Rh/Ce0.9Pr0.1O2 catalysts supported on carbon monoliths with complex channels network design prepared by 3D printing for N2O decomposition

Abstract

Rh/Ce0.9Pr0.1O2/carbon monolith catalysts have been prepared and tested for N2O decomposition, using 3D printing technology to fabricate carbon supports with different channels geometry including conventional honeycomb design and a nonlinear channel of circular interconnections. The potential penalty in pressure drop of the advanced monolith design has been experimentally ruled out. The activity of the supported catalysts has been successfully tested under simulated N2O/He gas flow and in the presence of O2, NOx and H2O simulating the gas composition in an operating room in a hospital and in a nitric acid production plant, removing in both cases the 96 % of N2O at 375 ◦C and 400 ◦C respectively. The behaviour of the catalyst with honeycomb support is improved with the advanced support with the 3D network of nonlinear channels of circular interconnections due to the promotion of gas turbulences that diminish gas diffusion limitations generated in the honeycomb channels, allowing conversion increase by 15 %. The stability of the Rh/Ce0.9Pr0.1O2/carbon monolith catalysts was studied by TGA under air flow and the combustion occurred above 435 ◦C, indicating that the stability window is high enough for the applications tested in this study. The catalysts characterisation indicated that the active phase loaded on the carbon monoliths is located both in the channels where the reaction gases flow through and into the carbon bulk, while the amount located into the carbon bulk generates certain diffusion limitations in the catalytic tests. The accumulation of active phase in the channels is favoured by increasing the active phase loading.