A Highly Active and Durable Hierarchical Electrocatalyst for Large-Current-Density Water Splitting.

Dong, Yan; Deng, Zhiping; Zhang, Hao; Liu, Guangyi; Wang, Xiaolei · Nano Lett · 2023

basic_science · Level V

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Abstract

Designing bifunctional catalysts with high current densities under industrial circumstances is crucial to propelling hydrogen energy with a boost from fundamental to practical application. In this work, heterojunction nanowire arrays consisting of manganese oxide and cobalt phosphide (denoted as MnO-CoP/NF) are designed to meet the industrial demand by regulating the synergic mass transport and electronic structure coupling with numerous nano-heterogeneous interfaces. The optimal MnO-CoP/NF electrode exhibits remarkable bifunctional electrocatalytic performance with overpotentials of 259.5 mV for hydrogen evolution at a large current density of 1000 mA cm<sup>-2</sup> and 392.2 mV for oxygen evolution at 1500 mA cm<sup>-2</sup>. Moreover, the MnO-CoP/NF electrode demonstrates superior durability and an ultralow voltage of 1.76 V at 500 mA cm<sup>-2</sup>, outperforming that of a commercial RuO<sub>2</sub>||Pt/C electrode. This work sheds light on the design of metallic heterostructures with optimized interfacial electronic structures and a high abundance of active sites for practical industrial water splitting applications.