Review on g-C_(3)N_(4)-based S-scheme heterojunction photocatalysts

With the rapid development of economy and modern industry,serious environmental pollution and energy shortage have become major urgent challenges to the human society.Photocatalysis is a promising technology to provide green energy.As a typical metal-free polymer photocatalyst,g-C_(3)N_(4) has attracted more and more attention due to its excellent performance.Unfortunately,the fast recombination of photo-induced charges,limited light response range as well as weak oxidation ability are still the key drawback that restrict the photocatalytic performance of g-C_(3)N_(4).These problems can be effectively addressed by constructing g-C_(3)N_(4)-based heterojunctions with two or more semiconductor materials,during which the respective advantages can be integrated.Up to now,the various oxidation semiconductor photocatalysts have been tried to construct the novel S-scheme heterojunction photocatalysts with g-C_(3)N_(4).Thus,this review provides a comprehensive introduction of g-C_(3)N_(4)-based S-scheme heterojunctions,including the main characteristics of the S-scheme heterojunction,photocatalytic mechanisms,design rules and preparation methods of g-C_(3)N_(4)-based S-scheme heterojunction photocatalysts.Moreover,this review summarizes recently reported works on the potential applications of g-C_(3)N_(4)-based S-scheme photocatalysts in various important photocatalytic reactions,including photocatalytic hydrogen production,photocatalytic degradation of contaminants,photo-reduction of CO_(2) into fuels,and photocatalytic sterilization.Finally,based on the current research progress,we propose some shortages in the preparation methods and applications of g-C_(3)N_(4)-based S-scheme heterojunctions,which are to be further investigated and resolved in this promising and creative research field.