Electrochemical Oxidation of Methanol on Pt-SnO_x/C Catalysts Characterized by Electrochemistry Methods

Abstract

Pt-SnOx/C catalysts with Pt/Sn atomic ratio of 1:1, 2:1, 3:1, 4:1 and 5:1 were prepared by the impregnation method. The electrochemical process of methanol oxidation on these five catalysts was studied using cyclic voltammetry and electrochemical impedance spectroscopy two simple real-time methods. Impregnation is a stable way to prepare Pt-SnOx/C catalysts with accurate stoichiometry and uniform particle size, which increased from 3.8 nm to 5.4 nm as the Sn content decreased. The maximum current density of methanol electrochemical oxidation initially increased and then decreased with the Sn content, and Pt3-SnOx/C exhibited the highest value of about 16.6 mA·cm−2. Methanol electrochemical oxidation on the Pt-SnOx/C catalyst surface changed from adsorption to dehydrogenation, to hydrolysis and finally oxidation as the electrode potential increased from 0 V to 0.85 V. The main intermediate created during methanol electrochemical oxidation was COads. The existence of Sn atoms decreased the onset potential of the hydrolysis reaction, and consequently promoted methanol electrochemical oxidation. Interestingly enough, the highest reaction rate was obtained at about 0.65 V due to similar reaction rates of COads oxidation and methanol dehydrogenation.

High Electrocatalytic Activity of Pt/C Catalyst Promoted by TT‐Nb2O5 Nanoparticles under Acidic Conditions

“…The corresponding XRD patterns of Nb 2 O 5 promoted Pt/C and bare Pt/C samples are shown in Figure . As can be seen that the characteristic diffraction peak at about 24.8° corresponds to the (002) plane of graphitic Vulcan carbon . The representative diffraction peaks for the face centered cubic (fcc) Pt crystallites are observed at 39.7° (111), 46.2° (200), 67.7° (220) and 81.4° (311), respectively.…”

“…However, not all the peaks of Nb 2 O 5 could be identified in the composites, since some of the diffraction peaks are overlapped with Pt diffraction peaks. Besides, the diffraction peaks of Pt in the Pt/nano‐TT‐Nb 2 O 5 /C and Pt/bulk‐T‐Nb 2 O 5 /C composites are very broad and significantly lower in intensity compared to Pt/C, indicating very high dispersion of Nb 2 O 5 in the composites ,. According to Vegard's law and Scherrer formula, we have calculated lattice parameter and average crystallite sizes of the catalysts by using Pt (220) plane.…”

Pt and RhPt dendritic nanowires and their potential application as anodic catalysts for fuel cells

“…In addition the absence of a "pseudo-inductive" loop which is common for Pt based catalyst for this reaction implies that the binding of CO to the surface may be weak and this compliments the large poison resistance noted by this catalyst. [59][60][61] Regarding, formic acid oxidation, we assessed the electrocatalytic activities of our Pt and RhPt dendritic NWs by CV in a 1 M H 2 SO 4 solution containing 0.5 M formic acid (Fig. 8).…”

Noble Metal‐Based Multimetallic Nanoparticles for Electrocatalytic Applications

“…[ 346 ] Various multimetallic catalysts showed enhanced performance in combination with different oxide supports, which has been explained by two main reasons. [ 347 , 348 , 349 , 350 , 351 , 352 ] First, OH groups on the oxide surface facilitate the removal of CO ad on the metal sites via bifunctional mechanism and increase MOR activity, because CO ad (reaction intermediate of MOR) is strongly adsorbed and blocks (poison) the active surface of metal nanoparticles. Second, the electronic effect between metal nanoparticles and metal oxide supports improves charge transfer between them.…”