Hierarchical porous carbon supports: construction, mechanism, and catalytic performance as efficient microreactors for methanol steam reforming

Abstract

In this study, hierarchical porous carbon (HPC) supports were prepared from disposable chopsticks by KOH activation, followed by loading Cu/Ce active components for methanol steam reforming (MSR). It was found that the KOH activation conditions had a significant effect on the pore structure and surface functional groups of the HPC supports. Specifically, at a KOH impregnation ratio of 5:1 and activation time of 3 h, the prepared C₈ support exhibited a high specific surface area and a well-developed microporous structure. After impregnation with Cu/Ce, the catalysts exhibited exceptional performance in MSR, with the 20 % Cu₂/Ce₁/C₈ catalysts achieving the highest hydrogen yield of 17,753 μmol·g⁻¹·h⁻¹ at 250 °C. The catalysts were systematically characterized to correlate their structural properties with performance，and a “microporous reactor” mechanism was proposed. Specifically, the well-defined microporous architecture enhanced reactant adsorption through size-selective confinement effects, promotes efficient catalytic conversion via spatial confinement of active species, and suppresses nanoparticle agglomeration through physical immobilization within the porous matrix. This synergistic interplay of adsorption-reaction-stabilization processes significantly enhances both the catalytic activity and long-term stability of the catalysts.