Production of syngas by methane dry reforming over the catalyst ZNi1-xCex: effects of catalyst calcination and reduction temperature

BACKGROUND: A nickel-based catalyst is active in the dry reforming of methane. However, the nickel-metal particles' sintering at high reaction temperatures and the rapid catalyst deactivation due to coke deposition are still significant issues. RESULTS: A series of catalysts, Ni1-xCex, was prepared by the sol-gel technique and the synthesized catalysts were used for the methane dry reforming reaction considering various parameters, such as the ceria to nickel ratio, total loading, catalyst calcination, and reduction temperature. The addition of ceria to nickel increased the CH4 and CO2 percent conversion. The catalyst 40Ni(0.75)Ce(0).(25)/Al2O3 calcined at 700 & DEG;C possessed a high conversion of CO2 and CH4. The reduced catalyst (40Ni(0.75)Ce(0.25)/Al2O3) showed better catalytic activity than the calcined catalyst. However, the reduced catalyst's performance declined due to coke deposition. The calcined catalyst was more stable than the reduced catalyst. The time-on-stream study (up to 16 h) reflected that the percent conversion and yield dropped more sharply for the reduced catalyst (% CO2 Conversion dropped: 100% to 94%) than for the calcined catalyst (% CO2 conversion dropped: 94% to 93%). The accumulation of ceria and support (alumina) increased the catalyst surface area, which improved the overall activity and stability of the catalyst. Scanning Electron Microscopy (SEM) and Raman spectroscopy analyses detected the formation of Multi Walled - Carbon Nanotubes (MW-CNT) on the used catalyst. They also show the formation of a smaller diameter of MW-CNT (60-70 nm) over the calcined catalyst than the reduced catalyst (80-139 nm). CONCLUSION: The calcined catalyst, 40Ni(0.75)Ce(0.25)/Al2O3-700 & DEG;C, was very active with high methane (91%) and CO2 (94%) conversions; also, the reduced catalyst was active and possessed high methane (88%) and CO2 (100%) conversions at low reaction temperatures. Overall, the calcined catalyst was comparatively more stable than the reduced catalyst. (C) 2022 Society of Chemical Industry (SCI).

Automated summary

A series of Ni1-xCex catalysts were prepared by the sol-gel technique and tested for the dry reforming of methane. The addition of ceria to nickel improved the conversion of CH4 and CO2. The calcined catalyst 40Ni(0.75)Ce(0.25)/Al2O3 at 700°C showed high CO2 and CH4 conversion. The reduced catalyst exhibited better catalytic activity but suffered from coke deposition.