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

Abstract

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 N 2 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 Pt 1 Cu 1 /PC 950 > Pt 1 Ni 1 /PC 950 > Pt 1 Fe 1 /PC 950 > Pt 1 Zn 1 /PC 950 > Pt 1 Co 1 /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 , 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.

A high-performance Pt-based catalyst for the methanol oxidation reaction: effect of electrodeposition mode and cocatalyst on electrocatalytic activity

“…The anodic peak current density ( J f ) and the onset potential ( E onset ) are important parameters that can judge the efficiency of a catalyst for MOR. 28,56 Fig. 3(B) demonstrates that the mass activities increase in the order of Pt/C (301.3 mA mg −1 Pt ) < p-Pt/MWCNT (847.8 mA mg −1 Pt ) < p-Pt/p-MDAB/MWCNT (1572.6 mA mg −1 Pt ) < p-Pt/NiCu/p-MDAB/MWCNT (2108.5 mA mg −1 Pt ).…”

“…Moreover, the more negative onset potentials of the synthesized catalysts compared to commercial Pt/C means that the synthesized catalysts have a higher MOR activity than state-of-the-art Pt/C. 56 The preference of p-Pt/p-MDAB/ MWCNT over c-Pt/p-MDAB/MWCNT for the MOR (Fig. S4B, ESI †) can be described by the smaller size and more widespread dispersion of Pt nanoparticles synthesized by the pulse mode in accordance with previous studies.…”

“…The constant value of 210 (mC cm À2 Pt ) is the charge required for adsorption of monolayer hydrogen on a shiny Pt surface. 56 By using eqn (3) and the value of loaded Pt (0.32 g m À2 ), the ECSA of p-Pt/NiCu/p-MDAB/MWCNT is calculated to be 64.8 m 2 g À1…”

“…The anodic peak current density ( J f ) and the onset potential (E onset ) are important parameters that can judge the efficiency of a catalyst for MOR. 28,56 Fig. 3(B Several factors may be considered to explain the enhanced MOR on the surface of p-Pt/CuNi/p-MDAB/MWCNT.…”

Synthesis of Doped/Hybrid Carbon Dots and Their Biomedical Application

“…The silver-doped CD (Ag-CD) nanoparticles on silica were engineered ( Figure 3 a) to form highly active surfaces enhanced by Raman scattering [ 64 ]. A number of researchers have also synthesized Zn-doped CDs for biomedical applications [ 69 , 72 , 73 , 74 , 75 , 76 ]. Dehydration, coordination, and carbonization are the steps required to synthesize Zn 2+ doped CDs ( Figure 3 b) according to Cheng et al [ 69 ].…”