Electrochemical performance of carbon-supported Pt(Cu) electrocatalysts for low-temperature fuel cells

Synthesis and Evaluation of PtNi Electrocatalysts for CO and Methanol Oxidation in Low Temperature Fuel Cells

“…A Pt lattice contraction was found for Pt(Cu)/C catalysts prepared in the same form as in our present paper, thus indicating some alloying degree between Pt and Cu, forming a fcc PtCu alloy structure [43,60]. As this is not the case from the results shown in Figure 2, we may conclude that a PtNi alloy is not being formed in the present conditions.…”

“…We feel that the position of the Pt peaks in Figure 2 could be explained in two forms: i) the Pt lattice is slightly expanded because it has grown on the hexagonal Ni core and ii) this peak is the summation of the contribution of small hexagonal Ni crystallites together with the dominant Pt cubic phase. A Pt lattice contraction was found for Pt(Cu)/C catalysts prepared in the same form as in our present paper, thus indicating some alloying degree between Pt and Cu, forming a fcc PtCu alloy structure [43,60]. As this is not the case from the results shown in Figure 2, we may conclude that a PtNi alloy is not being formed in the present conditions.…”

“…In this study, Pt(Ni)/C and PtRu(Ni)/C electrocatalysts on Vulcan XC72R carbon were synthesized using different proportions of metals by chemical reduction of a Ni precursor with NaBH 4 and subsequent deposition of Pt from a Pt(IV) precursor. It is then expected that the final structure was a Ni-rich core covered by a Pt-rich shell, similarly to the Pt(Cu)/C and PtRu(Cu)/C catalysts prepared earlier by the authors, which led to good onset potentials for the CO oxidation and the MOR [14,17,42,43]. The catalysts obtained were evaluated in a three-electrode cell for the oxidation reactions of CO and methanol in sulfuric acid.…”

“…The hydrogen desorption charges after the consecutive cycling of Pt(Ni)/C and PtRu(Ni)/C 3:1 decreased by 8.8 and 3.0% respectively, with comparable values of 10.5 and 5.0% for 8:1. This can be due to the surface Pt restructuration because the anodic limit of the cyclic voltammograms is well in the potential range of Pt oxidation and therefore, the catalysts can be considered rather stable [43], thus suggesting that Ni is reasonably covered by a Pt shell.…”

“…Many basic research scientists are currently focusing their attention to obtain catalysts with precursors that provide good electrocatalytic activity using small amounts of noble catalytic metals to lower costs [33][34][35][36]. Thus, alloying Pt with other transition metals such as Cu, Fe, Ni and Co, has allowed obtaining catalysts with better performance due to favorable electronic effects together with decreasing the amount of precious metals [14,17,18,28,29,31,33,35,[37][38][39][40][41][42][43][44][45][46].…”