Computationally guided dopant discovery for boosting TiO2 catalysts in plasma-assisted non-oxidative coupling of methane

The direct conversion of methane into value-added C 2 hydrocarbons offers a promising route to mitigate climate change and reduce reliance on fossil-derived feedstocks. Plasma-assisted methane coupling enables C–H bond activation under mild, oxidant-free conditions, but plasma-only systems suffer from poor selectivity and significant carbon deposition. To overcome these challenges, heterogeneous catalysts have been explored to steer reaction pathways and suppress coke formation. Titanium dioxide (TiO 2 ), known for its coke resistance, shows promise under plasma condition but remains limited by low activity and selectivity. Here, we present a combined theoretical and experimental study to enhance the catalytic performance of TiO 2 for non-oxidative plasma-assisted methane coupling (NOCM). Density functional theory (DFT) calculations were performed to assess the effect of 3d transition metal doping (V, Cr, Mn, Fe, Co, Ni, Cu) on methane activation and C 2 product formation, followed by microkinetic modeling under plasma-relevant conditions. Vanadium emerged as the most effective dopant for enhancing CH 4 activation and C 2 H 6 production. Based on these findings, V-doped TiO 2 catalysts were synthesized and tested in a DBD plasma reactor, showing improved CH 4 conversion and C 2 H 6 yield compared to pristine TiO 2 . Additionally, the yields of heavier C 3 –C 9 hydrocarbons increased, and coke formation was significantly suppressed. Overall, this study highlights a rational catalyst design strategy that maintains TiO 2 ’s coke resistance while enhancing activity and selectivity for sustainable methane valorization under plasma condition. • 3d transition metal-doped TiO 2 was screened using DFT to enhance plasma-assisted non-oxidative coupling of methane. • Hydrogen adsorption energy was identified as a key descriptor to predict catalytic activity and selectivity trends. • DFT-based microkinetic modeling revealed that V-doped TiO 2 exhibits superior performance compared to pure TiO 2 . • Experimental results confirmed that V doping enhances methane conversion and ethane yield compared to pristine TiO 2 .