화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.42, No.10, 6598-6609, 2017
Effect of mineralizers for preparing ZrO2 support on the supported Ni catalyst for steam-CO2 bi-reforming of methane
Supported Ni catalysts on ZrO2 towards steam-CO2 bi-reforming (SCBR) of methane for the production of synthesis gas were synthesized by the hydrothermal process with different mineralizers followed by L-arginine ligand-assisted incipient wetness impregnation (HT-LA-IWI) method. The effect of type and amount of mineralizers for preparing ZrO2 supports on the nature of supports and supported Ni catalysts, as well as on the catalytic properties and structure-performance relationship were investigated. Results show that the catalytic performance is strongly dependent on the morphology and textural of ZrO2 support notably affected by the type and amount of mineralizer. The supported Ni catalyst on the ZrO2 prepared by using sodium acetate (molar ratio of sodium acetate/zirconium, N-SAc/Zr = 0.5) as mineralizer (Ni/ZrO2 (SAc0.5)) shows much higher catalytic activity than the one on ZrO2 prepared by using sodium carbonate (molar ratio of sodium carbonate/zirconium, N-SC/Zr = 0.5) as a mineralizer (Ni/ZrO2 (SC0.5)), ascribed to higher Ni dispersion and smaller average crystallite size of Ni. With respect to both activity and stability, the sodium acetate can be selected as a suitable mineralizer for the preparation of excellent ZrO2 support. Furthermore, the increasing N-SAc/Zr from 0.5 to 2.0 leads to an increase in surface area but a decrease in pore diameter and pore volume, which endows the Ni/ZrO2 (SAc2.0) catalyst with much larger average crystallite size of Ni but much worse Ni dispersion than Ni/ZrO2 (SAc0.5). As a result, Ni/ZrO2 (SAc2.0) shows much lower catalytic activity than Ni/ZrO2 (SAc0.5). Moreover, the Ni/ZrO2 (SAc2.0) catalyst shows worse Ni sintering resistance than Ni/ZrO2 (SAc0.5) owing to its weaker Ni-ZrO2 interaction confirmed by H-2-TPR results, which endows it with lower catalytic stability although it has higher coke deposition resistance. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.