CoMo carbide/nitride from bimetallic MOF precursors for enhanced OER performance

The rational design and facile synthesis of transition metal-based catalysts supported by carbon nanomaterials with high activity, selectivity and stability remain a great challenge. Recently, the low-cost, stable and high-performance electrocatalysts for efficient oxygen evolution reaction (OER) derived from porous metal-organic framework (MOF) precursors have attracted numerous attention. Herein, a new type of CoMo carbide/nitride embedded in the flower-like carbon materials (CoMo-MI-T, MI = 2-Methylimidazole, T = 400, 500, 600, 700 degrees C) has been synthesized by a simple pyrolysis, in which bimetallic CoMo-MI precursors can be conveniently converted from crystalline cobalt-based MOFs of Co-MI by solvothermal reaction. The pyrolyzed CoMo-MI-T series exhibits a hierarchically porous nanostructure, high Co3Mo3C/N content, suitable N-doping, graphitic carbon layers as well as well-preserved flower-shaped morphology, which shows an excellent OER performance. Among them, the most optimal CoMo-MI-600 owns the small overpotential of 316 mV at 10 mA cm(-2) and Tafel slope of 89.9 mV dec(-1) in 1.0 M KOH solution. Meanwhile, the rotating ring-disk electrode technique is examined to verify near 4-electron transfer process for CoMo-MI-600 together with a high Faradaic efficiency of 98.7%. The well-performed CoMo-MI-600 electrocatalyst may be stemmed from the best balance of the synergistic effect of abundant multi-component, suitable electrical conductivity and large porosity. The current work will provide a new route to prepare MOF-derived bimetallic active sites in porous carbon nanomaterials with satisfactory activity and robust stability in the relevant energy applications. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study successfully synthesized a new type of CoMo carbide/nitride electrocatalyst using a simple pyrolysis method, showing excellent performance in the oxygen evolution reaction in a 1.0M KOH solution.