Applied Catalysis A: General, Vol.561, 127-136, 2018
One-pot synthesized CePO4/Ni2P nanocomposites as general hydrogenation catalysts: The attractive contribution of CePO4
Cheap and robust compounds that can replace precious metal (PM) catalysts are eagerly anticipated for hydrogen-involved chemical transformations. Herein, Ce3+ and Ni2+ were co-bonded by HPO42- in a one-pot solvothermal synthesis system; then, the obtained precipitates were thermal-treated to obtain a series of Ce-Ni-P samples. With characterizations of XRD, XPS, SEM and HRTEM, the samples were featured as nanocomposites and as closely contacted CePO4 and Ni2P particles in both ca. 10.0-40.0 nm. Hydrogen adsorption-activation properties comparable to those of precious metals were discovered on the CePO4 component (H-2-TPD), making a main contribution in achieving the superior TOF of 0.06-0.51 s(-1) for hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL), with 92-99% selectivity on (CePO4)(m)/Ni2P nanocomposites (with molar ratio m of 0.12-4.6). The function of Ni2P was shown to activate CAL (CAL-TPD); then, a Langmuir-Hinshelwood mechanism was proposed and uncovered from the kinetic measurements. Superior catalytic hydrogenation performances were represented for two phenyl-alkynes and ten other alpha, beta-unsaturated carbonyl compounds, further indicating that CePO4/Ni2P nanocomposites serve as general hydrogenation catalysts; the features of low cost, robust structure and comparable properties to PM in both hydrogen activation and hydrogenation activity provide these nanocomposites with the potential to be PM substitutes for boosting correlating hydrogen-involved applications.
Keywords:CePO4/Ni2P nanocomposites;Hydrogen adsorption-activation;Precious metal substitute;Catalytic hydrogenation