Energy Band Engineering of Polymeric Carbon Nitride with Indium Doping for High Enhancement in Charge Separation and Photocatalytic Performance

Metal doping is a valid strategy to increase simultaneously photoabsorption, the charge separation efficiency, and thus photocatalytic activity of polymeric carbon nitride (CN), however metal elements in IIIA–VA groups in the periodic table were rarely researched in doping CN. Herein, indium (In)-doped CN (In:CN) was firstly synthesized with In3+ ions inserted in the interlayer, approaching to the cavities in the monolayer sheets, and fixed through coordination with nitrogen atoms around. In:CN exhibits higher photoabsorption, specific surface area, charge separation and transfer efficiencies, and photocatalytic performance in H2 generation and environmental remediation than bulky CN. The H2 generation and rhodamine B decomposition rates for In:CN are ~2.9 and 4.6 times those for CN, respectively. The apparent quantum yield (420 nm) of In:CN for H2 production can reach 6.8%. The enhancement in charge separation plays an indispensable role for the photoactivity increase of In:CN, which originates from gene...