CoP aerogels assisted by selenite etching as high activity electrocatalysts for water splitting

Producing Hydrogen by electrolysis of water is a sustainable renewable energy conversion method. The most important is to design and prepare high performance electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water electrolysis. Herein, aerogels of Se/CoP and Se/Fe–CoP with unique 3D porous structure have been synthesized for HER and OER, respectively, through a simple and controllable strategy of sol-gel, parkerising and doping. The catalysts of Se/CoP AGs and Se/Fe–CoP AGs served as cathode and anode have only overpotentials of 105 mV and 230 mV, and the assembled electrolytic cell by them has a voltage of 1.59 V to reach a current density of 10 mA cm−2. The mechanism of the enhanced electrocatalytic activity can be attributed to their original structure and the electronic regulation: 3D porous aerogel with high specific surface area and well–developed pore structure provides rich exposed active sites and guarantees effective ion diffusion and H2/O2 release during water splitting; the electronic modulation is achieved by selenite etching and Fe heteroatom doping to result the binding energy shift of Co to improve the catalytic performance. This work provides an effective way for the application of aerogel materials in the electrical decomposition of water.