Enhanced Stability and Activity of Nitrogen-Doped Carbon Nanotube-Supported Ni Catalysts for Methane Dry Reforming

The dry reforming of methane (DRM) converts two greenhouse gases, CH4 and CO2, into H2 and CO, offering a crucial technological pathway for reducing greenhouse gas emissions and producing clean energy. However, the reaction faces two main challenges: high activation energy barriers require high temperatures to drive the reaction, while sintering and carbon deactivation at high temperatures are common with conventional nickel-based catalysts, which severely limit the further development of the methane dry reforming reaction. In this study, a nitrogen-doped carbon nanotube-loaded nickel catalytic system (Ni/NCNT) was developed to overcome the challenges caused by limited active sites while maintaining the stable structure of the Ni/CNT system. Ni/NCNT catalysts were prepared using different nitrogen precursors, and the impact of the mixing method on catalytic performance was examined. Characterization using H2-TPR, XPS, and TEM revealed that nitrogen doping enhanced the metal-support interaction (MSI). Additionally, pyridine nitrogen species synergistically interact with nickel particles, modulating the electronic environment on the carbon nanotube surface and increasing catalyst active site density. The Ni/NCNT-IU catalyst, prepared with impregnated urea, exhibited excellent stability, with methane conversion decreasing from 85.0% to 82.9% over 24 h of continuous reaction. This study supports the use of non-precious-metal carbon-based catalysts in high-temperature catalytic systems, which is strategically important for the industrialization of DRM and the development of decarbonized energy conversion.