Rational design of zeolite Y supported oxalate and borohydride ligands functionalized Cu catalysts for CO2 conversion to specialty chemicals

Abstract

This study investigates the effect of oxalate and borohydride ligands functionalization on the properties and activity of zeolite Y (ZY) supported copper nanoparticles in CO2 hydrogenation to specialty chemicals. The ZY-supported copper oxalate (CuX-ZY) and copper borohydride (CuB-ZY) catalysts exhibited a drastic difference in physicochemical properties compared to a benchmark copper supported on ZY (Cu-ZY) catalyst without any functionalization. The average Cu particle sizes are 7.74, 0.69, and 0.57 nm for Cu-ZY, CuX-ZY, and CuB-ZY, respectively. The smaller the copper oxide particle sizes, the higher the reduction temperatures to the metallic state due to strong-metal-support-interactions. The CO2 conversions (XCO2) at 270 °C are 28.3%, 26.4%, and 14.6%, for CuX-ZY, CuB-ZY, and Cu-ZY which aligns with the trend of basic site-strength, Cu particle sizes, and Cu dispersion of the catalysts. While methanol yield was maximum at 70.5 gproduct gcat−1 ∙ min−1 over CuX-ZY, the dimethyl ether was maximum at 48.9 gproduct gcat−1 ∙ min−1 over CuB-ZY. Furthermore, the oxalate and borohydride functionalization were effective in minimizing CO formation.