Synthesis of NiSe 2 /Fe 3 O 4 Nanotubes with Heteroepitaxy Configuration as a High-Efficient Oxygen Evolution Electrocatalyst.

The rational design of high-efficient non-noble metal electrocatalysts for oxygen evolution reactions (OER) is of significance in electrochemical energy conversion. However, such low-cost but highly active electrocatalysts remain poorly developed because of the daunting synthetic challenge. Here, the synthesis of NiSe 2 /Fe 3 O 4 nanotubes via a facile self-templating strategy, which manifests unique tetragonal morphology, asymmetric hollow interior, and unusual but adaptable heteroepitaxy structure, is reported. Benefiting from sufficient active sites and their improved activity around the heterointerface, accompanied by the good conductivity, the NiSe 2 /Fe 3 O 4 nanotubes exhibit as a superior OER electrocatalyst, which affords the current density of 10 mA cm -2 at a very small overpotential of 199 mV, high attainable current density beyond 200 mA cm -2 , and mass activity of 984.5 A g -1 , as well as excellent stability for 100 h in the alkaline media. This work provides a unique synthetic pathway to fabricate superior OER electrocatalysts by optimizing their composition and architecture.