In situ formation of NbOx@NbN microcomposites: seeking potential in photocatalytic and Li-ion battery applications

Abstract

NbO_x@NbN microcomposite particles with enhanced photocatalytic and electrochemical properties were synthesized through in situ partial oxidation from a NbN precursor by annealing in air. Thermal treatment optimization is carried out accompanied by extensive investigation on the formation of NbO_x with TEM and XPS analysis. The as-prepared NbO_x@NbN composite inherited the layer-like structure from the pre-annealed NbN powders and grew with mixed niobium oxides. The sample exhibited a 17-fold increase in photocatalytic hydrogen production and a 1.8 times enhancement of the specific capacity as an anode material for lithium-ion batteries compared with commercial Nb₂O₅. An illustrative scheme of the sample formation and photo-driven reaction was proposed. Due to the escape of nitrogen during heating, the mesopore-containing microstructure and increased specific surface areas are advantageous for electron mobility and interfacial reactions. By analyzing the positive effect of the optical and electrical properties from NbO_x and the improved light absorption from the presence of NbN, the functional properties of the NbO_x@NbN heterostructure in terms of both photocatalytic and electrochemical applications are revealed for the first time.