A research team from the Chinese Academy of Sciences (CAS) has made a major advancement in the development of green hydrogen production technology, unveiling a novel photocatalyst that sets new performance benchmarks for titanium dioxide (TiO₂)-based water splitting systems.
Led by Professor LIU Gang of the Institute of Metal Research (IMR), the team developed a scandium (Sc)-doped TiO₂ semiconductor with a rutile crystal structure, significantly enhancing its efficiency in photocatalytic water splitting—a clean energy process that uses sunlight to separate water into hydrogen and oxygen, producing zero-emission fuel without the use of fossil fuels.
Photocatalytic water splitting has long been considered a promising pathway to green hydrogen, but its progress has been hindered by key material limitations, particularly in TiO₂. Though extensively studied, conventional TiO₂ suffers from rapid charge recombination and inefficient charge separation, limiting its practical application.
The breakthrough material developed by Prof. LIU’s team achieved an impressive apparent quantum yield (AQY) of 30.3%, and a solar-to-hydrogen (STH) efficiency of 0.34%—both record-setting figures for TiO₂-based systems operating under ambient conditions. These metrics represent the proportion of sunlight that effectively contributes to water splitting and hydrogen generation, respectively.
To overcome the traditional bottlenecks of TiO₂, the researchers used a dual-strategy approach. Scandium doping was employed to eliminate Ti³⁺ defects, which typically act as charge traps and reduce efficiency. Additionally, the team created a facet junction between the (101) and (110) crystal planes, forming a built-in electric field that directs electrons and holes to separate surfaces, thus enhancing charge separation and driving the redox reactions necessary for water splitting.
“This dual approach not only minimizes defect-induced charge recombination but also mimics the efficient charge separation mechanisms seen in photovoltaic p-n junctions,” said Prof. LIU.
The innovation holds significant promise for commercial application, particularly in China. With abundant reserves of titanium and scandium, alongside a mature industrial base for TiO₂ production and rare earth element processing, China is well-positioned to scale this technology cost-effectively.
“Our design strategy—suppressing defects and leveraging crystal anisotropy—aligns perfectly with China’s resource strengths and industrial infrastructure,” Prof. LIU added. The team’s next steps include enhancing the material’s light absorption capabilities and integrating it into scalable solar-powered hydrogen generation systems.
The findings were published in the Journal of the American Chemical Society, and the research was supported by the National Natural Science Foundation of China, the National Key R&D Program, the Science and Technology Major Project of Liaoning Province, and the CAS Projects for Young Scientists in Basic Research.
This achievement marks a pivotal step in the journey toward sustainable hydrogen energy, underscoring the Chinese Academy of Sciences’ commitment to pioneering green technologies with global impact.
