Turnip-inspired BiVO4/CuSCN nanostructure with close to 100% suppression of surface recombination for solar water splitting

• Published in: Solar energy materials and solar cells 2018-10, Vol.185, p.415-424
• Main Authors: Vo, Truong-Giang, Chiu, Jian-Ming, Tai, Yian, Chiang, Chia-Ying
• Format: Article
• Language: English
• Subjects: Bismuth vanadate; Natured-inspired; Oxidation efficiency; Water splitting
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2018.05.054

Inspired by the morphologies and function of the root and the stalk of a turnip, which has evolved with the unique pattern of growth for enhancing transport phenomenon, a novel architecture of BiVO4/CuSCN architecture is fabricated on fluorine-doped tin oxide coated glass by initially fabricating bulky BiVO4 film (the root) and subsequently depositing p-type CuSCN nanorods (the stalk). With the creation of BiVO4/CuSCN nanorod heterojunction photoanodes, the photocurrent density increases to 1.78 mA cm−2 compared to 1.22 mA cm−2 of bare BiVO4 at 1.23 V vs. reversible hydrogen electrode. More importantly, the onset potential for oxygen evolution reaction exhibits a dramatic cathodic shift (~ 230 mV). The heterojunction also possesses internal quantum efficiency of approximately 50% in the range from 350 to 450 nm with relatively high solar energy conversion efficiency (0.5%) and much higher oxidation efficiency (~ 90%). The unique electrode architecture design favoring the simple water splitting process over conventionally fabricated electrode by providing more active sites and facilitates transportation and consumption of photoinduced holes could open up a new route for the high-efficiency photoanodes. A novel nature-inspired composite is designed for solar water splitting, and it reults a near-completely suppression in surface recombination and remarkably enhanced photocurrent. [Display omitted] •The design of functional material by mimicking the structural design in nature is proposed.•Novel BiVO4/CuSCN nanoarchitectures is designed for solar-driven water splitting.•BiVO4/CuSCN nanoarchitectures exhibit promising water splitting properties.•Surface recombination of photogenrated electron-hole pairs is near-complete suppressed.•Prominent charge transfer from main catalyst to hole extractor layer is identified to accelerate the redox process of OER.