Vertically standing Cu2O nanosheets promoted flower-like PtPd nanostructures supported on reduced graphene oxide for methanol electro-oxidation

Nanohybrid layered double hydroxide materials as efficient catalysts for methanol electrooxidation

“…Therefore, EIS spectra can display a large variety of features, including inductive loops, negative resistance, and multiple time constants. 44,[49][50][51][52][53][54][55][56][57][58][59][60][61] In our case, the spectra presented broad semicircles that could not be t with a Randles circuit; instead, two relaxation constants could be identied, which has been observed before. 44 Likewise, the semicircles were depressed, thus constant phase elements (CPEs) were included in the t in order to account for surface heterogeneities detected with TEM microscopy.…”

“…It is used to characterize complex electrochemical reactions, along with faradaic and non-faradic processes. 48 In alkaline media, the mechanistic details of methanol oxidation may be summarized by the following general equations 49,50 M + OH À / M-(OH) ads + e À where M represents an active metallic site at the surface of the electrode. This mechanism consists in the oxidative adsorption of the hydroxyl ion (eqn (1)) followed by the oxidative adsorption and dehydrogenation of methanol to yield adsorbed carbon monoxide (eqn (2)).…”

“…Thus, our impedance data support the fact that the step represented by eqn (3) is not determining the overall electrocatalytic process, but it is the methanol dehydrogenation step (eqn (2)) the key kinetic reaction in the mechanism. 50 The catalytic activity of these catalysts is embodied in the R CT parameter, and shall be given special attention in this discussion. The evolution of R CT vs. methanol concentration is depicted in Fig.…”

Enhanced Electrocatalytic Oxidation of Methanol on Pt‐Decorated Bi2WO6/Graphene Nanosheets with Visible Light Assistance

“…To further reveal the electron transfer kinetics on the Pt-Bi 2 WO 6 /RGO electrode, the EIS spectra were studied at different potentials from -0.6 to 0 V. [40,41] As shown in Figure 9A,B, the DIAs gradually decrease from -0.6 to -0.3 V with the potentials increase under visible light, which is attributed to the removal of intermediate products and more active sites during the methanol oxidation process. Nevertheless, when the potential reaches -0.2 V, the DIA reverses from the first quadrant to the second quadrant and the impedance is negative, which means that the increase in the polarization potential leads to the decline of the current, revealing the relatively high potential gives rise to the poisoning of catalyst.…”

On the Origin of the Enhanced Performance of Pt/Dendrite‐like Mn3O4 for Methanol Electrooxidation

“…[6] Accordingly, fabricating low-cost electrocatalytic materials with high activity and improved tolerance to CO ads poisoning is quite urgent for DMFCs' commercialization. [13][14][15][16][17][18] One representative is Mn 3 O 4 , which has been used as support for catalysts towards oxygen reduction reaction, [19][20][21] alcohol or methanol oxidation reaction. Catalytic reaction is merely sensitive to surface atoms' composition, structure, defect and chemical state, so depositing nanosized catalyst on support or core can use as little amount of catalyst as possible to get as much active area and good catalytic effect as we can.…”