In situ fabrication of niobium pentoxide/graphitic carbon nitride type-II heterojunctions for enhanced photocatalytic hydrogen evolution reaction.

The effective conversion of sunlight into H by photocatalytic water splitting has emerged as the most promising strategy to alleviate the energy crisis. In this work, niobium pentoxide (NbO)/graphitic carbon nitride (g-CN) type-II heterojunctions with high photocatalytic H evolution rate under both visible and simulated solar light are fabricated via a novel approach involving in situ 'hydrolysis/calcination' loading of NbO nanoparticles on the g-CN surface. After the optimisation, the NbO/g-CN heterojunctions with 5 wt% NbO content delivers high H evolution rates of 2.07 ± 0.03 and 6.77 ± 0.12 mmol g h under visible and simulated solar light exposure, respectively, which are 4.1 and 4.2 times superior to those of pure g-CN. According to the subsequent characterisations, the effective NbO/g-CN heterojunction offers sufficient contact interface, which is favourable for the efficient separation of photogenerated charges. In addition, the NbO/g-CN heterojunction possesses a large surface area, which contributes to the interfacial contact between photocatalyst and water. This work provides insights into the synthesis of novel g-CN-based hetero-photocatalysts with strong solar energy conversion capabilities.