Interstitial charge transfer pathways in a TiO2/CdIn2S4 heterojunction photocatalyst for direct conversion of sunlight into fuel

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2018, Vol.6 (33), p.16064-16073
• Main Authors: Mahadadalkar, Manjiri A, Gosavi, Suresh W, Kale, Bharat B
• Format: Article
• Language: English
• Subjects: Carrier recombination; Catalytic converters; Charge transfer; Conduction; Current carriers; Direct conversion; Electromagnetic absorption; Electronics industry; Energy; Energy efficiency; Energy levels; Flowers; Heterojunctions; Hydrogen production; Low temperature; Nanoparticles; Photocatalysis; Photocatalysts; Recombination; Solar energy; Solar energy conversion; Sunlight; Titanium dioxide
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c8ta03398f

Herein, a TiO2/CdIn2S4 nanoheterostructure photocatalyst was fabricated by a single step low temperature precipitation method. The interesting hierarchical nanostructure was obtained by in situ decoration of TiO2 nanoparticles on the surface of thin sheets of CdIn2S4 micro-flowers, which improves the light absorption capacity. The synergistic interaction between CdIn2S4 and TiO2 matrices leads to alteration in the electronic band structure of TiO2 and creates the energy levels between the conduction and valence bands. The successful formation of a ‘type II’ heterojunction in TiO2/CdIn2S4 nanoheterostructures leads to a significant improvement in photocatalytic H2 production from water (7.86 mmol h−1 g−1) under direct sunlight, which is ∼5.5 times higher than that of bare TiO2 and ∼2 times higher than that of bare CdIn2S4. The suppressed rate of photoinduced charge carrier recombination due to the enhanced interstitial charge transfer mechanism through various radiative and non-radiative pathways arising from the intimate contact between both the semiconductors leads to this improved photocatalytic performance. The appropriate selection of components endows the resultant nanoheterostructure photocatalyst with the best of both worlds. This work provides a simplistic low temperature, commercially scalable and energy efficient synthetic approach for construction of a hierarchical TiO2/CdIn2S4 nanoheterostructure with superior catalytic ability and potential for application in direct conversion of solar energy into fuel and related fields.