Hollow core-shell 30Cu6Ce/0.6Si@Ti catalysts for 1,4-butynediol synthesis via ethynylation of formaldehyde: the formation path of polyacetylene

Abstract

1,4-Butynediol is mainly synthesized in ethynylation reaction of formaldehyde catalyzed by Cu-based catalysts. The stability of Cu2C2 in a reducing atmosphere remains a serious challenge. In this study, a 30Cu6Ce/0.6Si@Ti catalyst with hollow core-shell structure was successfully synthesized via a solvothermal-coprecipitation method. When applied in the ethynylation of formaldehyde, the catalyst demonstrated superior performance compared to commercial alternatives, achieving 79% yield and 96% selectivity for 1,4-butynediol while reducing the reaction activation energy from 27.80 kJ·mol-1 to 23.20 kJ·mol-1. Moreover, the catalyst exhibited excellent cycling stability over 100 h of continuous operation. The characterization results revealed that the 30Cu6Ce/0.6Si@Ti catalyst exhibited CuO nanoparticles highly dispersed in core-shell structure. Notably, the Cu-Ce electron interaction and the well-designed hollow Si@Ti core-shell structure effectively improved the stability of the active Cu2C2 leading to high ethynylation performance. The formation of the polyacetylene was further elucidated through comprehensive Raman spectroscopic characterization coupled with experimental validation. This work improves the stability of active Cu2C2 and paves the way for designing high-performance core-shell Cu-based catalysts for formaldehyde ethynylation, with both theoretical significance and practical implications.