Eco-Friendly Hydrogen: OHP Photoanode Boosts Water Splitting

• A research team has developed a highly efficient OHP-based photoanode for the production of hydrogen through photoelectrochemical water splitting. The team found that the addition of GTMACl to the OHP photoanode suppresses internal and external losses for an unprecedented efficiency.

Researchers from Gwangju Institute of Science and Technology (GIST), Korea Research Institute of Chemical Technology (KRICT) and Lawrence Berkeley National Laboratory have developed a highly efficient organometal halide perovskites (OHP)-based photoanode for the production of hydrogen through photoelectrochemical water splitting (PEC). This addresses limitations of current methods which use natural gas and produce greenhouse gases as by-products. Two limitations of OHP-based photoanodes, internal loss resulting from a recombination of photogenerated charge carriers, and external loss due to the slow reaction kinetics of water splitting, were simultaneously suppressed through the addition of glycidyltrimethylammonium chloride (GTMACl). The resulting Fe-doped Ni3S2/Ni foil/OHP photoanode achieved an unprecedented applied bias photon-to-current conversion efficiency of 12.79%, higher than that reported for OHP-based photoanodes in existing studies. The team also found that the GTMACl passivated the defects at the OHP/ETL interface, effectively suppressing undesired charge carrier recombination and improved light-soaking stability of the OHP cell, important for real-world PEC water splitting.

What Improves OHP-Based PEC Water Splitting?

• The addition of glycidyltrimethylammonium chloride (GTMACl) to the Fe-doped Ni3S2/Ni foil/OHP photoanode significantly improved the applied bias photon-to-current conversion efficiency of the photoanode to 12.79%.
• The GTMACl passivated the defects at the OHP/ETL interface, effectively suppressing undesired charge carrier recombination and improving light-soaking stability.
• A better understanding of the effects of GTMACl on the OHP-based photoanode could provide guidance for further improvement of PEC water splitting.
• Further study could include investigating different interfaces, such as OHP/metal and OHP/metal oxide.
• Exploring different dopants, such as Li, Pb, Bi, C and S, could also help to improve the efficiency of OHP-based PEC water splitting.
• The team could also investigate the effect of different buffer materials such as TiO2, WO3, ZnFe2O4, polymers and carbon nanotubes.