Plasma-enabled catalytic dry reforming of CH4 into syngas, hydrocarbons and oxygenates: Insight into the active metals of γ-Al2O3 supported catalysts

Dry reforming of CH4 (DRM) using a plasma-enabled catalytic process is an appealing approach for reducing greenhouse gas emissions while producing fuels and chemicals. However, this is a complex process that is influenced by both catalysts and discharge plasmas, and low energy efficiency remains a challenge for this technology. Here, we developed a water-cooled dielectric barrier discharge (DBD) reactor for plasma DRM re-actions over supported catalysts (Ni/gamma-Al2O3, Ag/gamma-Al2O3 and Pt/gamma-Al2O3) prepared via plasma-modified impregnation. Results show that metal loading on gamma-Al2O3 enhanced the basic nature of the catalysts and pro-moted the formation of discharge channels and reactive species. The maximum conversion of CO2 (21.4 %) and CH4 (27.6 %) was obtained when using Ag/gamma-Al2O3. The basic nature of the catalytic materials dominated CO2 conversion, whereas the properties of the catalyst and discharge plasma determined CH4 conversion. The highest selectivity of hydrogen (-34.5 %) and carbon-containing gas products (-81.0 %) were attained when using the noble metal catalysts (Ag/gamma-Al2O3 and Pt/gamma-Al2O3), while the highest total selectivity of liquid products (14.1 %) was achieved in the presence of Ni/gamma-Al2O3. Compared with gamma-Al2O3, the supported catalysts demonstrated higher stability, especially for Ag/gamma-Al2O3 and Pt/gamma-Al2O3, which also provided higher energy efficiency for gas conversion and product formation.

Automated summary

Dry reforming of CH4 (DRM) using a plasma-enabled catalytic process is an attractive method for reducing greenhouse gas emissions. In this study, a water-cooled dielectric barrier discharge (DBD) reactor was developed for plasma DRM reactions over supported catalysts. The results showed that metal loading enhanced the basic nature of the catalysts and promoted the formation of discharge channels and reactive species. Noble metal catalysts exhibited higher selectivity for hydrogen and carbon-containing gas products. The supported catalysts demonstrated higher stability and energy efficiency compared to unsupported catalysts.