A simple, rapid and scalable synthesis approach for ultra-small size transition metal selenides with efficient water oxidation performance

Transition metal-based nanomaterials are regarded as promising catalysts due to low cost and abundant reserves. In particular, transition metal-based selenide exhibit excellent capability for oxygen evolution reaction (OER). However, the currently reported synthesis approach for transition metal-based compouds are generally complicated steps, time consuming, energy-intensive and low-yield. Herein, we reported a simple, rapid and scalable microwave method for the first time and successfully synthesized a series of ultra-small size transition metal selenide nanoparticles (~5 nm in diameter) loaded on the carbon nanotube (CNT) surface. The entire reaction only takes 120 seconds and enables to obtain gram-level products. By benchmarking the OER activity, the ratio and composition optimized Ni0.27Co0.28Fe0.30Se@CNT exhibits superior water oxidation performance, requiring only 291 mV overpotential to achieve a current density of 100 mA cm-2 (48 mV smaller than the commercial RuO2), which is currently one of the most efficient transition metal-based catalysts. In addition, Ni0.27Co0.28Fe0.30Se@CNT demonstrates excellent stability up to 50 hours. This work offers a highly efficient synthesis method of ultra-small size transition metal-based selenide with outstanding catalytic performance. More profoundly, this method also pioneeres a creative synthesis avenue for other transition metal compounds, such as sulfides, phosphides, etc.