Zinc-Coordination Polymer-Derived Porous Carbon-Supported Stable PtM Electrocatalysts for Methanol Oxidation Reaction

Porous carbon (PC) is obtained by carbonizing a zinc-coordination polymer (MOF-5) at 950 °C and PtM (M = Fe, Co, Ni, Cu, Zn) nanoparticles (NPs), which are deposited on PC using the polyol method. Structural and morphological characterizations of the synthesized materials are carried out by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), and the porosity was determined using a N₂ adsorption/desorption technique. The results revealed that PtM NPs are alloyed in the fcc phase and are well dispersed on the surface of PC. The electrochemical results show that PtM/PC 950 catalysts have higher methanol oxidation reaction (MOR) performances than commercial Pt/C (20%) catalysts. After 3000 s of chronoamperometry (CA) test, the MOR performances decreased in the order of Pt₁Cu₁/PC 950 > Pt₁Ni₁/PC 950 > Pt₁Fe₁/PC 950 > Pt₁Zn₁/PC 950 > Pt₁Co₁/PC 950. The high MOR activities of the synthesized catalysts are attributed to the effect of M on methanol dissociative chemisorption and improved tolerance of Pt against CO poisoning. The high specific surface area and porosity of the carbon support have an additional effect in boosting the MOR activities. Screening of the first row transition metals (d ⁵⁺ , n = 1, 2, 3, 4, 5) alloyed with Pt binary catalysts for MOR shows that Pt with d ⁸ (Ni) and d ⁹ (Cu) transition metals, in equivalent atomic ratios, are good anode catalysts for alcohol fuel cells.