Jiaojiao Jiao,Zexiang Wang,Jing Wang,Tiantian Yao,Zongliang Chen,Chen Chen,Li Sun,Xian Zhao,Weiliu Fan
The reasonable design of g-C 3 N 4 (CN)-based homojunctions is a promising method to improve the photocatalytic performance. Controlling the interfacial charge-transport process is challenging. Herein, Ag and P-doped CN (ACN and PCN) were selectively synthesized. The band edges of CN move downward continuously with increasing Ag or P doping concentration. CN/4ACN (type-II), CN/8PCN (S-scheme) and 4ACN/8PCN (S-scheme) were formed by suitable energy level matching, and their charge transfer mechanisms were confirmed via VB-XPS, UPS and ESR analysis. In the presence of the hole sacrificant triethanolamine (TEOA), both CN/4ACN and 4ACN/8PCN exhibited better H 2 evolution reaction (HER) rate than CN/8PCN due to the improvement in conductivity caused by Ag doping. However, only CN/8PCN and 4ACN/8PCN exhibited HER coupled with tetracycline (TC) degradation performance owing to the high redox potential of the S-scheme. Benefiting from a good carrier transport property and high redox potential, 4ACN/8PCN exhibited the best HER rate (2305.6 μmol·g −1 ·h −1 ) with TEOA as the hole sacrificant, which was 11.7 times than that of pure CN, respectively, and achieved a high HER rate (117.8 μmol·g −1 ·h −1 ) coupled with simultaneous TC degradation. This study provides a basic understanding of CN homojunctions, which shows potential for expanded applications in photocatalytic H 2 evolution and pollutant degradation.
Yixuan Lv,Dandan Ma,Chao Yang,Kunli Song,Le Shi,Yonghong Cheng,Chunming Niu,Jian-Wen Shi
Lead-free halide perovskites have enormous superiority in photoelectric devices, but low photocatalytic hydrogen evolution (PHE) hinders their application in photocatalysis. Here, a heterojunction composed of CsCu 2 I 3 (CCI) perovskite and graphite carbon nitride (CN) is constructed by in-situ hot-injection method for the first time. The resultant CCI/CN presents a significantly enhanced PHE performance from hydroiodic acid (HI) splitting with a PHE rate of 2212 umol/g/h, which is four times higher than CCI and nearly ten times higher than CN. It is revealed that a unique N-I bond is formed by the connection of N in CN and I in CCI at the interface between CN and CCI, which serves as a fast channel for the transfer of photogenerated electrons to establish a type II mechanism, effectively promoting the PHE performance. This study provides ideas and methods for the construction of type II photocatalyst for hydrogen production using lead-free halide perovskite.
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