Facile synthesis of silicon-doped polymeric carbon nitride with enhanced photocatalytic performance

Abstract

Non-metal doping is an effective strategy to enhance the photocatalytic performance of polymeric carbon nitride (CN), but silicon (Si) doping in CN has never been realized yet. Herein, Si-doped CN (CNSi) was firstly prepared via a simple calcination process, by using (NH4)2SiF6 as the Si source, and exhibits prominently enhanced photocatalytic activity in H2 evolution from water splitting and for environmental purification. Its photocatalytic H2 production rate under visible light irradiation is 2.24 mmol g−1 h−1 which is ∼3 times that of CN, with an apparent quantum yield reaching ∼7% at 420 nm. The photoactivity improvement of CNSi arises from its prominent increase in photoinduced charge separation and transfer efficiencies. The doping mechanism of Si in CN is well illustrated. CNSi exhibits a high chemical stability and also great potential for application in solar energy conversion and environmental remediation. This work provides a novel way to modify CN and paves an avenue for synthesizing other Si-containing CN photocatalysts.