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China makes new breakthroughs in using light to split water for hydrogen production. Source: Xinhua Net, April 9, 2025. 150 years ago, the science fiction master Jules Verne predicted that water would become the ultimate fuel of the future. Today, scientists are working to turn this fantasy into reality. Liu Gang, director of the Institute of Metal Research at the Chinese Academy of Sciences and head of the research team, said that Chinese research teams have made breakthrough advances recently in the field of \"photocatalytic water splitting for hydrogen production\": by \"structural modification\" and \"element substitution\" of the semiconductor photocatalytic material titanium dioxide, the efficiency of producing hydrogen through the direct splitting of water using sunlight has been significantly improved. The relevant findings were published on April 8 in the Journal of the American Chemical Society. Currently, there are mainly two methods for producing hydrogen from solar energy: one is to generate electricity using solar cells and then electrolyze water; this method is efficient, but the equipment required is complex and expensive ； The second method is the direct photolysis of water by sunlight: water molecules are “broken down” with just one step using semiconductor materials such as titanium dioxide under sunlight. Liu Gang’s team focuses primarily on the second technical approach. It is said that there are serious obstacles to using traditional titanium dioxide for water splitting: when light shines on titanium dioxide, charged particles (electrons and holes) are generated within it, and these charged particles serve as the \"tools\" for splitting water. However, these activated electrons and holes are not stable. “Electrons and holes are like race cars that have lost their direction, racing around inside materials that resemble mazes; the vast majority of them recombine and annihilate within one millionth of a second. Furthermore, the high-temperature preparation environment tends to cause oxygen atoms to \"escape,\" resulting in the formation of oxygen vacancies that capture electrons; all of these factors significantly reduce the efficiency of photocatalytic reactions. ”Liu Gang said. The research team creatively introduced scandium (Sc), the neighbor of titanium in the periodic table, to modify titanium dioxide. Experience has shown that scandium possesses three key advantages: first, the radius of scandium ions is similar to that of titanium, allowing them to fit perfectly into its lattice without causing structural deformation ； Second, the stable valence state of scandium happens to be able to neutralize the charge imbalance caused by oxygen vacancies ； Thirdly, scandium ions can restructure the crystal surface to create specific crystal face structures, acting like \"charge highways and overpasses\" that allow electrons and holes to move smoothly out of the maze. Through precise control, the team successfully developed a titanium dioxide material with significantly improved performance; its ultraviolet utilization rate exceeded 30%, and its hydrogen production efficiency under simulated sunlight was 15 times higher than that of similar materials, setting a new record for this material class. Liu Gang said, “If a 1-square-meter photocatalytic panel is made from this material, it can produce about 10 liters of hydrogen per day under sunlight.” ” Researchers explain that titanium dioxide, as an inorganic material with wide industrial applications, has a production capacity in China that accounts for over 50% of the global total; a complete industrial chain has been established for its production. China also ranks among the top countries in terms of reserves of rare earth elements such as scandium, which gives it significant industrial advantages for the further development and industrial use of photocatalytic materials. Further improvements in the efficiency of photocatalytic water splitting hold the promise of enabling industrial applications and facilitating the upgrading of the energy structure.