Integrating CuInSe2 nanocrystals with polymeric carbon nitride nanorods for photocatalytic water splitting

Abstract

Developing photocatalysts with improved photoactivity and efficiency has remained an enduring theme both fundamentally and technologically in the field of photocatalysis. Polymeric carbon nitride (CN) has been widely exploited as an earth-abundant photocatalyst for water redox reactions. Nevertheless, the limited visible-light utilization rate and the high recombination rate of photoinduced charge carriers give rise to the moderate photocatalytic reactivity of CN in water splitting. Herein, p-type CuInSe₂ nanocrystals are prepared by a solvothermal approach and then immobilized with n-type CN nanorods through self-assembly and thermal treatment process, forming a CuInSe₂/CN hybrid photocatalyst. Benefiting from the p–n heterojunction, a 3% CuInSe₂/CN nanocomposite photocatalyst exhibits a three-fold increase in the hydrogen evolution rate (HER) compared to that of bare CN nanorods owing to the strengthened visible-light capturing capability and improved separation rate of photoexcited charge carriers. This work paves new avenues for the construction of p–n heterojunction photocatalysts for solar fuel production.