Researchers from the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing at Wuhan University of Technology, led by Professor Xiaojie Liu, have made significant strides in improving the efficiency of solar water splitting for hydrogen production. Their work focuses on enhancing the performance of photocatalysts, which are materials that use sunlight to drive chemical reactions, such as splitting water into hydrogen and oxygen. The study, titled “Mechanistic Insights into Water-Splitting, Proton Migration, and Hydrogen Evolution Reaction in g-C3N4/TiO2-B and Li-F co-doped Heterostructures,” was published in the journal Applied Catalysis B: Environmental.
The team strategically designed a heterostructure combining graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2-B), and further enhanced its performance through lithium and fluorine co-doping. This approach significantly improved the photocatalytic hydrogen evolution efficiency of the system. The researchers systematically studied the decomposition of water molecules on the heterostructure’s surface, the migration and diffusion of protons across the interface, and the overall hydrogen evolution performance.
Their findings revealed that the heterojunction surface exhibits a low energy barrier for water decomposition, facilitating both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Proton transfer occurs preferentially from the TiO2-B surface to the g-C3N4 surface through the interface. The presence of polar covalent bonds creates a substantial energy barrier for proton migration from the TiO2-B surface to the interface, acting as a rate-determining factor in the hydrogen evolution process. However, the formation of hydrogen bonds significantly reduces the migration energy barrier for protons crossing the interface to the g-C3N4 surface.
The researchers also analyzed the hydrogen adsorption free energy and found that the heterojunction surface exhibits optimal proton adsorption and desorption characteristics. The synergistic combination of low water decomposition energy barrier, reduced proton migration energy barriers, and exceptional HER performance makes both the g-C3N4/TiO2-B heterostructure and the Li-F co-doped g-C3N4/TiO2-B heterojunction promising candidates for efficient photocatalytic hydrogen evolution.
For the energy sector, this research offers a pathway to develop more efficient photocatalysts for solar water splitting, a process that can produce clean hydrogen fuel using renewable energy sources. The practical applications of this work could contribute to the advancement of hydrogen production technologies, supporting the transition towards a more sustainable and low-carbon energy future.
This article is based on research available at arXiv.