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NiO/Al 2 O 3 catalyst coatings on stainless steel and aluminum substrates, CuO/ZnO/Al 2 O 3 catalyst coating on Al substrate have been prepared by cold spray technology for fuel reforming. Deposition behavior in coating formation has been studied. Microstructure and micro-region composition of the coatings are analyzed by SEM and EDX. Results show that the coating retains its original composition and majority porosity of catalyst feedstock. Smashing of the oxide feedstock particle plays an important role in coating formation. Original particle sizes and substrate materials affect bonding of the coating with substrate. Coke formation on NiO/Al 2 O 3 coating is not so serious most likely due to good heat conduction. Bonding strength of CuO/ZnO/Al 2 O 3 catalyst coating with Al mainly belongs to mechanical interlock and it seems lower than that of NiO/Al 2 O 3 catalyst. First layer on CuO/ZnO/Al 2 O 3 coating surface peels in reaction due to its fragile material nature. Conclusively, cold spray technology can be a successful method for functional catalyst coating fabrication for fuel reforming. [ABSTRACT FROM AUTHOR]

Abstract: Kinetics of methane steam reforming for hydrogen production has been studied through experiment in a micro-channel reactor over coating catalyst. The catalyst coating prepared by cold spray on stainless steel substrate is based on a mixture of Ni–Al oxides which is normally employed in industry for methane primary steam reforming. Two kinetic laws namely parallel as well as inverse models have been derived at atmospheric pressure, and power law type kinetics have been established using non-linear least squares optimization. With the above kinetics, simulation study has been carried out to find out temperature distribution in the micro-channel over coating catalyst at two different types of boundary conditions. The results show a quite different “cold spot” character and reactants, products distribution character in the reaction channel due to its own distinct heat and mass transfer features. The kinetics and simulation study results can be applied in aid of micro-channel reactor design, and suggestion has been proposed for catalytic coating preparation and optimization. [Copyright &y& Elsevier]

Z-scheme anatase/rutile TiO 2 /g-C 3 N 4 hybrids (denoted as LTARCN-x, x represents calcination temperature) were designed and synthesized by growing TiO 2 nanorods on the surface of g-C 3 N 4 utilizing impregnation-calcination method. Furthermore, through the etched effect of hydrochloric acid and calcination treatment, the as-prepared LTARCN-x possessed abundant pore structure and larger surface area, and the surface area of LTARCN-425 was 8.5 times than that of bulk g-C 3 N 4. Meanwhile, the g-C 3 N 4 would play a role of carrier to prevent from the aggregation of TiO 2 nanorods. In addition, under visible light irradiation, the Z-scheme heterostructure would be constructed between the rutile TiO 2 nanorod and g-C 3 N 4 nanosheet, respectively. The optimized photocatalyst LTARCN-425 exhibited a preferable activity, the photocatalytic hydrogen production rate of LTARCN-425 was about 1031 μmol g−1 h−1, and it was about 6.3 and 13.6 times than that of g-C 3 N 4 and TiO 2 , respectively. Moreover, the photocatalytic mechanism of the hydrogen production was studied intensively via designing fluorescent probe, Pt and PbO 2 deposition experiment, and the characterizations of EPR, TEM, HRTEM and XPS. [ABSTRACT FROM AUTHOR]

Abstract: 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 50μm. 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. [ABSTRACT FROM AUTHOR]