Experimental study of Ni/MgO catalyst in carbon dioxide reforming of toluene, a model compound of tar from biomass gasification

An experimental study of Ni/MgO solid solution catalyst in CO2 reforming of toluene was conducted in this paper. Experimental parameters were reduction temperature, reaction temperature, CO2/toluene mole ratio, and toluene feed rate.An optimized reduction temperature was 700 °C to obtain the sufficient surface Ni as well as avoid the severe sintering of Ni particles. Either higher reaction temperatures or higher CO2/toluene mole ratios made Ni/MgO more stable and efficient. Ni/MgO at 550 °C and a high CO2/toluene mole ratio of 28 had a better activity with less coke than that at 570 °C but low CO2/toluene mole ratios (≤14), which suggested the activation of carbon intermediates from the dissociation of toluene by abundant oxidizing CO2 species played a crucial role in having a better catalytic performance. At a high toluene feed rate (0.48 ml/h), Ni/MgO had an inferior activity due to the comparatively insufficient active Ni; moreover, it had a worse stability because of a large amount of coke.

Graphical abstractExperimental study for toluene reforming with CO2 on Ni/MgO catalyst.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Tar reforming with CO2 was used to minimize CO2 release from gasification. ► Experimental study of Ni/MgO catalyst was studied for a possible application. ► The sufficient surface Ni amount was fundamental to have a high activity. ► The quick oxidation of surface carbon by CO2 was crucial for catalytic stability. ► Two types of coke under high toluene feed rate were detected by CO2-TPO test.