni4Mo alloy nanoparticles are prepared from the reduction of molybdate‐intercalated Ni(OH)2 nanosheets. The final product exhibits an apparent hydrogen‐oxidation activity exceeding that of the Pt benchmark and a record‐high mass‐specific kinetic current of 79 A g−1 at an overpotential of 50 mV. A superior hydrogen‐evolution performance is also measured in alkaline solution. These experimental data are rationalized by our theoretical simulations, which show that alloying Ni with Mo significantly weakens its hydrogen adsorption, improves the hydroxyl adsorption and decreases the reaction barrier for water formation.

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“…We note in passing that the atomistic origin of the pH dependence of HER remains a vividly debated topic. [260][261][262][263][264][265] With a strong understanding in atomistic modeling, high-throughput computational screening can yield predictions with high levels of accuracy for targeted experimental work and reconcile experimentally observed trends. Coupled with advanced in situ and operando characterization, these catalytic insights can be extended beyond HER to other more complex reactions such as CO 2 and N 2 reduction in the future.…”

Section: Rationalizing Experimental Her Activity With Atomistic Modmentioning

confidence: 99%

Atomistic modeling of electrocatalysis: Are we there yet?

Abidi

¹

,

Lim

²

,

Seh

³

et al. 2020

WIREs Comput Mol Sci

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Electrified interfaces play a prime role in energy technologies, from batteries and capacitors to heterogeneous electrocatalysis. The atomistic understanding and modelling of these interfaces is challenging due to the structural complexity and the presence of the electrochemical potential. Including the potential explicitly in the quantum mechanical simulations is equivalent to simulating systems with a surface charge. For realistic relationships between the potential and the surface charge (i.e., the capacity), the solvent and counter charge need to be considered. The solvent and electrolyte description are limited by the computational power: either molecules and ions are included explicitly, but the phase-space sampling is at least 10 times too small to reach convergence or implicit solvent and electrolyte descriptions are adopted which suffer from a lack of realism. Both approaches suffer from a lack of validation against directly comparable experimental data. Furthermore, the limitations of density functional theory in terms of accuracy are critical for these metal/liquid interfaces. Nevertheless, the atomistic insight in electrocatalytic interfaces allow insights with unprecedented details. The joint theoretical and experimental efforts to design non-noble hydrogen evolution catalysts are discussed as an example for the success of theory to spur and accelerate experimental discoveries.

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Enhancing the Understanding of Hydrogen Evolution and Oxidation Reactions on Pt(111) through Ab Initio Simulation of Electrode/Electrolyte Kinetics

Cited by 82 publications

References 47 publications

Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Alloying Nickel with Molybdenum Significantly Accelerates Alkaline Hydrogen Electrocatalysis

Atomistic modeling of electrocatalysis: Are we there yet?

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