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

Abstract 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.