Carbon monoxide and methanol oxidation at platinum catalysts supported on ordered mesoporous carbon: the influence of functionalization of the support

Abstract

The influence of different functionalization treatments of the support on the electrocatalytic activity towards CO and methanol oxidation at platinum nanoparticles deposited on ordered mesoporous carbons (OMC) has been studied for the first time. Before deposition of the metal, the carbon support was functionalized applying several procedures, with the purpose to generate oxygenated groups for anchoring the Pt nanoparticles by the formic acid (FM) and borohydride (BM) reduction methods. Good dispersion of the catalyst was obtained in all cases. It has been shown that particle size, and consequently the lattice parameter and metal surface area, depends on the functionalization treatment employed. CO and methanol electrooxidation was studied at all prepared catalysts applying cyclic voltammetry. It was observed that CO stripping occurs at more negative potentials (around 0.10-0.15 V) with these supports with respect to Vulcan XC-72 supported catalysts, and the best results for both methods were achieved with OMC functionalized with concentrated nitric acid for 0.5 h. This carbon support presents a higher amount of oxygenated groups without the loss of the ordered structure. In situ infrared studies have been performed for the first time with this type of catalyst, showing that the effect of the carbon support on the CO oxidation potential is similar to the presence of a second metal as Ru under the same experimental conditions. Methanol electrooxidation is also dependent on the nature of the support, as proved from both cyclic voltammetry and chronoamperometry. In this case, results depend on the method of nanoparticles preparation and seem to be better for BM.

Pt nanoparticles interacting with graphitic nitrogen of N-doped carbon nanotubes: Effect of electronic properties on activity for aerobic oxidation of glycerol and electro-oxidation of CO

“…Although oxidative modification may reduce the electron density of Pt on NCNTs, the lower onset potential was measured over Pt on oxidized carbons at similar Pt4f 7/2 (0) BE. This is probably due to the effect of oxygencontaining groups, which promote the oxidation of CO ads [56][57][58]. The preceding catalytic results clearly show the effectiveness of implanting nitrogen functionality on tuning the electronic structure of CNTs-supported Pt catalysts, by which the catalytic properties can be controlled.…”

Ethanol oxidation activity and structure of carbon-supported Pt-modified PdSn-SnO2 influenced by different stabilizers

“…A clean surface is recovered in the second cycle coinciding with the voltammogram in the base electrolyte. Common behaviour described in the literature [35] was observed for the three catalysts. From Fig.…”

Electrocatalysis Using Porous Nanostructured Materials

“…commercial Pt/C (E-TEK) % 0.5 % 0.15 1 [28] commercial Pt/C (E-TEK) % 0.6 % 0.1 1 [6] hard templating with silica opal, CVD for 2 h at 1000 8C % 0.45 % 0.4 1 [28] hard templating with SBA-15, CVD for 1 h at 900 8C % 0.55 % 0.3 1 [6] hard templating with SBA-15, CVD for 60 min at 500 8C and graphitization at 850 8C % 0.55 % 0.63 1 [16] hard templating with SBA-15, wet impregnation, functionalization in 2 m HNO 3 for 0.5 h % 0.6 0.5 [7,20] ChemPhysChem www.chemphyschem.org supports (pore size: % 3.5 [6] and % 70 nm, [28] respectively) had a higher electrocatalytic activity towards methanol oxidation than standard catalysts. This results from better mass transport of the reactants and products due to higher spatial distribution of platinum particles on the mesoporous material.…”

“…This results from better mass transport of the reactants and products due to higher spatial distribution of platinum particles on the mesoporous material. [7,20] This short summary of OMCs as one example of a porous nanostructured catalyst support for methanol oxidation shows that the characteristics of the carbon support for platinum catalysts have great impact on electrochemical properties in methanol oxidation. Moreover, Calvillo and co-workers reported that functionalization with HNO 3 to create oxygen groups at the surface of OMC improved the performance of methanol oxidation due to better spatial distribution and anchoring of the platinum particles on the support.…”