Metal–Organic Framework-Based Self-Supporting Nanoparticle Arrays for Catalytic Water Splitting

Abstract

One of the efficient methods for achieving the carbon peaking and carbon neutrality goals is the generation of hydrogen from water splitting. It has been proven that reasonable nanoengineering is an important strategy to increase the performance of non-noble-metal catalysts. A metal–organic framework (MOF) is a kind of porous and versatile nanomaterial that has great potential for industrial application in water electrolysis technology. However, MOF materials are mostly powders, which greatly limits their ability to be used directly as electrode materials in practical applications. Therefore, this paper innovatively designs a general strategy to prepare controlled MOF-based three-dimensional nanoparticle-array-structured catalysts with self-support and well-orientation on the surface of nickel foam. This strategy consists of simple hydrothermal, stable stirring, and high-temperature calcination methods. In this work, the self-supporting nanoparticle-array catalyst (ZIF-67/NiCo-S/NF) is successfully prepared using 2-methylimidazole cobalt salt (ZIF-67). The special structure and composition of ZIF-67/NiCo-S/NF provide several beneficial features such as a synergistic effect, high specific surface area, fast electron transport, more exposed active sites, and enhanced electrochemical stability. At room temperature and in a 1 M KOH solution, ZIF-67/NiCo-S/NF only needs 147 and 127 mV overpotentials to obtain a current density of 10 mA cm–2 for hydrogen and oxygen evolution reactions, respectively. The excellent performance of ZIF-67/NiCo-S/NF makes it a potential industrial water-splitting catalyst for hydrogen production. This study presents a general strategy for the synthesis of self-supporting nanoparticle arrays based on the MOF, which offers a new line for the preparation of more nanoscale electrocatalysts.