Effect of support on the formation of CuPd alloy nanoparticles for the hydrogenation of succinic acid

Abstract

Three kinds of supported CuPd catalysts are studied for the hydrogenation of succinic acid (SA) to value-added chemicals including γ-butyrolactone (GBL), 1,4-butanediol (BDO), and tetrahydrofuran (THF). The strength of metal–support interaction played an essential role in the construction of CuPd nanoparticles (NPs), inducing different catalytic activity and selectivity. In-depth characterizations revealed that while homogeneous alloys were dominantly constructed on TiO2 and SiO2 supports, heterogeneous alloy with a great extent of Cu segregation was preferably formed on γ-Al2O3. Although a high GBL selectivity was achieved over CuPd/TiO2, large particles with the least Cu segregation caused a lower SA conversion while preventing it from further hydrogenation. In contrast, smaller CuPd NPs with a minority of Cu segregation on SiO2 made it a superior catalyst in the BDO production. Notably, strong Lewis acid sites on γ-Al2O3 occupied a major role in the formation of highly selective THF with a nearly quantitative yield.