This project aims to develop an advanced solar energy conversion system for converting solar energy to hydrogen fuel and electric power. It aims to achieve unprecedented conversion efficiency by Integrating solar water splitting with the rechargeable battery. The solar-powered system without external bias assisted can split water and charge the battery. The significance of this project is to propose an innovative concept of efficient energy conversion and establish a promising research area of solar energy utilization.

The advantages of such a system are described as follows:

• More applicable photocatalysts: it only requires one of the band edges (conduction band or valance band) of the semiconductor catalysts to match the potential of water reduction or oxidation. More candidates with narrow bandgaps, which are usually excellent materials only limited by one band edge position, will become available in such a system. And it is adjustable to deal with different semiconductors by changing the redox couple of the flow cell.
• High utilisation of solar energy: with the application of the narrow bandgap semiconductors, a wider range of the solar spectrum will be used to drive such a system, especially the photons with long wavelength and low energy.
• Hight solar energy conversion: this advanced system eliminates the dependence on external bias and has much more theoretical efficiency than a single-junction system or conventional Z-scheme system. The redox medium inside will minimise and recycle the lost energy.

The three project objectives are:
1) Design, fabricate and characterise the membrane-based photoelectrodes and electrodes to achieve high-efficient water splitting and battery charging.
2) Design and optimise the rechargeable redox couple medium to match the band structure of photocatalysts to achieve high-efficient energy conversion.
3) Build up an advanced solar water splitting system with over 10% solar energy conversion efficiency.

Academic Supervisor:

• Dr Jian Pan
• Professor Rose Amal