(182b) Atomic Layer Deposition Nano-Engineered Ni/Al2O3 Catalyst for Bi-Reforming of Methane | AIChE

(182b) Atomic Layer Deposition Nano-Engineered Ni/Al2O3 Catalyst for Bi-Reforming of Methane

Authors 

Liang, X. - Presenter, Washington University in St. Louis
Jin, B., Missouri University of Science and Technology
Wang, K., Missouri University of Science and Technology
Yu, H., Missouri University of Science and Technology
CeOx-overcoated Ni/Al2O3 catalysts were prepared by atomic layer deposition (ALD) for bi-reforming of methane (BRM), as the combination of dry reforming of methane (DRM) and steam reforming of methane (SRM). Ni nanoparticles were deposited on alpha-Al2O3 nanoparticles by ALD, followed by deposition of non-stoichiometric CeOx thin films on Ni/ Al2O3 particles by ALD, which constructed a beneficial Ni-CeOx interface and modified the catalyst property. Ascribed to the unique ALD growth mode, a high amount of Ce(III) and oxygen vacancies existed in the ALD-deposited CeOx overcoating. A reduction process before the BRM reaction contributed to the further reduction of Ce(IV) to Ce(III), resulting in more oxygen vacancies. The oxygen vacancies at the Ni-CeOx interface enabled a high rate of CO2 activation and enabled the balance between the activation of CO2 and H2O for BRM. Due to its oxygen vacancies as activation sites for CO2 and H2O, CeOx ALD overcoating significantly improved the activity of Ni/Al2O3 catalyst and achieved a better control in the H2/CO ratio with a suitable ratio of H2O/CO2/CH4 feed. CeOx overcoatings enhanced the reducibility of Ni(II) sites and assisted in preventing Ni from oxidation during the BRM reaction. Less carbon deposition was achieved by the Ni/Al2O3 catalyst with CeOx overcoating as ascribed to its better reactant activation capacity.