Deposition of PdPtAu Nanoparticles on Hollow Nanospheres of Fe₃O₄ as a New Catalyst for Methanol Electrooxidation: Application in Direct Methanol Fuel Cell

Modelling Reversible Inhibition of Irreversible Electro-Oxidation

“…Similar anomalous cyclic voltammograms that consist of anodic peaks in both anodic and cathodic branches were observed in electro-oxidations of ethanol [12 -16], glycerol [16,17] and formic acid [18]. Apart from pure platinum [1, 6 -8, 11, 14, 16, 18] and its alloys with ruthenium [2,3] and rhodium [13], various catalysts were used, such as palladium [5,10,12], gold [17], Fe2(MoO4)3 [4] and nickel [15]. On majority of electrodes the oxidation of methanol is faster after the reactivation than before the deactivation of catalyst.…”

The Effect of Carbon Content on Methanol Oxidation and Photo-Oxidation at Pt-TiO2-C Electrodes

“…Furthermore, the effect of carbon content is nearly saturated when one moves from C/Ti at = 1.5 to C/Ti at = 3. The latter finding is likely due to an increase in electrode coating thickness (and thus in methanol mass mass transfer control of the peak current at film electrodes and, thus, its square root dependence on scan rate [47][48][49]) and concentration differences (accepting a 0.5 reaction order throughout the potential range studied [50]), the maximum current density of 19 mA mgPt −1 is within the wide 1-100 mA mgPt −1 range reported for TiO2-supported Pt electrodes [8,[10][11][12]32,[51][52][53][54][55] (with most of these electrodes not exceeding 50 mA mgPt −1 [8,10,12,32,[51][52][53]55]). Figure 4C presents the voltammetric data of the same LSV experiments with those of Figure 4A,B but with the current normalized per Pt EASA, as determined by CO electrodesorption experiments and/or (when clear voltammetry could be obtained, e.g., at Pt/C and (Pt-Ru)/C electrodes) by H desorption experiments (not shown here).…”

“…The latter finding is likely due to an increase in electrode coating thickness (and thus in methanol mass transfer limitations) that offsets the increase in Pt EASA as the C content increases beyond that corresponding to C/Ti at = 1.5. Nevertheless, correcting for scan rate differences (adopting partial mass transfer control of the peak current at film electrodes and, thus, its square root dependence on scan rate [47][48][49]) and concentration differences (accepting a 0.5 reaction order throughout the potential range studied [50]), the maximum current density of 19 mA mg Figure 4A presents the stabilized (typically, the third scan) linear sweep voltamograms for methanol oxidation, recorded under near-steady-state conditions (potential scan rate of 5 mV s −1 ) at Pt-TiO2-C electrodes of varied C content while Figure 4B presents results at commercial Pt/C and (Pt-Ru)/C electrodes. The Pt mass-specific current density has a high practical value but, since it depends on a number of parameters (Pt EASA, coating thickness, and carbon adsorption capacity), it bears little mechanistic information about catalyst performance.…”

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.…”

“…[11,12] Metal oxides are widely employed as supporting material due to their super chemical stability under acidic and oxidative conditions. [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. [22] It has been confirmed that precious metal catalysts possess enhanced catalytic performances after deposited on Mn 3 O 4 .…”