Highly effective synthesis of dimethyl carbonate over CuNi alloy nanoparticles @Porous organic polymers composite

Greenhouse effect raised by the carbon dioxide emissions has become a pivotal resolved issue at present. The direct synthesis of dimethyl carbonate (DMC) from CO 2 and methanol is one of infusive green pathways. In this study, a novel CuNi alloy nanoparticles encapsulated in a thermal stable triphenylphosphine porous organic polymers (POP-PPh 3 ), Cu x Ni y @POP-PPh 3 catalysts, is synthesized and then explored in the direct DMC synthesis reactions. The Cu x Ni y @POP-PPh 3 catalysts are fully characterized by a series of techniques, such as transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), N 2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature programmed reduction (H 2 -TPR). TEM images show the CuNi particles are around 7 nm, and XPS analyses demonstrate the alloy particles comprise of a metallic (CuNi) 0 core and a thin Ni 2 O 3 surface. The Cu x Ni y @POP-PPh 3 catalysts, fixed into a honeycomb ceramic to give a monolithic catalyst, show an excellent catalytic performance (a 10.5% methanol conversion with an 80% DMC selectivity) during the direct DMC synthesis reactions in a fixed bed reactor. The high catalytic performance over Cu x Ni y @POP-PPh 3 catalysts is mainly attributed to the pore structure of POP-PPh 3 , uniform distribution of alloy nanoparticles, and the unique performance of the monolithic catalyst ( e.g ., removing by-product of water in time).