Microwave assisted construction of a SnOx/ZnSn(OH)6 heterojunction for photocatalytic CO2 cycloaddition

Abstract

The utilization of photochemical reactions to convert CO₂ and epoxides into valuable cyclic organic carbonates is a highly sought-after process in various industries. The development of a high-performance photocatalyst for this cycloaddition of CO₂ presents a significant challenge, particularly in the context of sustainability initiatives. To effectively harness light energy for CO₂ value-added processes, we have engineered a SnO_x-decorated perovskite-type ZnSn(OH)₆ photocatalyst. Through analysis using UV-Vis and Mott–Schottky plots, we have gained insights into the electronic structure of the materials, including adsorption, band gap, and band position. The incorporation of SnO_x into the ZnSn(OH)₆ cube has significantly improved charge transfer, as demonstrated by photocurrent and Nyquist measurement. This molecular framework lays the foundation for the high photocatalytic performance and stability exhibited by SnO_x/ZnSn(OH)₆ in facilitating the cycloaddition of CO₂ and various epoxides to produce cyclic carbonates. The SnO_x/ZnSn(OH)₆ catalyst demonstrates high performance, achieving an impressive yield of ≈95% and reaction activity of 4750.0 µmol g⁻¹ h⁻¹ with high values of green chemistry metrics (AE = 100%, RME = 92.98%, PMI = 5.99 and E factor = 4.99). This performance surpasses that of several other catalysts. Further examination through LSV, EPR and electron–hole scavenger tests has provided a deeper understanding of the reaction mechanism under light irradiation. Additionally, the materials have demonstrated good stability, highlighting their potential in sustainable processes.