Scale-up synthesis of amorphous Ni-Fe tungstate for highly-efficient oxygen evolution reaction

NiFe-based materials have been widely explored as electrocatalysts for the oxygen evolution reaction (OER). However, it remains a challenging task to simultaneously improve their catalytic performance, stability, and feasibility of scale-up production. Herein, a microimpinging stream reactor (MISR) is constructed for the scale-up synthesis of amorphous Ni-Fe tungstate (NiFeWO₄-3) powder as an active OER electrocatalyst. NiFeWO₄-3 delivers a low overpotential of 235 mV at 10 mA cm^-2 with a Tafel slope of 42 mV dec^-1, as well as a good stability for 110 h long-term operation at a high current density of 290 mA cm^-2, far surpassing the Ni-Fe oxide (NiFeO-3) catalyst and previously-reported NiFe-based powders. Experiments and density functional theory (DFT) calculation analysis indicate that the high-valence W⁶⁺ not only induces the generation of amorphous structures but also modulates the electronic configuration of NiFeWO₄-3 and optimizes the adsorption of key intermediates, hence remarkably boosting its OER performance.