Simulation Study Reveals the Role of Hydrogen Spillover in pH- and Potential-Dependent Hydrogen Evolution over the NiCu Bimetal Catalyst

Accelerating electrocatalytic water splitting via hydro-gen spillover has received increasing attention. However, the underlying mechanism of hydrogen spillover on hydrogen evolution is still ambiguous. Herein, a simulation study was carried out to determine the role of hydrogen spillover in pH-and potential-dependent hydrogen evolution over the NiCu bimetal catalyst. It was found that the current density was most prominently improved by hydrogen spillover in the neutral condition at -0.35 to -0.2 V vs reversible hydrogen electrode. By the parameter study, it was indicated that the potential and pH could improve the effect of hydrogen spillover on the current density by altering the surface reaction rates which include the hydrogen adsorption and desorption rates on the Ni and Cu particles. The pH would also affect the current density enhancement from the hydrogen spillover by the mass transfer limitation. To effectively utilize the hydrogen spillover for improved electrocatalytic hydrogen production, managing the surface reaction rate was important. Typically, the key principle was increasing the hydrogen adsorption rate of hydrogen donors and hydrogen desorption rate of hydrogen acceptors in the presence of hydrogen spillover. This fundamental understanding of hydrogen spillover contributes to the development of advanced electrocatalytic systems for hydrogen production.

Automated summary

The role of hydrogen spillover in pH- and potential-dependent hydrogen evolution over NiCu bimetal catalyst was investigated through simulation. The study found that hydrogen spillover significantly improved current density under neutral condition at specific voltage range. Furthermore, the potential and pH were shown to influence the effect of hydrogen spillover on current density by altering surface reaction rates. This understanding contributes to developing advanced electrocatalytic systems for hydrogen production.