Characteristic of cold sprayed catalytic coating for hydrogen production through fuel reforming

Cold spray was employed as a novel method to prepare NiO/Al2O3 primary steam reforming catalyst coating for hydrogen production. The coating microstructure was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) before and after reforming reactions. The catalytic coating performance was examined through methane steam reforming (SRM) in a microreactor. Results showed that NiO/Al2O3 coating was successfully deposited on the stainless steel substrate by cold spray. The thickness of the coating was about 50 μm. It presented a rough surface and porous structure. Since temperature of the cold spray process is low, no phase changes occurred to NiO/Al2O3 during deposition. However the particle size in the coating became smaller compared with the feedstock due to its smashing. It was found that the cold-sprayed catalytic coating was active for SRM at high space velocity although filamentous carbon was formed on its surface. After reaction there was no obvious peeling off of the coating indicating a good bonding between the coating and substrate.