Confining Bismuth-Halide Perovskite in Mesochannels of Silica Nanomembranes for Exceptional Photocatalytic Abatement of Air Pollutants

Spatially confined photocatalysis has emerged as a viable strategy for the intensification of various redox reactions, but the influence of confined structure on reaction behavior is always overlooked in gas-solid reactions. Herein, we report a nanomembrane with confining Cs3Bi2Br9 nanocrystals inside vertical channels of porous insulated silica thin sheets (CBB@SBA(perpendicular to)) for photocatalytic nitric oxide (NO) abatement. The ordered one-dimensional (1D) pore channels with mere 70 nm channel length provide a highly accessible confined space for catalytic reactions. A record-breaking NO conversion efficiency of 98.2 % under a weight hourly space velocity (WHSV) of 3.0x106 mL g-1 h-1, as well as exceptionally high stability over 14 h and durability over a wide humidity range (RH=15-90 %) was realized over SBA(perpendicular to) confined Cs3Bi2Br9, well beyond its nonconfined analogue and the Cs3Bi2Br9 confine in Santa Barbara Amorphous (SBA-15). Mechanism studies suggested that the insulated pore channels of SBA(perpendicular to) in CBB@SBA(perpendicular to) endow concentrated electron field and enhanced mass transfer that render high exposure of reactive species and lower reaction barrier needs for & sdot;O2- formation and NO oxidation, as well as prevents structural degradation of Cs3Bi2Br9. This work expands an innovative strategy for designing efficient photocatalysts for air pollution remediation. Nanoconfined photocatalysis promises to achieve challenging chemical transformation, but the influence of confined structure has been ignored. Here, we propose a confinement model by encapsulating Cs3Bi2Br9 into one-dimensional insulated channels of porous silica nanomembranes, rendering the concentrated electric field, high exposure of & sdot;O2- and enhanced mass transfer for exceptional photocatalytic nitric oxide (NO) abatement.image