Construction and reaction characteristics of pyrochlore-supported Ni catalysts for tar steam reforming
Tar is a common by-product during the gasification of biomass and its presence largely limits the subsequent application of syngas generated. Although biomass tar could be converted into hydrogen-rich syngas by catalytic steam reforming , the frequently adopted high-activity and low-cost Ni catalysts suffer from the problem of easy deactivation as a result of carbon deposition , and more efficient and stable catalyst needs to be developed for tar removal in biomass gasification . In the work, various Ni/pyrochlore catalysts characterized with redox properties were constructed and further modified through partial replacement of A-site in support, and their reaction characteristics in toluene steam reforming were comprehensively investigated. Results show that catalysts of Ni/La 2 Ce 2 and Ni/Y 2 Ce 2 have good catalytic performance due to the strong interaction between Ni and pyrochlore. Although a small amount doping of Sr in A-site is observed to decrease Ni/pyrochlore interaction, the great promotion in surface oxygen mobility make Ni/La 1.8 Sr 0.2 Ce 2 possess the best reactivity among all catalysts studied, and the optimum operating conditions is determined to be 650 °C and S/C = 2. Moreover, Ni/La 1.8 Sr 0.2 Ce 2 is found to be very stable during toluene steam reforming, which is proved to be a result of the superior capability in resisting coke formation.
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