Stable and high-performance N-micro/mesoporous carbon-supported Pt/Co nanoparticles-GDE for electrocatalytic oxygen reduction in PEMFC

Bimetallic ZIF-Based PtCuCo/NC Electrocatalyst Pt Supported with an N-Doped Porous Carbon for Oxygen Reduction Reaction in PEM Fuel Cells

“…Co-ZIF and CuCo-ZIF undergo high-temperature pyrolysis, evaporating numerous unstable organic groups and leaving mostly carbon structures . As shown in Figure c,d, the particle surface of the two ZIF structures loaded with Pt became rough after high-temperature calcination, which may be due to the generation of metal nanoparticles, in which the ZIF structure of PtCo/NC significantly collapsed after high-temperature calcination, and there is obvious agglomeration phenomenon, which is probably due to the contraction of the carbonization procession . In contrast, PtCuCo/NC formed a uniform nanoporous carbon structure with a relatively uniform pore distribution.…”

“…It also shows that the incorporation of Cu promotes the formation of disordered carbon and nongraphite carbon, showing more structural defects. Carbon defects are attributed to heteroatomic doping and can optimize the charge state of carbon materials, improve the surface adsorption/desorption behavior of intermediate products, and increase the active site density, thus improving the electrocatalytic performance. ,, …”

“…48 As shown in Figure 3c,d, the particle surface of the two ZIF structures loaded with Pt became rough after high-temperature calcination, which may be due to the generation of metal nanoparticles, in which the ZIF structure of PtCo/NC significantly collapsed after hightemperature calcination, and there is obvious agglomeration phenomenon, which is probably due to the contraction of the carbonization procession. 16 In contrast, PtCuCo/NC formed a uniform nanoporous carbon structure with a relatively uniform pore distribution. The morphology and structure of carbon The metal/metal alloy particle dispersion of PtCo/NC and PtCuCo/NC was observed using TEM, as shown in Figure 3e,f.…”

“…Carbon defects are attributed to heteroatomic doping and can optimize the charge state of carbon materials, improve the surface adsorption/desorption behavior of intermediate products, and increase the active site density, thus improving the electrocatalytic performance. 16,53,56 To understand the surface chemical state of the PtCuCo/ NC catalyst, XPS tests were conducted and the corresponding spectra are shown in Figure 5. Figure 5b 5c).…”

“…44,55 XPS results show that the total N content of CuCo/ NC is 4.29% and that of Co/NC is 1.17%; thus, it can be concluded that Cu facilitates the introduction of N into the carbon structure, improving the doping amount of N. In addition, Figure 5e shows that most of the N species comprise pyridine N and graphite N, which are considered active sites for ORR. 16,35 Therefore, after the incorporation of Cu, the N content is significantly increased, while pyridine N and graphite N, which can act as active sites, have excellent charge transferability and can reduce the energy barrier to promote oxygen adsorption, improving the electrocatalytic performance. 58 We performed the XPS analysis of Pt.…”