Significant Acceleration of Photocatalytic CO₂ Reduction at the Gas‐Liquid Interface of Microdroplets**

Abstract

Solar‐driven CO2 reduction reaction (CO2RR) is largely constrained by the sluggish mass transfer and fast combination of photogenerated charge carriers. Herein, we find that the photocatalytic CO2RR efficiency at the abundant gas‐liquid interface provided by microdroplets is two orders of magnitude higher than that of the corresponding bulk phase reaction. Even in the absence of sacrificial agents, the production rates of HCOOH over WO3 ⋅ 0.33H2O mediated by microdroplets reaches 2536 μmol h−1 g−1 (vs. 13 μmol h−1 g−1 in bulk phase), which is significantly superior to the previously reported photocatalytic CO2RR in bulk phase reaction condition. Beyond the efficient delivery of CO2 to photocatalyst surfaces within microdroplets, we reveal that the strong electric field at the gas‐liquid interface of microdroplets essentially promotes the separation of photogenerated electron‐hole pairs. This study provides a deep understanding of ultrafast reaction kinetics promoted by the gas‐liquid interface of microdroplets and a novel way of addressing the low efficiency of photocatalytic CO2 reduction to fuel.

Ti4+ Ions-Doped Metal–Organic Framework (MOF-74) for Photoreduction of Carbon Dioxide

“…In recent decades, the substantial rise in atmospheric CO 2 levels, primarily attributed to the extensive utilization of fossil fuels, has led to critical environmental challenges linked to global warming. − These repercussions encompass the thawing of polar ice caps, escalating sea levels, ocean acidification, severe weather occurrences, and enduring alterations in climate patterns. Immediate measures are imperative to diminish CO 2 discharges and shift toward sustainable methodologies to safeguard our planet and forthcoming generations. − To tackle these urgent issues, the utilization of photocatalysis for converting CO 2 into valuable fuels has emerged as a promising technological solution.…”