Cu–Ce bimetallic metal–organic framework-derived, oxygen vacancy-boosted visible light-active Cu2O–CeO2/C heterojunction: An efficient photocatalyst for the sonogashira coupling reaction

Abstract

The development of an economical transition metal-based catalyst for photocatalytic carbon–carbon coupling reactions is aspiring. Herein, a Cu–Ce metal–organic framework (MOF) was synthesized and carbonized to produce bimetallic Cu2O–CeO2/C, which was utilized in the Sonogashira cross-coupling reaction. The defects and oxygen vacancies in the catalyst were characterized by X-ray photoelectron spectroscopy and Raman spectroscopy, while the nature of Cu was characterized by H2-TPR analysis. The defect-induced MOF-derived Cu–Ce heterojunction created more oxygen vacancies (OV) in CeO2, revealing the high photocatalytic activity. The Cu–Ce heterojunction (Cu2O–CeO2/C) formed a Cu(I)–phenylacetylide active complex and exhibited higher catalytic activity for the visible light-induced Sonogashira cross-coupling reaction. 25%Cu2O–CeO2/C offered 93.8% phenylacetylene conversion with a 94.2% Sonogashira product selectivity by using household light-emitting diodes. No discernible activity loss was observed from the recycling of the catalyst. Based on catalytic activity, control reactions, and physicochemical and optoelectronic characterization, the structure–activity relationship was established and a reaction mechanism was proposed. Replacement of the costly Pd metal-based catalyst with a cheap Cu2O–CeO2-based catalyst for the synthesis of commercially important compounds with a sustainable visible light-induced catalytic process will be highly attractive to chemists and industrialists.