Methanol Oxidation Reaction Performance on Graphene‐Supported PtAg Alloy Nanocatalyst: Contrastive Study of Electronic and Geometric Effects Induced from Ag Doping

Abstract

In Pt‐based alloy catalyst, the electrocatalytic performance is highly related to the Pt d‐band center, whose position can be modulated by the synergetic interaction of electronic and geometric effects. In this study, graphene‐supported PtAg (PtAg/graphene) alloy nanocatalyst was prepared by a facile galvanic replacement reaction. Due to the introduction of Ag component, the PtAg/graphene exhibits a higher specific/mass activity (1.48 mA cm–2, 580 mA mgPt–1) and better CO tolerance (CO stripping potential: 0.45 V vs. Ag/AgCl) than those of commercial Pt/C catalyst (0.86 mA cm–2, 270 mA mgPt–1, 0.50 V vs. Ag/AgCl) when being applied for catalyzing methanol oxidation reaction (MOR). On the basis of component and structure characterization, the PtAg alloy catalyst model was constructed, and first‐principles density function theory calculation was applied to study the relative influence of electronic and geometric effects on the Pt d‐band center and CO binding energy, respectively. It is found that the electronic effect, i. e. the charge transfer from Ag to Pt, is the decisive factor to enhance the electrocatalytic performance of PtAg alloy towards MOR.

Synthesis and characterization of polydopamine‐derived carbon materials with enhanced thermoelectric performance

“…The diffraction peaks 2 θ were 23.57° ( d ≈ 0.32 nm), 21.74° ( d ≈ 0.35 nm), 22.47° ( d ≈ 0.34 nm), 22.35° ( d ≈ 0.34 nm), and 22.87( d ≈ 0.33 nm) from 2.64 to 13.12 mM, respectively. The peaks are weak and wide for all the samples, which is mainly caused by the generation of PDA amorphous morphology 29,30 . The peak shape becomes narrower and the diffraction angle is increased after PDA carbonization.…”

“…The peaks are weak and wide for all the samples, which is mainly caused by the generation of PDA amorphous morphology. 29,30 The peak shape becomes narrower and the diffraction angle is increased after PDA carbonization. According to the Bragg equation 2d sin θ = nλ (d represents the crystal plane spacing, θ the diffraction half angle, n the diffraction order, and λ the X-ray wavelength), the crystal plane spacing decreases, the grain size decreases, the crystallinity becomes larger, the molecular chain structure arrangement is more regular and compact, which promotes the carrier transmission and improves the conductivity.…”

Carbon‐Free Nanocoral‐Structured Platinum Electrocatalyst for Enhanced Methanol Oxidation Reaction Activity with Superior Poison Tolerance

“…During forward scan, MOR occurred according to the following reactions [Eqs. (2) and (3)]: …”

Glycine-Assisted Fabrication of N-Doped Graphene-Supported Uniform Multipetal PtAg Nanoflowers for Enhanced Ethanol and Ethylene Glycol Oxidation

“…The catalytic activity of these four electrocatalysts was measured by CV and CA tests carried out at a scanning rate of 50 mV/s in the corresponding solution. Among these catalysts, the G-A PtAg/NG catalysts are expected to exhibit the best EOR and EGOR activity together with durability owing to the increase of active areas, the synergistic effect in PtAg NFs, the addition of NG, and the uniform multipetal structure which endows them with more exposed surface area, improved durability, and high-efficiency electron transfer. , Herein, we selected EOR and EGOR as model systems for evaluating the electrochemical performance of G-A PtAg/NG, G-A PtAg, PtAg NFs, and Pt/C nanocatalysts. CO-stripping experiments of different catalysts were conducted to evaluate the CO antipoisoning degree of the catalysts (Figure S11); the onset potential of CO oxidation on the G-A PtAg/NG catalysts is apparently more negative than that on the G-A PtAg, PtAg, and Pt/C catalysts, indicating that the G-A PtAg/NG catalysts facilitate the removal of CO from the surface of PtAg NFs and the strong capability of antipoisoning of CO. , NG, as a catalytic support, helps to strengthen the electronic effects.…”