Study of Carbon Monoxide Oxidation on Mesoporous Platinum

Abstract

H(1) mesoporous platinum surfaces formed by electrodeposition from lyotropic liquid crystalline templates have high electroactive surface areas (up to 60 m(2) g(-1)) provided by the concave surface within their narrow (≈2 nm diameter) pores. In this respect, they are fundamentally different from the flat surfaces of ordinary Pt electrodes or the convex surfaces of high-surface-area Pt nanoparticles. Cyclic voltammetry of H(1) mesoporous Pt films in acid solution is identical to that for polycrystalline Pt, suggesting that the surfaces of the pores are made up of low-index Pt faces. In contrast, CO stripping voltammetry on H(1) mesoporous Pt is significantly different from the corresponding voltammetry on polycrystalline Pt and shows a clear prewave for CO oxidation and the oxidation CO at lower overpotential. These differences in CO stripping are related to the presence of trough sites where the low-index Pt faces that make up the concave surface of the pore walls meet.

A Selective Blocking Method To Control the Overgrowth of Pt on Au Nanorods

“…The nanoparticles with the lowest Pt coverage exhibit the lowest activity, with a broad wave followed by another wave at more positive potentials. The nanoparticles prepared by the selective blocking method produce CVs with a sharp peak centered at more negative potentials, reminiscent of similar measurements on polycrystalline Pt, 35 and with higher overall charge than for CVs of the other samples. The sharpness of the peak, along with the CVs of the clean NR surfaces, indicates that the selective blocking method yields NRs with more extended regions of Pt surface.…”

On the design of Pt based catalysts. Combining porous architecture with surface modification by Sn for electrocatalytic activity enhancement

“…Furthermore, the CO stripping is a powerful technique for the study of the surface morphology and structure. In addition, CO stripping is a convenient method to obtain an accurate estimation of the electroactive surface area [26,41].…”

“…the porous radio can be adjusted by the choice of the appropriated surfactant, and additional porosity can be introduced by the selection of the applied potential). The resulting catalysts possess an extremely concave mesoporous surface, and this characteristic may, by itself, affect the CO electrooxidation reaction [26].…”

Structure sensitivity and nanoscale effects in electrocatalysis

“…In agreement with this idea, a recent paper by Esterle et al has suggested that the concave curvature of nanoporous platinum electrodes is responsible for the low-potential CO stripping peak on such electrodes. 62 As mentioned, a much-debated issue in CO oxidative stripping has been the role of surface diffusion of CO from the less active terrace sites to the more active step sites. Clearly, the issue of surface diffusion will apply to class IV reactions in general.…”