Sustainable semiconductor materials and nanostructures for efficient and stable solar water splitting

Solar water splitting using photoelectrochemical (PEC) cells has emerged as one of the most promising routes to produce hydrogen as a clean and renewable fuel source. The functional semiconductor materials and efficient nanostructures are the key to realizing the green hydrogen economy. My thesis research is directed at designing and constructing sustainable semiconductor materials and nanostructures for efficient and stable solar water splitting. Firstly, I developed new functional photoelectrodes and heterogeneous composites to boost the solar water splitting, including (1) the design and fabrication of the p-type ZnPbO3 and n-type Zn2PbO4 as the new photoelectrodes for water reduction and oxidation, respectively. Additionally, it was the first time that unassisted solar water splitting was realized by combining the CoPi/Zn2PbO4 photoanode and the MoS2/ZnPbO3 photocathode. (2) the configuration of BiVO4/BiFeO3 composite with regulable polarization electric field, which achieved with synergistic ferroelectric and piezoelectric effects, accelerating the interfacial charge separation and transfer in heterojunction structure for PEC applications. Secondly, I applied various strategies to fabricate the nanostructured photoelectrodes to high performance and stability hybrid PEC systems, including (1) the novel strategy to extend the cocatalyst loading from 1D to 3D from the photoabsorbing semiconductor (PAS) in a cross-linked conducting polymer network. This scheme has been proved to greatly increase the redox reaction sites without decreasing the light absorption and effectively prohibit charge recombination. (2) in-situ growth strategy to form the intertwined nanointerfaces with uniform, continuous, fully engaged connection of the adjacent constituents. Meanwhile, the charge transfer direction has been further enforced through band structure tuning to make the photogener