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-2 by photocatalytic water splitting has emerged as the most promising strategy to alleviate the energy crisis. In this work, niobium pentoxide (Nb2O5)/graphitic carbon nitride (g-C3N4) type-II heterojunctions with high photocatalytic H-2 evolution rate under both visible and simulated solar light are fabricated via a novel approach involving in situ 'hydrolysis/calcination' loading of Nb2O5 nanoparticles on the g-C3N4 surface. After the optimisation, the Nb2O5/g-C3N4 heterojunctions with 5 wt% Nb2O5 content delivers high H-2 evolution rates of 2.07 +/- 0.03 and 6.77 +/- 0.12 mm of g (1) h (1) under visible and simulated solar light exposure, respectively, which are 4.1 and 4.2 times superior to those of pure g-C3N4. According to the subsequent characterisations, the effective Nb2O5/g-C3N4 heterojunction offers sufficient contact interface, which is favourable for the efficient separation of photogenerated charges. In addition, the Nb2O5/g-C3N4 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-C3N4-based hetero-photocatalysts with strong solar energy conversion capabilities. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A novel approach was developed to fabricate efficient Nb2O5/g-C3N4 heterojunctions for high-speed hydrogen evolution under visible and simulated solar light. After optimization, the heterojunctions showed a 4.1-fold and 4.2-fold increase in performance compared to pure g-C3N4 under visible and simulated solar light exposure, respectively.