Amorphous-crystalline heterostructured RuMoNiN/Ni-MoO2 for highly efficient and stable alkaline hydrogen evolution reaction

The amorphization and heterostructuralization of noble metal-based materials are effective approaches to enhance the electrocatalytic performance towards the hydrogen evolution reaction (HER) in water splitting. Herein, (NH 4 ) 4 [NiH 6 Mo 6 O 24 ]·5H 2 O (NiMo 6 ) polyoxometalate was employed for the Ru combination to fabricate a heterostructured catalyst consisting of amorphous Ru MoNiN and crystalline Ni-MoO 2 (Ru MoNiN /Ni-MoO 2 ) via a simple annealing process under Ar/NH 3 atmosphere. Comprehensive structural characterizations and theoretical investigations suggest that the formation of such unique amorphous-crystalline heterostructures is governed by the application of NiMo 6 precursor and Ar/NH 3 atmosphere, which leads to the joint regulation on the electronic structure of Ru sites through -NH 2 coordination and heterostructured interaction, and thus facilitating the water dissociation and H intermediates sorption steps in the alkaline HER process. Accordingly, the as-fabricated Ru MoNiN /Ni-MoO 2 manifests excellent HER performance demanding an overpotential of only 18.3 mV at the current density of 10 mA cm −2 with a minimal overpotential decay rate of 0.62 mV h −1 during continuous operation at 1 A cm −2 . This work offers constructive suggestions for the facile construction and structural regulation of amorphous-crystalline heterostructured noble metal-based electrocatalysts for various promising energy applications.