The use of hydrogen as a fuel, when generated from water using semiconductor photocatalysts and driven by sunlight, is a sustainable alternative to fossil fuels. Polymeric photocatalysts are based on Earth-abundant elements and have the advantage over their inorganic counterparts in that their electronic properties are easily tuneable through molecular engineering. Polymeric photocatalysts have developed rapidly over the past decade, resulting in the discovery of many active materials. However, our understanding of the key properties underlying their photoinitiated redox processes has not kept pace, and this impedes further progress to generate cost-competitive technologies. Here, we discuss state-of-the-art polymeric photocatalysts and our microscopic understanding of their activities. We conclude with a discussion of five outstanding challenges in this field: non-standardized reporting of activities, limited photochemical stability, insufficient knowledge of reaction mechanisms, balancing charge carrier lifetimes with catalysis timescales and the use of unsustainable sacrificial reagents.
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Y.W. acknowledges the China Scholarship Council (CSC) for full PhD studentship. The UK Engineering and Physical Sciences Research Council (EPSRC) is acknowledged for funding through grant EP/N004884/1 (for R.S.S., L.W., M.A.Z. and A.I.C.). This work has received funding from the European Union’s Horizon 2020 research and innovation programme (Marie Skłodowska-Curie Individual Fellowship to A.V.) under grant agreement no. 796322. M.S. thanks the Imperial College President’s PhD Scholarship scheme. R.G. thanks the Fonds de recherche du Québec—Nature et technologies (FRQNT) for postdoctoral support and the University of British Columbia for start-up funds. J.R.D. acknowledges support from ERC AdG Intersolar (291482). Y.W., S.J.A.M. and J.T. acknowledge the financial supports from UK EPSRC (EP/N009533/1), Royal Society Newton Advanced Fellowship grant (NA170422) and the Leverhulme Trust (RPG-2017-122).
The authors declare no competing interests.
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Wang, Y., Vogel, A., Sachs, M. et al. Current understanding and challenges of solar-driven hydrogen generation using polymeric photocatalysts. Nat Energy 4, 746–760 (2019). https://doi.org/10.1038/s41560-019-0456-5
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