Amorphous/crystalline NiZr heterojunction nanorods for alkaline hydrogen evolution reaction prepared by magnetron sputtering

Abstract

Design of low-cost hydrogen evolution reaction (HER) electrocatalysts with high efficiency is important for the application of hydrogen. In this work, magnetron sputtering was utilized to prepare amorphous, crystalline and amorphous/crystalline (a/c) NiZr heterostructure nanorods catalysts. With increasing sputtering power of Zr, the deposited films transformed from crystalline to a/c heterojunction and amorphous structure. Compared with its amorphous and crystalline counterparts, the a/c heterojunction presented superior performance and stability in alkaline solution. The overpotential to reach 10 mA cm^-2 and Tafel slope is low as 92 mV and 66 mV dec^-1, respectively. This is mainly due to the high intrinsic activity and electron transfer rate caused by the nanorods and a/c heterojunction structure. Density functional theory (DFT) calculations confirmed that compared with crystalline, both the water dissociation energy and hydrogen absorption energy can be lowered by forming a/c heterostructure. This work presents a method to prepare an efficient a/c heterojunction electrocatalyst via modulating magnetron sputtering conditions.