Hydrogen energyProject Efficient Solar Hydrogen Generation
This final knowledge sharing report discusses how the project successfully developed robust integrated stand-alone systems achieving 20% solar-to-hydrogen (STH) conversion efficiency at ambient conditions using low-cost materials.
Direct solar-to-hydrogen generation is a promising approach for producing low-cost renewable hydrogen since the energy from the sun can be used to directly drive the water splitting redox reactions, eliminating the need for separate power generation and electrolyser systems, as well as complex power infrastructure and additional balance of plant. However, the systems demonstrated so far either require expensive materials or present low solar-to-hydrogen (STH) conversion efficiencies – both of which increase the levelised cost of hydrogen (LCOH). The aim of this project is to design, fabricate and integrate low-cost semiconductors and catalysts for direct solar-to-hydrogen production systems. Achieving a high STH conversion efficiency based on durable low-cost materials is crucial to promote commercial adoption of solar hydrogen systems. When two semiconductors with complementary light absorption abilities (i.e., one absorbing the blue part and the other absorbing the red part of the solar spectrum) are configured in tandem, they could exploit a larger fraction of the solar spectrum, providing high STH efficiencies necessary for practical implementation. Perovskite and Si are low-cost semiconductors suitable to construct tandem cells for carrying out direct solar hydrogen production at high efficiencies when integrated with Ni-based catalysts. The project investigated the design and development of robust integrated solar-driven water splitting systems and achieved a record 20% STH conversion efficiency at ambient conditions using all low-cost materials (perovskite/Si tandem cell and Ni-based catalysts). The development of efficient solar water splitting systems using all low-cost materials is expected to considerably accelerate the commercialization of this promising technology, leading to reduction in the cost of green hydrogen.