In-Situ Generated Trimetallic Molybdate Nanoflowers on Ni Foam Assisted with Microwave for Highly Enhanced Oxygen Evolution Reaction

Chemistry. 2021 Jun 21;27(35):9044-9053. doi: 10.1002/chem.202100278. Epub 2021 May 19.

Abstract

Oxygen evolution reaction (OER) is considered as a critical half-cell reaction of water splitting, the kinetics of which is sluggish even not favored, thus requiring highly active electrocatalysts to shrink the reaction energy barrier and improve the energy conversion efficiency. In this study, In-situ generated trimetallic molybdate nanoflowers on Ni foam by a straightforward and time-saving solvothermal method assisted with microwave, not only bring synergistic effect into full play between multiple metals, but also construct a well-defined nanoflower-like structure accompanied by larger specific area (273.3 m2 g-1 ) and smaller size than the pristine NiMoO4 . The resulting Ni0.9 Al0.1 MoO4 -NF requires a relatively low overpotential of 266 mV for OER at 10 mA cm-2 , which outperforms commercial RuO2 catalysts (274 mV). Such excellent performance compares favorably to most previously reported NiMoO4 -based electrocatalysts for OER. This work not only supplies a facile method to construct a well-defined nanoflower-like structure on foam, but also broadens our horizons into the mechanism of OER in alkaline conditions.

Keywords: In-situ; Microwave; Nanoflower; NiMoO4; OER.