CO_2 dry reforming of CH_4 with Sr and Ni co-doped LaCrO_3 perovskite catalysts

摘要

Catalysts La0.8-xSrxCr0.15Ni0.5O3(x = 0, 0.1, 0.2 and 0.3; P-80, P-71, P-62 and P-53) are prepared and reduced (R-80, R-71, R-62 and R-53) in H-2 for CO2-dry reforming of methane (CO2-DRM). P-80, P-71 and P-62 are single-phase perovskite; P-53 contains additional NiO and SrCrO4. Ni particles are exsolved in R-80, R-71 and R-62 with a strong interfacial interaction; whereas those in R-53 are produced by NiO reduction. Increasing Sr concentration increases basicity and oxygen vacancy concentration of the support. R-53 demonstrates the highest conversion of CH4 and CO2 below 650 degrees C, which decreases to the lowest above 650 degrees C due to carbon deposition, while R-62 shows the highest performance with CH4 and CO2 conversions on the level of 90% at 800 degrees C because of the strong exsolved Ni particle/support interfacial interaction and the high basicity and oxygen vacancy concentration of the support. The performance of R-62 increases with the decrease of gas hourly space velocity (GHSV) from 1.2 to 0.3 x 10(4) ml g(-1) h(-1), and remains stable at 750 degrees C and 0.3 x 10(4) ml g(-1) h(-1) with conversions of CH4 and CO2 near 90% and selectivities of H-2 and CO above 95%.