A study of refractory carbon deposits on Ni/Al ₂ O ₃ catalysts for dry reforming of methane

When investigating carbonaceous species on a catalyst via temperature‐programmed techniques, both the nature of the carbons and the possibility of the catalytic reaction of carbonaceous species should be considered. Here we examined CH 4 decomposition (carbon deposition from CH 4 ) and the reverse Boudouard reaction (carbon elimination by CO 2 ) on the Ni/Al 2 O 3 catalyst using sequential temperature‐programmed experiments. Carefully considering both the location and characteristics of carbon deposits formed on the Ni/Al 2 O 3 catalyst, we conclude that carbons located on the Al 2 O 3 support are challenging to remove by CO 2 regardless of their nature, indicating the importance of support activity in reducing carbon deposits. In this study, the incorporation of cesium (Cs) into Al 2 O 3 shows no effect on the prevention of carbon deposition from CH 4 but does show an enhancement of carbon removal via the reverse Boudouard reaction, resulting in less coke formation on the Ni/Cs doped Al 2 O 3 catalyst than the Ni/Al 2 O 3 catalyst by 17 % for the dry reforming of methane.