A recent breakthrough in the field of solar energy has emerged from a Chinese research team, known for their previous development of a novel biomimetic artificial photosynthesis membrane, aptly dubbed the “artificial leaf.” On October 21, they announced a significant advancement in the area of solar photocatalytic water splitting for green hydrogen production. Their innovative creation involves a patterned biomimetic semiconductor photocatalytic panel capable of spontaneously splitting water into stoichiometric hydrogen and oxygen gases under visible light irradiation.
The progress report came from the Shenyang National Laboratory for Materials Science at the Chinese Academy of Sciences, where the research team led by Dr. Liu Gang collaborated with both domestic and international partners. Their findings were recently published in the prestigious journal “Journal of the American Chemical Society.”
Dr. Liu noted that the team’s latest development offers a highly versatile and easily modularized solution. It integrates seamlessly with low-cost microelectronics fabrication processes, significantly lowering the barriers to large-scale application.
Delving into the inspiration for their work, Dr. Liu explained that plants efficiently utilize visible light for photosynthesis due to the orderly arrangement of two types of photosynthetic pigments, Photosystem I and II, within their thylakoid membranes. This arrangement facilitates charge transfer and enables energy to drive efficient photosynthetic reactions under visible light.
Inspired by this natural process, the researchers employed micro-nano integration techniques to create a patterned biomimetic photocatalytic panel on fluorine-doped tin oxide (FTO) transparent conductive glass. This innovative panel features alternating bands of hydrogen-producing and oxygen-producing semiconductor materials.
Through careful optimization of the work function between the semiconductors and the conductive substrate, the team achieved ohmic contact that promotes Z-type charge transfer. This effectively reduces the recombination of photogenerated electrons and holes, prolonging the average lifetime of these charges and allowing for their spatially ordered separation—resulting in their accumulation on the respective hydrogen and oxygen bands.
Building on these principles, Dr. Liu highlighted that the newly developed system can leverage the orderly accumulation of photogenerated electrons and holes under visible light to spontaneously split water, generating hydrogen and oxygen in a precise stoichiometric ratio.
He emphasized the potential of solar photocatalytic water splitting to produce green hydrogen, describing it as a cutting-edge, transformative low-carbon technology. This process utilizes both ultraviolet and visible light from the solar spectrum to drive the photocatalytic reaction necessary for water splitting, making efficient semiconductor photocatalysts essential for its practical application.
After nearly five decades of research, the efficiency of semiconductor photocatalysts in utilizing ultraviolet light—representing less than 5% of the solar spectrum—has approached 100%. In contrast, the efficiency of harvesting visible light, which constitutes around 45% of the spectrum, remains relatively low. This is largely due to the lower energy of visible light, which is insufficient to generate the required photogenerated electrons and holes needed to initiate water-splitting reactions. Thus, achieving efficient visible light photocatalytic water splitting represents the pinnacle of current research in the field of solar energy production.
