Niobium Dioxide Facilitating Methanol Electrooxidation on Pt/C Catalyst by Synergistic Effect

Abstract

In this work, Pt nanoparticles are deposited on NbO2‐modified carbon composites and evaluated as promising direct methanol fuel cell (DMFC) electrocatalysts. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) indicate that Pt nanoparticles (about 2.5 nm) are uniformly dispersed on NbO2‐modified carbon composites. Electrochemical measurements show that the mass activity toward methanol electrooxidation on Pt/NbO2‐C is as high as 3.0 times that of conventional Pt/C. Meanwhile, the onset potential of CO oxidation is negatively shifted by about 46 mV as compared with that of Pt/C, which means that the synergistic effect between NbO2 and Pt facilitates the feasible removal of poisoning intermediate CO during methanol electrooxidation. X‐ray photoelectron spectroscopy (XPS) characterizations reveal the electron transfer from Nb to Pt, which suppress the poisoning CO adsorption on Pt nanoparticles and facilitate methanol electrooxidation. NbO2 nanoparticles facilitate methanol electrooxidation on Pt/C catalyst by synergistic effect and electronic effect, which represents a step in the right direction for the development of excellent fuel cell anode electrocatalysts.

Metal–Support Interactions in a Molybdenum Oxide Anchored PtNi Alloy for Improving Oxygen Reduction Activity

“… Carbon-supported metal oxide structure can effectively improve the defect of poor conductivity of MoO x and enhance the electron transmission efficiency during the reaction The anchoring effect of MoO x prevents the aggregation of PtNi nanoparticles and shedding of catalyst particles due to the corrosion of the carbon support, improving the durability. , Nitrogen doping can change the surface electronic properties of the carbon support and increase the defect sites (i.e., catalytically active sites), thereby improving the catalytic activity. − Besides, the Ni–N bond and nitrogen doping effect can also stabilize Ni in the alloy and the interaction between nanoparticles and supports and thus improve the durability. …”

“…The anchoring effect of MoO x prevents the aggregation of PtNi nanoparticles and shedding of catalyst particles due to the corrosion of the carbon support, improving the durability. , …”

Tailored NbO2 Modified Pt/Graphene as Highly Stable Electrocatalyst Towards Oxygen Reduction Reaction

“…It can be concluded that there is an interaction between Pt and NbO 2 , and the strong metal‐support interaction weakens the chemisorption of OH groups on the surface of the Pt active sites, thereby inhibiting the formation of Pt‐O bands and thus improving the ORR performance. The lateral repulsion between OH ads or O 2ads of Pt active sites and OH ads species on NbO 2 surface can weaken Pt‐O bond and release Pt active sites, which is particularly critical for an excellent ORR electrocatalyst , . All these strong interactions can form the unique TPB structure to produce some possible synergetic effect between Pt, graphene and NbO 2 , which is beneficial to provide the path of electron transfer among Pt, NbO 2 and graphene, thus effectively enhance the electrochemical activity and stability.…”

“…Figure 12 shows the schematic illustrations of the special TPB structure in Pt-NbO 2 -graphene electrocatalyst, and the pro-posed ORR mechanism. It can be concluded that there is an interaction between Pt and NbO 2 , and the strong metal-support interaction weakens the chemisorption of OH groups on the surface of the 27]. All these strong interactions can form the unique TPB structure to produce some possible synergetic effect between Pt, graphene and NbO 2 , which is beneficial to provide the path of electron transfer among Pt, NbO 2 and graphene, thus effectively enhance the electrochemical activity and stability.…”

“…According to the description in literature , NbO 2 is helpful to enhance both catalytic activity and stability in electrochemical field. This conclusion is consistent with our previous works . However, the metal oxides themselves have relatively low electronic conductivity and/or specific surface area.…”