Hierarchical porous NiO as a noble-metal-free cocatalyst for enhanced photocatalytic H_(2) production of nitrogen-deficient g-C_(3)N_(4)

摘要

Graphitic carbon nitride with nitrogen vacancies(NV-g-C_(3)N_(4))as a photocatalyst has been studied in solardriven energy conversion.However,expensive and rare noble metal co-catalysts such as Pt or Pd are required in the photocatalytic H_(2)evolution.Consequently,the exploration of low-cost and high-performance co-catalysts to replace expensive and rare noble metals has received more and more attention.Herein,a novel hierarchical porous NiO anchored on NV-g-C_(3)N_(4)is successfully fabricated.The NV-g-C_(3)N_(4)/NiO photocatalysts exhibited outstanding H_(2)evolution rate under visible light irradiation in absence of noble metal cocatalysts.The optimized NV-g-C_(3)N_(4)/NiO(the mass ratio of NiO is*1.7%)achieved a maximum H2 evolution rate of 170.60 lmol·g^(-1)·h^(-1),exhibiting*8.3-fold enhancement as compared to that of NV-g-C3N4.NiO as co-catalyst provided more active sites for photocatalytic H2 evolution.Moreover,on the interface of NV-g-C_(3)N_(4)/NiO,an interface electric field is formed between NiO and host nitrogen-vacated g-C3N4,facilitating the transfer of the photogenerated electrons from NV-g-C_(3)N_(4)to NiO co-catalyst,resulting in significantly promoted migration and separation efficiency of the photogenerated charge carriers.