Heterointerface engineering of hierarchically assembling polyoxometalate on zinc/iron layered double hydroxide nanosheet as a remarkable bifunctional electrocatalyst for overall water splitting

The design of a low-cost, highly efficient and durable electrocatalyst is very important to accelerate the energy conversion efficiency of the electrochemical process. Herein, a simple hydrothermal synthesis of the heterostructure of Wells-Dawson polyoxometalate and zinc iron layered double hydroxide nanosheet is presented for the first time on Ni-foam (ZnFe LDH-P2Mo18/NF). The electrocatalytic activity of ZnFe LDH-P2Mo18/NF shows significantly low overpotentials of 275, 330 mV and 273, 367 mV for OER and HER to acquire a current density of 20, 50 mA cm-2 respectively. Additionally, the electrolyzer composed of ZnFe LDH-P2Mo18/NF cathode and anode shows an attractive voltage of 1.54 V to carry 10 mA cm-2. The better electrochemical performance of the ZnFe LDH-P2Mo18/NF is ascribed to the variation of electronic and chemical features, growth of electrochemically active surface area/sites because of the construction of heterointerface of Wells-Dawson polyoxometalate and zinc iron LDH. These results further demonstrate the benefits of heterointerface engineering for efficient electrolysis.

Automated summary

The design of a low-cost, highly efficient and durable electrocatalyst is crucial for improving the energy conversion efficiency of the electrochemical process. In this study, a heterostructure of Wells-Dawson polyoxometalate and zinc iron layered double hydroxide nanosheet was synthesized for the first time on Ni-foam using a simple hydrothermal method. The resulting electrocatalyst exhibited significantly low overpotentials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as well as attractive voltage in an electrolyzer.