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 × 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 ICP-MS. 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.