Trace Iridium Engineering on Nickel Hydroxide Nanosheets as High‐active Catalyst for Overall Water Splitting

Abstract

Designing cost-effective electrocatalysts for electrochemical water splitting to generate the hydrogen energy as a future energy source is pivotal. An excellent catalyst should show high catalytic activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under different pH conditions. Here, we highlighted a high-efficient catalyst of Irdoped Ni(OH) 2 nanosheets grown on Ni foam (IrÀ Ni(OH) 2 /NF) as a high-efficient catalyst for overall water splitting in both alkaline and neutral conditions via a simple one-step hydro-thermal strategy. The optimized Ir 3 À Ni(OH) 2 /NF shows superior HER and OER activity in neutral and alkaline electrolytes. The doped Ir ions can not only serve as catalytic sites for water dissociation, but also decrease the charge density of the adjacent bridge oxygen to facilitate HER kinetics. As a result, Ir 3 À Ni(OH) 2 /NF electrolyzer exhibits superior performance of a small potential of 1.64 V under neutral condition, which is obviously lower than that of a string of recently reported neutral-pH electrocatalysts.

Universal Strategy of Bimetal Heterostructures as Superior Bifunctional Catalysts for Electrochemical Water Splitting

“…With concerns increasing in environmental issues and energy shortages, renewable energy storage and conversion have been widely explored to resolve the inevitable energy crisis. − In terms of energy current renewable technologies, electrochemical water splitting has attracted a lot of attention because it is considered as a promising approach to generate clean H 2 fuel. − Presently, plenty of efforts were devoted to exploring high-activity catalysts for improving the catalytic efficiency. − Generally, precious metals including Pt group metals and Ru group metal oxides were thought as the ideal electrocatalysts for hydrogen evolution reaction/oxygen evolution reaction (HER/OER). − Nonetheless, the scarcity and high price seriously hinder the extensive commercial applications. Thus, it is vital to design alternative electrocatalysts with the advantage of cheap and large reserves, such as transition metal carbides, , phosphides, , sulfides, , nitrides, , and oxides. , Especially for transition-metal sulfides, their inherent advantages of high stability and tunable electronic configurations enable them as promising alternatives.…”

Dual Vacancies Confined in Nickel Phosphosulfide Nanosheets Enabling Robust Overall Water Splitting

“…In particular, vacancy engineering presents a promising way to regulate the electronic structure, catalytic active sites and adsorption free energy of electrocatalysts, even in infinitesimal concentrations, realizing the significant improvement of electrocatalytic activity [17–19] . The discovery of 2D materials largely triggered increasing research interest in surface vacancy engineering towards the cost‐effective electrocatalytic hydrogen production [20–22] . At present, the majority of defect types are still restricted to single vacancy forms, such as sulfur and oxygen vacancies, optimizing the catalytic activity of various electrocatalysts for HER [23–26] .…”

Electrocatalytic Water Splitting: From Harsh and Mild Conditions to Natural Seawater

“…Moreover, the emerged Se vacancies increased the state densities near the Fermi level, thereby affecting the hydrogen adsorption energies. Tong et al [54] enhanced the overall splitting performance by doping trace amount of Ir in Ni(OH) 2 /Ni foam, in which Ir served as the active sites for water dissociation, requiring overpotentials of 43 mV at 10 mA cm -2 for HER and 350 mV at 50 mA cm -2 for OER in 1 m PBS. The overall cell voltages are 1.54 and 1.64 V at 10 mA cm -2 in alkaline and neutral conditions, respectively.…”