Tuning metal-support interaction and oxygen vacancies of ceria supported nickel catalysts by Tb doping for n-dodecane steam reforming

摘要

Hydrogen is a green and efficient energy carrier that can be applied directly in fuel cell system. On-board/on-site hydrogen production for a portable fuel cell is urgently required, and catalytic steam reforming of liquid hydrocarbons is a promising pathway. In this context, Ni catalysts supported on various Tb-doped ceria were synthesized by a citric-acid-assisted sol-gel method. The textural and physicochemical properties of the fresh and spent catalysts were characterized by different techniques including XRD, N-2 physical adsorption, H-2-TPR, H-2-TPD, TEM, SEM, XPS, EPR, TG and Raman. Catalytic performance of the as-prepared catalysts was evaluated in steam reforming of n-dodecane. The conversion of n-dodecane and hydrogen production rate were measured at LHSV of 10 ml/g(cat).h and H2O/C = 2 and 4 in a fixed-bed tubular reactor. The reaction data showed that Tb dopant affected both the conversion of n-dodecane and the gas product composition. The origins of the improved performance by Tb doping were investigated, in which the moderate interaction between metal and support, highly dispersed Ni particles, increased basicity sites and abundant surface oxygen vacancies play key roles.