Interfacial assembly of photosystem II on nanotubular V2O5/TiO2 for photocurrent generation

Abstract

Photosystem II (PSII) as a membrane protein in natural photosynthesis possesses the key capacity of water splitting under light irradiation. Recently, PSII has been investigated in the semi-artificial photo-bioelectrochemical systems for solar energy conversion, and the conversion efficiency is greatly affected by the electronic communication between the PSII and the electrode. Here, a semi-artificial photoanode system was fabricated by the interfacial assembly of PSII on the ITO electrode modified by the nanotubular V2O5/TiO2 composite material synthesized through layer-by-layer self-assembly process and sol–gel method using cellulosic filter paper as template. This hybrid photoanode exhibits obviously improved photocurrent responses, compared with the PSII photoanode without electrode surface modification and the hybrid PSII/V2O5, PSII/TiO2 photoanodes. Particularly, the direct electron transfer photocurrent with higher stability is nearly 19 times that of the PSII photoanode. And a further 17-fold increase is shown in the mediated electron transfer photocurrent test. The enhanced photoelectric conversion properties of this hybrid PSII-based photoanode could be beneficial from the three-dimensional hierarchical microstructure of V2O5/TiO2 composite that promotes the protein immobilization, as well as the matched band energy that forms a cascaded electron transfer. This work may open a new route for the construction of advanced solar energy conversion systems based on photoactive PSII combined with artificial metal oxide and other semiconductor nanomaterials.