Pd nanoparticles supported on CeO2 nanospheres as efficient catalysts for dehydrogenation from additive-free formic acid at low temperature

Pd nanoparticles (NPs)-based catalysts were synthesized, characterized, and used to efficiently catalyze hydrogen generation from formic acid (FA). A facile deposition-precipitation (DP) method was employed to synthesized Pd*CeO2 catalysts with the assistance of polyvinylpyrrolidone (PVP) as a surfactant. The Pd NPs were uniformly dispersed on the surface of CeO2 nanospheres to form x wt% Pd*CeO2 catalysts with various Pd loading amount (x = 0.5, 1, 3, 5, 10). The structural, morphological, surface properties were comprehensively investigated by various techniques including XRD, N2 adsorption-desorption, FE-SEM, HRTEM, XPS, Raman, H2-TPR and ICPMS. In particular, the Strong Metal-Support Interactions (SMSI) located at the interface between the active Pd NPs and the CeO2 support has been demonstrated through direct observations of hydrogen spillover phenomena and several advanced characterizations. With the increase of Pd loading, the catalytic efficiency of Pd*CeO2 catalysts was also improved. The prepared 10 wt% Pd*CeO2 catalyst exhibited the highest activity towards dehydrogenation of additive-free formic acid at 313 K, corresponding to an initial turn over frequency as high as 807.7 h-1. The superior performance of 10 wt% Pd*CeO2 could be attributed to the high dispersion of Pd NPs, more electron-rich Pd active sites and of course the SMSI between Pd and CeO2.