Solution plasma method assisted with MOF for the synthesis of Pt@CoOx@N-C composite catalysts with enhanced methanol oxidation performance

Abstract

The key to direct methanol fuel cells (DMFCs) is the anode catalyst for methanol oxidation reaction (MOR) which has good catalytic activity and stability. Pt@CoOx@N-C catalysts were synthesized by compounding Pt nanoparticles and CoOx with nitrogen-doped porous carbon (N-C). Pt nanoparticles were prepared by solution plasma technique. CoOx@N-C are derived from zeolitic-imidazolate-framework-67 (ZIF-67) by heat treatment at 700 °C. For MOR, Pt@CoOx@N-C exhibits an outstanding electrocatalytic performance (mass activity of 2400 mA mgPt−1) and stability (70% remained after 300 cycles) under acidic condition, which owing to the synergistic effects among the Pt nanoparticles, CoOx and nitrogen-doped porous carbon. Pt@CoOx@N-C shows such mass activity superior to that of Pt/C (460 mA mgPt−1) due to the fact that CoO can adsorb –OH in the solution and then assist Pt to oxidize the CO-like intermediates to CO2 which improves the resistance to CO poisoning of Pt nanoparticles. Therefore, solution plasma method assisted with metal-organic frameworks have good development prospects on synthesis of highly efficient electrocatalysts.