Negative inductive effect enhances charge transfer driving in sulfonic acid functionalized graphitic carbon nitride with efficient visible-light photocatalytic performance

Abstract

Efficient photogenerated carrier migration/separation plays a critical role in increasing the photocatalytic performance of g-C3N4. Herein, sulfonic acid group-functionalized g-C3N4 (SACN) was synthesized and then synchronously strengthened by a facile-solid-state thermal reaction of g-C3N4 and sulfamic acid. As a solid strong acid, sulfamic acid can be used to achieve acid etching on the surface of g-C3N4 with the assistance of thermal treatment, leading to an enlarged specific surface area and increased surface catalytic reaction sites. More importantly, our experiments and density functional theory calculations indicate that the driving force generated by the negative inductive effect of sulfonic acid groups significantly improves the charge transfer dynamics and effectively inhibits their recombination. Moreover, the negative inductive effect can induce charge redistribution, which reduces the conduction band potential of g-C3N4 to enhance the reduction ability of photo-induced electrons. As a result, the SACN-400 sample showed excellent photocatalytic performance in H2 generation with an apparent quantum efficiency of 11.03% at 420 ± 15 nm, as well as an efficient photodegradation rate for organic pollutants.