Light oils from methane homologation over hierarchically porous TiO₂/SiO₂ hybrid catalyst for a non-thermal plasma

Significant effort has been dedicated to the conversion of methane (CH₄) into more valuable chemicals, but its direct conversion into longer-chain hydrocarbons remains challenging. Herein, we develop hierarchically porous TiO₂/SiO₂ (HP-TiO₂/SiO₂) catalysts with adjustable Ti/Si molar ratios for plasma-assisted CH₄ conversion to light oils including gasoline-range and diesel-range hydrocarbons in the C₅–C₁₆ range. By exploiting interfacial interactions between block copolymer and homopolymer constituents, precise control over macro- and mesoporous structures is achieved. The hierarchical porosity promotes plasma penetration, CH₄ activation and intermediate conversion. The Ti/Si ratio influences chain-growth probability, increasing selectivity for gasoline- and diesel-range hydrocarbons, reminiscent of Fischer-Tropsch synthesis but without high-temperature CH₄ reforming. Density functional theory calculation demonstrates the coke-resistant properties of HP-TiO₂ catalysts by lowering CH₃ desorption energy and increasing the activation barrier for dehydrogenation. This work provides insights into non-thermal plasma-activated catalyst optimizations for CH₄ conversion, and offers prospects for direct synthetic fuel and chemical production.