Solar conversion of water into chemical energy carriers offers a sustainable alternative to fossil fuels. Inspired by natural processes, dye-sensitised photoelectrochemical cells provide a platform for H2 generation from water. Fuel-forming photocathodes are currently limited by the small range of wide-bandgap p-type semiconductors available. The majority of previous reports have employed NiO, which displays low performance with immobilised dyes and catalysts, requiring exploration of other metal oxides. In this thesis, CuCrO2 is presented as an alternative p-type semiconductor for dye-sensitised H2 production.

Synthesis and characterisation of CuCrO2 using a sol-gel method is described. First, co-immobilisation of a phosphonated diketopyrrolopyrrole dye with a Ni-bis(diphosphine) catalyst on CuCrO2 is presented as a strategy for producing a functional photocathode capable of generating H2 (Chapter 2). Photocurrent analysis and product detection revealed a high turnover number for the catalyst, outperforming an analogous NiO photoelectrode. The study serves to demonstrate the benefits of adopting delafossite structures for dye-sensitised systems. The versatility of sol-gel synthesised CuCrO2 was highlighted through immobilisation of ZnSe nanorods (NRs) (Chapter 3). Ligand-stripped ZnSe-NRs were deposited on CuCrO2 to produce the first reported ZnSe-sensitised photocathode capable of photoelectrochemical proton reduction under solar irradiation.

Hydrothermal synthesis of CuCrO2 nanoparticles enabled the development of nanostructured inverse opal electrodes (IO-CuCrO2) using a bottom-up templating method (Chapter 4). These electrodes were explored as a scaffold for solar H2 production together with a molecular Ni catalyst and two different organic dyes based on perylene monoimide and diketopyrrolopyrrole chromophores. Improved activity over the mesoporous CuCrO2 films was associated with the novel morphology of the p-SC and the integration of a more suitable dye for hole injection. Photoelectrochemical analysis and a discussion of the influence of molecular components in these highly proficient electrodes provides a basis for future development of dye-sensitised CuCrO2-based photocathodes.