Trimetallic MOF1@MOF2 heterostructure derived Co–NC@CuM–C for enhanced photothermal catalysis in styrene epoxidation

Abstract

Constructing hierarchical MOF1-on-MOF2 composites using different binary MOFs is a promising strategy to develop multifunctional MOF precursors and their derivatives. However, the orientated growth of the heteroid MOF shell requires overcoming the mismatched cell lattices. Therefore, the desired assembly of MOF1@MOF2 with regular morphologies and sizes remains a significant challenge. Herein, a novel tri-metallic BMZIF@HKUST-1 with good dodecahedral morphology was successfully fabricated and pyrolyzed to obtain porous Co–NC@Cu–C, in which Cu and Co species were highly dispersed in the carbon skeleton and no agminated metal particles were observed. Interestingly, the carbon materials exert a good photothermal effect and can raise the system temperature from 25 to ∼50 °C under visible light irradiation. In addition, a metal ion redox exchange strategy was adopted to avoid runoff of unstable Cu species in Co–NC@Cu–C during catalysis under harsh conditions. The optimal Co–NC@CuOPd–C achieved excellent activity (99%) and high selectivity (92.9%) in styrene epoxidation by photothermal catalysis benefitting from its multiple active sites and highest stability. The novel synthetic strategy can be further extended to more MOF types and provides plentiful metal sites for producing various fine chemicals.