Direct Growth of Polymeric Carbon Nitride Nanosheet Photoanode for Greatly Efficient Photoelectrochemical Water-Splitting.

A general method for the direct synthesis of highly homogeneous and dense polymerized carbon nitride (PCN) nanosheet films on F: SnO 2 (FTO) is developed. Detailed photoelectrochemical (PEC) water-splitting studies reveal that the as-synthesized PCN films exhibit outstanding performance as photoanode for PEC water-splitting. The optimal PCN photoanode exhibits excellent photocurrent density of 650 µA cm -2 , and monochromatic incident photon-to-electron conversion efficiency (IPCE) value up to 30.55% (λ = 400 nm) and 25.97% (λ = 420 nm) at 1.23 V RHE in 0.1 m KOH electrolyte. More importantly, the PCN photoanode has an excellent hole extraction efficiency of up to 70 ± 3% due to the abundance of active sites provided by the PCN photoanode nanosheet, which promotes the transport rates of OER-relevant species. These PCN films provide a new benchmark for PCN photoanode materials.