Metal-Organic Framework Templated Pd/CeO2@N-doped Carbon for Low-temperature CO Oxidation

A new Pd/Ce based metal-organic framework is designed and synthesized as self-sacrificial template for fabrication of efficient catalyst for CO oxidation. The catalyst obtained by thermal annealing at 700 oC (Pd/CeO2@NC-700) is composed of N-doped carbon with embedded Pd and CeO2 nanoparticles, which are highly dispersed and closely connected in N-doped carbon, jointing the high Pd loading (33.7 wt %) and the coupling between Pd and CeO2 phase to synergistically boost the CO oxidation performance. The Pd/CeO2@NC-700 catalyst exhibits a 100 % conversion temperature of 89 °C and excellent long-time stability. By combining structure characterizations with density functional theory calculations, two possible CO oxidation pathways of TPB and TOP are revealed, in which the adsorbed O2 directly dissociates to O* atom and activates CO* molecule. The transfer of O* between Pd and Ce (TPB) or Pd and Pd (TOP) facilitates the formation of CO2* intermediates and finally results in the production of CO2. This work would provide a new insight into the development of novel efficient catalysts for CO oxidation based on metal-organic frameworks.