Lattice Boltzmann method to simulate photocatalytic reduction of CO₂ over PCN-601 coated on transparent porous substrate

Abstract

Photocatalysis offers a promising approach to convert solar energy and CO₂ into clean chemical energy, such as methane (CH₄) and carbon monoxide (CO), contributing to carbon neutrality. This study proposes a lattice Boltzmann method to solve radiation transport within transparent porous substrates for photocatalytic CO₂ reduction. Numerical simulations of mass transfer, radiation, and reaction kinetics are in good agreement with experimental results. The influence of triply periodic minimal surfaces (TPMS) as porous substrates on photocatalytic efficiency is investigated, identifying substrate thickness as the dominant variable affecting performance. At reduced thicknesses, porosity and surface area gain importance by enhancing light absorption and fluid flow. Notably, at 10 pores per inch (PPI), a 2 mm thick Schwarz D substrate demonstrates comparable photocatalytic performance to a 7 mm thick gyroid. However, at 30 PPI, it leads to diminished performance despite similar porosity by reducing thickness. These results suggest that a PPI value around 10 optimizes the efficiency for photocatalytic CO₂ reduction.