Rational one-pot synthesis of ternary PtIrCu nanocrystals as robust electrocatalyst for methanol oxidation reaction

Platinum–Copper Bimetallic Nanodendritic Electrocatalyst on a TiO2-Based Support for Methanol Oxidation in Alkaline Fuel Cells

“…As illustrated in Figure a, apart from typical diffraction peaks of the tungsten-modified TiO 2 nanomaterials, the XRD profile of the as-obtained electrocatalyst showed three peaks at 2θ degrees of 40.03, 46.43, and 67.97°, corresponding to the index to the fcc structure that shifted slightly to positive angles in comparison with the pure Pt (Figure b). This could be interpreted due to a lattice contraction of the fcc Pt lattices by the incorporation of smaller Cu atoms, similar to what has been reported. ,, Additionally, the diffraction peaks of the fcc Cu metal (JCPDS 04-0836) were not observed in the XRD patterns of the Pt 3 Cu NDs/Ti 0.7 W 0.3 O 2 catalyst, indicating the development of the bimetallic Pt 3 Cu nanoalloy onto the tungsten-modified TiO 2 nanosupport. TEM images in Figure c,d exhibited the dendritic-like morphology of the bimetallic Pt 3 Cu nanoalloy with a diameter of about 3 nm.…”

“…Figure a shows the deconvoluted Pt 4f spectra with the most intense peaks of the zerovalent state (Pt 0 ) (Pt 4f 5/2 and Pt 4f 7/2 at 73.94 and 70.54 eV, respectively) and the weak pair of the Pt 2+ species (Pt 4f 5/2 and Pt 4f 7/2 at 75.24 and 71.66 eV, respectively). The appearance of the Pt 2+ states in the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst could be interpreted due to the formation of PtO or Pt­(OH) 2 , which was assigned to the oxidized surficial platinum in the air or the unreacted precursor. ,− Analogously, the deconvoluted Cu 2p spectra in Figure b displayed the most strong doublet peaks of the zerovalent state (Cu 0 ) (Cu 2p 1/2 and Cu 2p 3/2 at 952.18 and 932.22 eV, respectively) and other weak doublet peaks of ionic Cu (Cu 2+ ) (Cu 2p 1/2 and Cu 2p 3/2 at 954.42 and 934.81 eV, respectively), which is in agreement with reported values. ,, Furthermore, the Pt 4f spectrum of the metallic Pt state of the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst was shifted to negative binding energy in comparison with the Pt 4f spectrum of the metallic Pt (Pt 0 ) in the commercial C-supported Pt (NPs) catalyst . Likewise, the binding energy of Cu 2p of the metallic Cu state in the as-obtained catalyst was also observed to be lower than the Cu metal (932.60 eV for Cu 2p 3/2 ) .…”

“…After the CA test, the Pt 3 Cu NDs/Ti 0.7 W 0.3 O 2 catalyst retained the highest electrocatalytic activity compared to other catalysts, demonstrating the best CO-tolerance and electrocatalytic stability for MOR in alkaline media of the dendritic-like Pt 3 Cu nanoalloy onto the tungsten-modified TiO 2 nanosupport. The impressive CO-tolerance capability of the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst compared with the C-supported Pt (NPs) could be assigned to the combinatory effects of platinum, copper, and W-modified TiO 2 nanosupport, weakening the bonding strength of the adsorbed species on the catalyst surface during the MOR. , For the W-modified TiO 2 -supported Pt (NDs) catalyst, the great CO antipoisoning of the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst could be assigned to the beneficial effect of Cu, generating adsorbed oxygenated species and thus facilitating methanol oxidation by the formation of HCOO – as intermediate products, resulting in the CO 2 formation rather than through the way, with the formation of CO as intermediate species, which was strongly adsorbed on the active sites on the electrocatalyst surface. , Furthermore, the high CO-tolerance of the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst in comparison with the Pt 3 Cu NDs/TiO 2 catalyst could be assigned to the introduction of W, providing more important hydroxyl groups at less potential than platinum, promoting the oxidation of the adsorbed CO on the electrocatalyst surface. , …”

“…First, alloying Pt with Cu could offer a propitious arrangement of the structure of platinum atoms at the nanocrystal surface resulting in more active crystallographic facets or a favorable Pt–Pt interatomic distance for MOR . Additionally, the addition of Cu improved the formation of adsorbed oxygenated species, facilitating the MOR according to the formation way of intermediate HCOO – species resulting in the formation of CO 2 rather than the generation route of the CO species, which was strongly adsorbed on the platinum surface-active sites, inducing the CO-poisoning effect. , Second, the dendrite-like nanostructure displayed the high surface area and large density of low-coordinated atoms, providing more surface-active sites in comparison with the spherical-like nanostructure, facilitating accessibility for methanol molecules of the electrocatalyst surface. ,, Third, the introduction of W in the anodic Pt-based catalyst resulted in the promotional effect for the electro-oxidation of methanol. , In addition, the superior electrochemical corrosion resistance of the mesoporous tungsten-modified TiO 2 nanomaterials resulted in the enhanced MOR durability of the electrocatalyst. Finally, the synergistic and electron effects between the dendritic-like Pt 3 Cu nanoalloy and mesoporous tungsten-modified TiO 2 nanosupport, weakening the bonding strength of the carbonaceous products on the catalyst surface, contribute to the enhanced MOR performance of the W-modified TiO 2 -supported Pt 3 Cu (NDs) catalyst.…”

One-Step Microwave-Assisted Synthesis of PtNiCo/rGO Electrocatalysts with High Electrochemical Performance for Direct Methanol Fuel Cells

“…Pt 1-x-y Ir x Ni y nanocrystals were synthesized by a one-step process at room temperature and showed excellent tolerance to poisoning and stability [ 24 ]. In addition, ternary PtIrCu nanocrystals exhibit high durability and toxicity tolerance due to their large surface area, composition, and strain effects [ 25 ]. Lee et al [ 26 ] developed a carbon-loaded PtRuNi/C ternary electrocatalyst.…”