The effect of the calcination temperature on the physicochemical properties and catalytic activity in the dry reforming of methane over a Ni–Co/Al2O3–ZrO2 nanocatalyst prepared by a hybrid impregnation-plasma method

Abstract

The effect of the calcination temperature on the physicochemical properties and catalytic performance of a plasma treated Ni–Co/Al₂O₃–ZrO₂ nanocatalyst was studied in the dry reforming of methane. According to the XRD, FESEM, TEM, EDX dot-mapping, BET and XPS characterizations, the optimum calcination temperature was found to be 600 °C in which the maximum surface area, agglomeration free morphology and well-dispersion of the active phase was found. In the nanocatalyst calcined at 600 °C, a narrow particle size distribution of nanoparticles with an average particle size of 21.4 nm has been observed. The Ni/Al ratio from the XPS analysis which shows the Ni dispersion on alumina was 13.4%. The calcined Ni–Co/Al₂O₃–ZrO₂ nanocatalyst at 600 °C was depicted to have the best activity in the conversion of feed and product yield due to its well defined morphology that originated from the proper calcination temperature. The long reaction time confirmed the stability of the plasma treated Ni–Co/Al₂O₃–ZrO₂ nanocatalyst calcined at 600 °C and its ability to suppress coke deposition. The results showed that calcination after plasma treatment is an essential step and the nanocatalyst structure and its reactivity in the dry reforming of methane was strongly influenced by the calcination temperature.