Catalytic hydrogen combustion using platinum supported on anodized aluminium oxide adhered to metallic aluminium

Abstract

The implementation of catalytic hydrogen combustion (CHC) can mitigate the dependence on solid fuel combustion typically used in Sub-Saharan Africa as a means of heating. However, low-cost and readily available materials for catalyst fabrication are relatively unexplored. Considering the economic constraints regarding platinum group metals generally used for CHC, the cost of support materials and its functionalization as catalyst support has to be minimized. Typically, materials such as silicon carbide foam, extruded aluminium oxide-based ceramics, and titanium oxide mesh/sintered plates are used to withstand the high temperatures associated with CHC. In this paper, nanostructured anodized aluminium oxide (AAO) was synthesized as the support material via the anodization of high purity (>99%) aluminium (Al). The AAO layer intimately adhered to a metallic Al core acted as a thermal conduit to disperse heat throughout the catalyst. Platinum (Pt), considered as the reactive metal, was deposited to the AAO as nanoparticles with a diameter of approximately 19.3 nm. The CHC reaction proceeded spontaneously on the surface of the Pt/AAO catalyst. A combustion temperature of408 ± 18 °C was maintained for 70 h at a 100 normal (N) mL min-1 hydrogen flow rate. The Pt-particles showed a relatively appreciable increase in particle size (from 19.3 nm to 25.0 nm), but the significance thereof was not evident during the 70 h CHC procedure.