Sn and dual-oxygen-vacancy in the Z-scheme Bi2Sn2O7/Sn/NiAl-layered double hydroxide heterojunction synergistically enhanced photocatalytic activity toward carbon dioxide reduction

• Published in: Journal of colloid and interface science 2023-12, Vol.652, p.1126-1137
• Main Authors: Zhang, Shiming, Fan, Songyu, Liang, Ting, Wei, Jingwen, Zhu, Tingting, Shen, Yuxiang, Yu, Zebin, Zhu, Hongxiang, Wang, Shuangfei, Hou, Yanping
• Format: Article
• Language: English
• Subjects: CO2 photoreduction; CO2 reduction intermediates; Dual oxygen vacancies; Interfacial charge transfer; Z-scheme Bi2Sn2O7/Sn/NiAl-LDH heterojunction
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.08.145

[Display omitted] •Sn and dual-oxygen-vacancy mediated Z-scheme Bi2Sn2O7/Sn/NiAl-LDH was synthesized.•The VO,O-Bi2Sn2O7/Sn/NiAl-LDH showed desired photoelectrochemical properties.•The SPR effect of Sn and oxygen defects accelerated charges separation and transfer.•Superior CO2 photoreduction performance was achieved by VO,O-Bi2Sn2O7/Sn/NiAl-LDH.•The mechanism of CO2 photoreduction on the VO,O-Bi2Sn2O7/Sn/NiAl-LDH was proposed. Photocatalytic conversion of carbon dioxide (CO2) into high value-added chemicals is an attractive yet challenging process, primarily due to the readily recombination of hole-electron pairs in photocatalysts. Herein, dual-oxygen-vacancy mediated Z-scheme Bi2Sn2O7/Sn/NiAl-layered double hydroxide (VO,O-20BSL) heterojunctions were hydrothermally synthesized and subsequently modified with Sn monomers to enhance photocatalytic activity toward CO2 reduction. The abundance of oxygen vacancies endowed the VO,O-20BSL with extended optical adsorption, enhanced charges separation, and superior CO2 adsorption and activation. The interfacial charges transfer of the VO,O-20BSL was demonstrated to follow a Z-scheme mechanism via photochemical deposition of metal/metal oxide. Under visible light irradiation, the VO,O-20BSL exhibited the highest yields of carbon monoxide (CO) and methane (CH4), with values of 72.03 and 0.85 umol·g−1·h−1, respectively, which were 2.66 and 1.57 times higher than that of the VO-NiAl-layered double hydroxide (VO-1LDH). In situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) revealed that carboxylic acid groups (COOH*) and aldehyde groups (CHO*) were the predominant intermediates during CO2 reduction, and accordingly, possible CO2 reduction pathways and mechanism were proposed. This study presents a feasible approach to incorporate dual vacancies into Z-scheme heterojunctions for CO2 reduction.