Nanoporous Pt-based catalysts prepared by chemical dealloying of magnetron-sputtered Pt-Cu thin films for the catalytic combustion of hydrogen

Abstract

In this work, we prepared SiC-supported Pt-Cu thin films by magnetron sputtering for use as catalysts for the combustion of hydrogen under oxidizing conditions. We tested the catalysts as prepared and after chemical dealloying. A methodology is presented to fabricate catalytic thin films of a desired composition with tailored magnetron targets with lower Pt consumption. The deposition gas was changed to prepare columnar (Ardeposited) and closed-porous (He-deposited) films to study the effect of the microstructure on the activity. The effect of composition was also studied for the columnar samples. The as-prepared Pt-Cu thin films showed significant activity only at temperatures higher than 100°C. Dealloying permitted an increase in the activity to achieve near room-temperature activity. The dealloyed closed-porous He-deposited sample was the most active, being able to convert as much as 13.15 LH2•min -1 •gPt -1 at 70°C (Ea=1kJ.mol -1 ). This sample was preferentially dealloyed on the surface, yielding Código de campo cambiado Código de campo cambiado Código de campo cambiadoan almost pure Pt shell (96% at. Pt) and a Cu-depleted interior (71% at. Pt). This compositional inhomogeneity enabled the sample to achieve enhanced activity compared to the Ar-deposited columnar sample (with similar initial composition, but uniformly dealloyed), probably due to the compressive surface lattice strain. The dealloyed closedporous He-deposited sample was shown to be durable over five cycles.

Pd-C Catalytic Thin Films Prepared by Magnetron Sputtering for the Decomposition of Formic Acid

“…To achieve this objective, we employed a homemade target composed of a commercial C target with Pd strips in different amounts and configuration. This methodology was inspired by our previous work [ 41 ] in which we presented a cost-effective method for the fabrication of Pt-based catalytic coatings by MS. In that case, a tailored target was fabricated with a conventional Cu target on which four Pt strips were radially distributed.…”

“…PVD techniques are advantageous due to their compatibility with varied support compositions. In particular, magnetron sputtering (MS) has attracted attention for the preparation of supported nanostructured electrocatalysts [ 38 ] and catalysts for hydrogen-involving reactions, such as the hydrolysis of sodium borohydride and the catalytic combustion of hydrogen [ 39 , 40 , 41 , 42 ].…”

A hydrogen generator coupled to a hydrogen heater for small scale portable applications

“…For the flameless H 2 catalytic combustion Pt and Pd are reported as the most active catalysts which permit to initiate the reaction without ignition even at room temperature [15,[22][23]. In this work a Pt deposited catalyst was prepared on commercial SiC foam by impregnation with an ethanolic solution of H 2 PtCl 6 for a final Pt loading of 1.0 wt%.…”

Three-Dimensional Sulfite Oxidase Bioanodes Based on Graphene Functionalized Carbon Paper for Sulfite/O2 Biofuel Cells

“…[1][2][3] The development of efficient and durable catalysts for FCs has been a research hotspot for more than a decade. 4,5 Noble metal catalysts such as platinum (Pt) show high efficiency, 4,6 but are fraught with limited abundance and easy poisoning. In parallel, biological catalysts such as enzymes are promising candidates to be used for energy conversion, due to their sustainability, high catalytic activity and selectivity towards the substrates.…”