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

Abstract

Accelerating electrocatalytic water splitting via hydrogen 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.

Hydrophobic Surface Modification of Cu-Based Catalysts for Enhanced Semihydrogenation of Acetylene in Excess Ethylene

“…In contrast, when mixed with Cu 2 O-C 16 R, WO 3 underwent visible reduction, signifying a hydrogen spillover. This observed hydrogen spillover in the catalyst aligns with prior reports on PdCu and NiCu alloys, where hydrogen activation occurs on species with robust hydrogen dissociation capabilities, subsequently overflowing to secondary active sites for hydrogenation. ,, …”

“…This observed hydrogen spillover in the catalyst aligns with prior reports on PdCu and NiCu alloys, where hydrogen activation occurs on species with robust hydrogen dissociation capabilities, subsequently overflowing to secondary active sites for hydrogenation. 12,44,45 Based on the aforementioned findings, a plausible mechanism is proposed as follows. In the hydrogenation process of Cu 2 O-C 16 , acetylene interacts with surface Cu + to yield Cu 2 C 2 , which subsequently undergoes disproportionation into CuC x and Cu under a hydrogen atmosphere.…”

Hydrogen Spillover in Electrochemical Hydrogen Evolution Reaction

“…Through simulation studies, Zheng et al found that pH and potential can change the surface reaction rate of Ni and Cu particles in NiCu, while pH affected mass transfer limitations, resulting in changes in current density for hydrogen spillover. [9] A number of experimental approaches have been reported to detect hydrogen spillover during electrocatalysis in order to better study this phenomenon. For example, hydrogen spillover from WO 3 has been extensively studied recently.…”

“…[8] More specifically, the hydrogen protons adsorb at the hydrogen-rich site (usually metals) with relatively stronger hydrogen adsorption energy and then migrate or diffuse through the interface to the hydrogen-poor site, which is the support surface with relatively weaker hydrogen adsorption energy. [9] For general HER on single active sites, the proton adsorption step or hydrogen desorption would be determined by the single G H of the sites, however, the hydrogen spillover effect depends on the characteristics of metal and support, allowing the multiple sites with different G H to kinetically promotes adsorption/desorption processes. To date, many successful studies on hydrogen spillover-based binary-component catalysts have been identified, which have led to superior activities to the commercial Pt/C catalysts.…”

Near-Infrared-Responsive Photocatalytic CO2 Conversion via In Situ Generated Co3O4/Cu2O

“…Solar-driven conversion of CO 2 to fuel is a promising and feasible approach for addressing the threats of both energy crisis and climate change. − In recent years, tremendous efforts have been devoted to developing various technologies for the utilization of sunlight and CO 2 reduction (CO 2 RR) systems. − The commonly studied solar-powered CO 2 reduction systems involve photocatalytic systems, photovoltaic–electrochemical (PV–EC) systems, photoelectrochemical (PEC) systems, and solar thermochemical systems. , Among these, photocatalytic reduction of CO 2 and H 2 O to produce fuels enabling the use of direct sunlight as a source of energy , is often regarded as a promising technology. − However, the efficiency of photocatalytic CO 2 reduction is still far behind the requirement for industrial applications. , One of the reasons is insufficient solar energy utilization. Most of the commonly used photocatalysts can only utilize the ultraviolet–visible (UV–vis) band of the solar spectrum, while the infrared band (ca.…”