Selective solar-driven CO2 reduction mediated by 2D/2D Bi2O2SiO3/MXene nanosheets heterojunction

• An ecofriendly 2D/2D heterojunction of Bi 2 O 2 SiO 3 /Ti 3 C 2 was synthesized by a simple wet chemical process. • 2D/2D Bi 2 O 2 SiO 3 /Ti 3 C 2 heterojunction boosts the photo-reactivity of Bi 2 O 2 SiO 3 for CO 2 reduction. • The 2D/2D heterojunction own a short charge transfer distance resulting in effective charge transfer. • The enhanced photocatalytic mechanism of the system was clarified by DFT study. Photocatalytic CO 2 reduction reaction (CO 2 RR) is an environment-friendly technique for clean fuel generation. Developing low-cost and efficient photocatalyst/cocatalyst systems for boosting CO 2 RR is still a challenge. Herein, a novel Bi 2 O 2 SiO 3 /Ti 3 C 2 2D/2D heterojunction photocatalysts are successfully prepared by in situ growth of Bi 2 O 2 SiO 3 on the surface of ultrathin Ti 3 C 2 nanosheets, a kind of MXenes. The observed Bi 2 O 2 SiO 3 /Ti 3 C 2 (BOSO/TC-2) hybrids exhibit a large interface contact area companied with enhanced CO 2 adsorption capability, illustrating excellent 2D/2D interfacial charge transfer behaviors. The total yield of products obtained on the optimized BOSO/TC-2 photocatalyst is 3.8 times that of pristine Bi 2 O 2 SiO 3 nanosheets and achieve near 90% selectivity for CO over CH 3 OH without sacrificial agents, which was higher than most all inorganic Bi-based photocatalysts. Moreover, the mechanism of enhanced photocatalytic activity and reaction pathway was proposed in terms of the DFT study and in situ FTIR analysis. This work might provide new semiconductor/cocatalyst systems for selective CO 2 photoreduction to solar fuels.