Asymmetric substrate supported Ni catalysts for robust photothermal catalytic dry reforming of methane

Photothermal catalytic dry reforming of methane with CO₂ has emerged as a promising yet nascent strategy for mitigating greenhouse gas emissions and enabling clean energy conversion. However, achieving optimal performance requires advances in both catalyst design and mechanistic understanding. Herein, we adopted a double-emulsion-guided micelle assembly strategy to synthesize asymmetric supports (AMONs and AMOMs), featuring unidirectional open/closed pore channels. This distinctive architecture enabled the formation of an asymmetric catalyst configuration through ethylene glycol-assisted selective confinement of Ni nanoparticles at the open-pore termini. Compared to conventional symmetric catalysts, the optimized 5% Ni AMONs EG and 5% Ni AMOMs EG exhibited higher specific surface areas and improved metal dispersion, resulting in an abundance of active sites. Moreover, the asymmetric design strengthened the built-in electric fields, directing more photogenerated hot carriers and localized thermal energy toward reactant activation. Consequently, 5% Ni AMOMs EG achieved a remarkable H₂ production rate of 2314.2 mmol g⁻¹ h⁻¹ and sustained H₂ yields over 50 hours, outperforming symmetric counterparts and even some reported noble metal-based catalysts. This work offers a smart photothermal catalyst candidate and elucidates its structure-performance relationship, advancing photothermal catalytic technology for solar fuel production.