Asymmetric Porous Catalyst Structures for Low-Temperature Photocatalytic Dry Reforming of Methane

Abstract

Recent advances in the photocatalytic activation of dry reforming of methane (DRM: CO2 + CH4 -> 2CO + 2H2) at low temperature and ambient pressure have generated considerable interest as a promising route to convert greenhouse gases into valuable synthetic gas (syngas). While detailed studies have revealed the mechanisms involved in photocatalytic DRM at metal-semiconductor interfaces, less attention has been devoted to how high-surface-area semiconductor supports may enhance such conversions. Here, we structure triblock terpolymer self-assembly directed sol-gel-derived transition metal oxide (Ta2O5 or TiO2) supports of Rh-loaded photocatalysts into various equilibrium and nonequilibrium derived porous morphologies and show how they modulate single-pass conversion, total production rate, and material efficiency. Supported by in-depth materials characterization, flow, and optics simulations rationalizing observed trends, results reveal record catalyst performance. Our work suggests that asymmetric pore structures simultaneously optimizing mass transport and surface area may be well-suited to maximize photocatalyst performance.