Photocatalyst Z-scheme system composed of a linear conjugated polymer and BiVO4 for overall water splitting under visible light

Bai, Yang and Nakagawa, Keita and Cowan, Alexander J. and Aitchison, Catherine M. and Yamaguchi, Yuichi and Zwijnenburg, Martijn A. and Kudo, Akihiko and Sprick, Reiner Sebastian and Cooper, Andrew I. (2020) Photocatalyst Z-scheme system composed of a linear conjugated polymer and BiVO4 for overall water splitting under visible light. Journal of Materials Chemistry. A, 8 (32). pp. 16283-16290. ISSN 2050-7488

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    Abstract

    Linear conjugated polymers have potential as photocatalysts for hydrogen production from water but so far, most studies have involved non-scalable sacrificial reagents. Z-schemes comprising more than one semiconductor are a potential solution, but it is challenging to design these systems because multiple components must work together synergistically. Here, we show that a conjugated polymer photocatalyst for proton reduction can be coupled in a Z-scheme with an inorganic water oxidation photocatalyst to promote overall water splitting without any sacrificial reagents. First, a promising combination of an organic catalyst, an inorganic catalyst, and a redox mediator was identified by using high-throughput screening of a library of components. A Z-scheme system composed of P10 (homopolymer of dibenzo[b,d]thiophene sulfone)–Fe2+/Fe3+–BiVO4 was then constructed for overall water splitting under visible light irradiation. Transient absorption spectroscopy was used to assign timescales to the various steps in the photocatalytic process. While the overall solar-to-hydrogen efficiency of this first example is low, it provides proof of concept for other hybrid organic–inorganic Z-scheme architectures in the future.