Interfacial engineering regulated by CeO to boost efficiently alkaline overall water splitting and acidic hydrogen evolution reaction

Abstract

• CeO x can regulate electronic structure and increase oxygen vacancies concentration. • MoO 2 and CeO x heterojunction can enhance the intrinsic activities and stability. • MoO 2 CeO x /NF shows both better HER activity than Pt/C and better OER activity than RuO 2 in alkaline solution, and at the same time can achieve superior HER activity in acidic condition. • DFT calculations confirm that hetero-interfaces can increase the conductivity. Development of a low-cost and durable bifunctional electrocatalyst with high catalytic activity by hybridizing rare earth metal and non-noble metal is of utmost significance. Herein, a bifunctional electrocatalyst consisting of MoO 2 and CeO x heterostructure is synthesized via interfacial engineering. Particularly, due to its unique hetero-interface with abundant oxygen vacancies, the MoO 2 -CeO x /NF is able to exhibit outstanding hydrogen evolution reaction (HER) performance with an overpotential of 26 mV at 10 mA cm −2 , and a preferable oxygen evolution reaction (OER) overpotential of 272 mV at 100 mA cm −2 in 1 M KOH. The recorded HER and OER overpotentials of MoO 2 -CeO x /NF are clearly smaller than those of Pt/C (HER overpotential of 27 mV) and RuO 2 (OER overpotential of 393 mV) at the same current density. More importantly, MoO 2 -CeO x /NF can also exhibit good HER activity with an overpotential of 50 mV at 10 mA cm −2 in acidic media. Thus, it is expected that this work can offer a new approach in the realization of high-catalytic alkaline overall water splitting and acidic HER performance through the rational design of rare-earth metal and non-noble metal heterostructure.