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

Abstract

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 catalyst iteration 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 unique structure facilitated a ‘confined/unconfined’ asymmetric Ni configuration through ethylene glycol-assisted selective confinement at the open-pore termini. Compared to conventional symmetric catalysts, 5% Ni AMONs EG and 5% Ni AMOMs EG exhibited higher specific surface areas and improved metal dispersions, leading to abundant active sites. Moreover, the asymmetric configuration enhanced built-in electric fields, directing more photogenerated hot carriers and localised thermal energy for reactant activation. Consequently, H₂ production rates reached 2314 mmol·g⁻¹·h⁻¹ for the optimized 5% Ni AMOMs EG, with a sustained H₂ yields over 12 hours, surpassing 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.