Collocated Measurements of Light‐Absorbing Organic Carbon in PM 2.5 : Observation Uncertainty and Organic Tracer‐Based Source Apportionment

Xie, Mingjie; Peng, Xiang; Shang, Yue; Yang, Li; Zhang, Yuanyuan; Wang, Yuhang; Liao, Hong

doi:10.1029/2021JD035874

Abstract Metal‐halide perovskites have been explored as photocatalysts for CO₂reduction. We report that perovskite photocatalytic CO₂reduction in organic solvents is likely problematic. Instead, the detected products (i.e., CO) likely result from a photoredox organic transformation involving the solvent. Our observations have been validated using isotopic labeling experiments, band energy analysis, and new control experiments. We designed a typical perovskite photocatalytic setup in organic solvents that led to CO production of up to ≈1000 μmol g⁻¹ h⁻¹. CO₂reduction in organic solvents must be studied with extra care because photoredox organic transformations can produce orders of magnitude higher rate of CO or CH₄than is typical for CO₂reduction routes. Though CO₂reduction is not likely to occur, in situ CO generation is extremely fast. Hence a suitable system can be established for challenging organic reactions that use CO as a feedstock but exploit the solvent as a CO surrogate.

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