First-Principles-Based Kinetic Monte Carlo Model of Hydrogen Evolution Reaction under Realistic Conditions: Solvent, Hydrogen Coverage and Electric Field Effects

Abstract

The hydrogen evolution reaction (HER) plays an important role in electrocatalytic water splitting. Despite the progress on the development of HER catalysts, the dynamic evolution of HER reaction under realistic electrochemical conditions considering the electric field, solvent, and hydrogen coverage effects is still unclear. In this study, a first-principles-based H surface coverage and potential-dependent kinetic Monte Carlo (KMC) HER model on the Pt (111)/Pt (100) surface is presented. The reaction kinetics and electronic structure analysis of HER on Pt surfaces in the presence of dihydrated proton (H 5 O 2 + ) and H surface coverage is investigated using density functional theory (DFT). The HER KMC model was developed based on the DFT-calculated energetics. The KMC simulation results showed that consideration of H 5 O 2 + species and dynamic evolution of H coverage is essential for accurate description of HER reaction on the Pt catalyst, which fits well with HER polarization data. Moreover, sensitivity analysis shows that HER on Pt ( 111) is mainly affected by the Tafel step. On the Pt(100) surface, HER is primarily governed by the Heyrovsky pathway. Surface species evolution analysis demonstrates that the high working potential accelerated the formation of [Pt-2H] species, leading to increased H coverage and accelerating the HER process. The predicted weakened H binding strength and increased H coverage at high HER working potential was verified by in situ attenuated total reflection Fourier transformed infrared spectroscopy analysis. Overall, the proposed DFT-KMC model represents the state-of-art dynamic simulation of catalytic HER reaction, providing important insights into the evolution of HER under realistic operation conditions.

Ru doping and interface engineering synergistically boost the electrocatalytic performance of a WP/WP2 nanosheet array for an efficient hydrogen evolution reaction

“…In addition, the Δ G H* value of H adsorption on pure WP/WP 2 double W sites is −0.272 eV, which indicates that metal Ru doping can also balance the competition between H adsorption and desorption processes, making the Δ G H* value closer to zero, which will be a very favorable condition for HER. Generally speaking, a very high Δ G H* value indicates that the adsorption capacity of H is relatively weak, which makes it difficult to adsorb H on the surface of the catalyst, which is not conducive to the occurrence of HER, while a very low Δ G H* value means that H will be tightly adsorbed on the surface of the catalyst, which seriously limits the desorption of H and the precipitation of H 2 , 50 suggesting that Ru-WP/WP 2 NH/CC has outstanding HER activity. According to the d-band theory, the d-band center ( ε d ) can effectively describe the binding strength between the adsorbed H and the catalyst surface.…”

The oxygen evolution reaction on cobalt atom embedded nitrogen doped graphene electrocatalysts: a density functional theory study

“…Setting U to 0 V here could provide information on the intrinsic activity of the catalysts in the absence of applied potentials. 29,30 The free energy changes (Δ G ) relative to an initial state can be obtained by the energy difference between products and reactants at every step in the OER. The thermodynamic catalytic activity of the OER was evaluated by examining their η OER , calculated from the following eqn (7): η OER = max(Δ G 1 ,Δ G 2 ,Δ G 3 ,Δ G 4 )/ e − 0.4010where Δ G 1–4 refers to the free energy changes of reaction via eqn (5a)–(5d), and 0.4010 eV is the standard reduction potential of eqn (3).…”

Combination of Co Single Atom and MoS2 Antisite Defect for Efficient Electrocatalytic CO2 Methanation: A Rational Design at Electronic Scale

“…where e represents the electron transferred during the elementary reaction (e = 1 in this work). To investigate the effect of temperature and applied potential on the reaction rate, the constants of reaction rate (k) are obtained by, [47] k¼ k B T h…”