Methane oxidation over supported Pd catalysts prepared by magnetron sputtering

While magnetron sputtering has been used to deposit metals onto a range of solid substrates, its application to produce porous heterogeneous catalysts in powder form is relatively unstudied. Here, magnetron sputtered Pd heterogeneous catalyst powders were prepared using a shaker operated at optimal experimental settings to give uniform coverage of the powders, and tested in the abatement of exhaust emissions in natural gas fuelled engines via the oxidation of methane. Pd nanoparticles were deposited onto alumina, titania and zeolite supports, in powder form. X-ray diffraction confirmed that the characteristic structure of each support was maintained following sputtering. The quantity of Pd increased (a) with deposition time and (b) as a function of support in the order alumina < zeolite < titania. The methane oxidation activity, measured as the temperatures at which 10% and 50% conversions were observed, T-10 and T-50, increased with Pd content for each support and was most active over zeolite catalysts despite a greater amount of Pd present on titania. Overall, the findings demonstrate that magnetron sputtering is a viable method to prepare active precious metal based catalyst powders. Furthermore, this rapid one-step process is complete after 10-20 min deposition time and avoids any metal salt impurities or the need for solvent as required in traditional synthesis methods.

Automated summary

Magnetron sputtering was used to prepare Pd heterogeneous catalyst powders for the abatement of exhaust emissions in natural gas fuelled engines. The study found that the quantity of Pd deposited increased with deposition time and varied with the support material. The methane oxidation activity of the catalysts also increased with Pd content, with zeolite catalysts showing the highest activity despite having a greater amount of Pd present on titania.