Fabrication of S-scheme CdS-g-CN-graphene aerogel heterojunction for enhanced visible light driven photocatalysis.

Constructing S-scheme heterojunction photocatalysts reveals a greatly improved separation efficiency of photogenerated carriers and enhanced harvesting ability of solar energy in photocatalytic field. Herein, a ternary CdS-g-CN-GA heterojunction has been fabricated by a facile ultrasound strategy, which behaved as a S-scheme heterojunction with an intimate interface formed, and GA played as an electronic transportation platform to promote the separation of photo-induced charge carriers, which was certified through photoelectrochemical techniques. Density functional theory calculations revealed that the different component in ternary CdS-g-CN-GA heterojunction demonstrated an obvious difference of work function, resulting in the charge transfer from CdS to g-CN through GA with S-scheme principle. In the optimized conditions, the S-scheme CdS-g-CN-GA heterojunction not only displayed greatly enhanced photocatalytic performances for degradation of dye and antibiotic wastewater, but also improved photocatalytic H production activity. In addition, the photocatalytic mechanism and driving force of charge transfer and separation in S-scheme CdS-g-CN-GA heterojunction were studied. This study offers a feasible strategy to construct a ternary S-scheme heterojunction for environmental and energy photocatalysis.