Coating of FeCrAlloy foam with Rh catalysts: Optimization of electrosynthesis parameters and catalyst composition

Coating of FeCrAlloy foam cylinders with Rh-based catalysts was performed by the in situ electrosynthesis of Rh/Mg/Al hydrotalcite-type precursors on the surface of the support. The structured catalysts, obtained after calcination at 900 °C, were characterized and tested in the catalytic partial oxidation of CH4 at an oven temperature of 750 °C, by feeding diluted and concentrated CH4/O2/He gas mixtures. Electrochemical parameters (potential applied, synthesis time and supporting electrolyte) and the composition of the catalyst precursor (Rh/Mg/Al atomic ratio) were changed with the aim to optimize both the properties of the coating and catalytic performances. The sample prepared in absence of KNO3 as the supporting electrolyte at −1.2 V vs saturated calomel electrode for 2000 s yielded the catalyst with the best performances thanks to an improved coating and large amount of Rh in the outer part of the catalytic coating.

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► Electrosynthesis was used to coat FeCrAlloy foams with precursors of Rh catalysts active in the CPO of CH4.
► The potential applied, synthesis time and composition of the solution were modified.
► The application of a −1.2 V for 2000 s and using a solution without KNO3 led to the best catalyst.