Enhancing Photocatalytic CO <sub>2</sub> Reduction and Photo-oxidative Coupling over CdS/S- <i>g</i> -C <sub>3</sub> N <sub>4</sub> Heterojunction Interface into Solar Chemicals
Satyam Singh, Seung Yeon Choi, Rajesh K. Yadav, Chae Yeong Na, Jeongjin Kim, Myong Yong Choi, Tae Wu Kim
Abstract
High Resolution Image Download MS PowerPoint Slide Graphitic carbon nitride (g-C 3 N 4 ) has gained attention as a metal-free photocatalyst to generate solar chemicals via efficient solar-driven CO 2 reduction reactions. Even though the pristine g-C 3 N 4 and its analogous ones have excellent chemical properties, a disordered structure observed in various types of g-C 3 N 4 hinders the efficient charge separation process as well as the transport of photoexcited charge carriers linked to the photocatalytic performance. To overcome this limitation, we employed the introduction of a heterojunction architecture into sulfur-doped g-C 3 N 4 with CdS. By using the self-assembled method, we fabricated the CdS/S- g -C 3 N 4 heterojunction photocatalyst and designed a hybrid artificial photosynthetic module including a CdS/S- g -C 3 N 4 photocatalyst and biological enzyme for the generation of HCOOH from CO 2 . From the photocatalytic test, it was confirmed that the presence of the interfacial heterojunction in CdS/S- g -C 3 N 4 showed the enhanced production of formic acid that is much higher than that in the pristine S- g -C 3 N 4 . The systematic spectroscopic measurements provide mechanistic insights for the photoinduced electronic dynamics linked to the macroscopic photocatalytic performance in the CdS/S- g -C 3 N 4 heterojunction photocatalyst. Our study suggests that the artificial photosynthesis based on the heterojunction architecture-embedded photocatalyst will offer a promising and sustainable strategy for fixing CO 2 and generating solar chemicals.