"Photocatalytic water splitting is an attractive means of efficiently converting solar energy into a storable hydrogen fuel, offering a clean and renewable source of energy that can replace fossil fuel. In this study, the Photosystem II (PSII) enzyme is employed as a biological catalyst in important proof-of-principle studies to establish the basic principles behind emerging artificial photosynthetic devices for efficient light-driven water splitting. Currently, the maximal output of PSII-based photocatalytic water splitting systems is capped by a number of factors, most significantly the non-ideal ‘wiring’ of the enzymes to the electrode giving rise to inefficient electron transfer. The present Marie Curie International Incoming Fellowship (IIF) project proposes to enhance the performance of benchmark PSII-based photocatalytic systems by ‘rewiring’ the electron transfer from the bio-catalyst to the anode to eliminate inefficient steps, and hence establish new maximal outputs achievable by such systems. This will be achieved by directed immobilisation of the PSII to the anode, followed by the inhibition of redox events in the electron flow pathway to bypass the rate-limiting step. Moreover, current photocatatlyic water splitting systems rely on expensive rare-earth components which are ultimately non-sustainable and uneconomical for use in future photocatalytic devices. In this study, newly accessible nano-structured earth-abundant substrates will be investigated as electrode material to ultimately encourage the development of more sustainable systems for photocatalytic water splitting."