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By smoothing the surface of the mineral hematite, a team of researchers led by Associate Professor of Chemistry Dunwei Wang achieved “unassisted” water-splitting, using the abundant rust-like mineral and silicon to capture and store solar hydrogen, the team reported last month in the journal Nature Communications.
Efforts to find an efficient solar water splitting method to mine electron-rich hydrogen for clean power have been hampered by hematite’s poor performance in the chemical reaction that separates hydrogen from oxygen in water.
By “re-growing” the mineral’s surface, the team produced a smoother version of hematite that doubled electrical yield, opening a new door to energy-harvesting artificial photosynthesis, according to Wang.
The project, which included colleagues from the University of California-Berkeley and China’s University of Science and Technology, marked the first use of earth-abundant hematite and silicon as the sole light absorbers in artificial photosynthesis.
“By simply smoothing the surface characteristics of hematite, this close cousin of rust can be improved to couple with silicon, which is derived from sand, to achieve complete water splitting for solar hydrogen generation,” said Wang. “This unassisted water splitting, which is very rare, does not require expensive or rare resources.”