F-doped carbon/Co3O4 composite catalyst for alkaline oxygen evolution

Electrocatalytic water splitting is a sustainable way to produce hydrogen energy. However, the oxygen evolution reaction (OER) at the anode always has sluggish kinetics and low energy conversion efficiency, which is the major bottleneck for water splitting. In this paper, the electronic structure of the Co3O4/carbon composites was regulated by anion doping. The F-doped carbon substrate is compounded with ZIF-67, and the active component Co3O4 is encapsulated in the skeleton formed by ZIF-67. The prepared hybrid nanocomposite catalyst F-Co3O4@NF has excellent OER performance. It requires an overpotential of only 172 mV with the current density of 50 mA cm-2, and the Tafel slope is 88 mV dec-1. It can maintain good stability after 24 hours of continuous operation, and the catalytic activity exceeds most of the similar series of catalysts. The characterization show that F doping can affect the catalytic activity in the form of adjusting the electronic structure and lifting d band center. These structural changes effectively optimize the adsorption/desorption capacity of the composite catalyst for hydrogen and oxygen intermediates in the catalytic process, thereby improving the catalytic activity for alkaline oxygen evolution.