Nickel-coated silicon photocathode for water splitting in alkaline electrolytes
photoelectrochemical water splitting, silicon photocathode, nickel
Photoelectrochemical (PEC) water splitting is a promising approach to harvest and store solar energy . Silicon has been widely investigated for PEC photoelectrodes due to its suitable band gap (1.12 eV) matching the solar spectrum . Here we investigate employing nickel both as a catalyst and protecting layer of a p-type silicon photocathode for photoelectrochemical hydrogen evolution in basic electrolytes for the first time. The silicon photocathode was made by depositing 15 nm Ti on a p-type silicon wafer followed by 5 nm Ni. The photocathode afforded an onset potential of ~0.3 V vs. the reversible hydrogen electrode (RHE) in alkaline solution (1 M KOH). The stability of the Ni/Ti/p-Si photocathode showed a 100 mV decay over 12 h in KOH, but the stability was significantly improved when the photocathode was operated in potassium borate buffer solution (pH ≈ 9.5). The electrode surface was found to remain intact after 12 h of continuous operation at a constant current density of 10 mA/cm2 in potassium borate buffer, suggesting that Ni affords good protection of Si based photocathodes in borate buffers.
Tsinghua University Press
Ju Feng,Ming Gong,Michael J. Kenney,Justin Z. Wu,Bo Zhang,Yanguang Li,Hongjie Dai, Nickel-coated silicon photocathode for water splitting in alkaline electrolytes. NanoRes.2015, 8(5): 1577–1583