Perovskite Photocatalytic CO(2) Reduction or Photoredox Organic Transformation?

Metal‐halide perovskites have been explored as photocatalysts for CO(2) reduction. We report that perovskite photocatalytic CO(2) reduction 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). CO(2) reduction in organic solvents must be studied with extra care because photoredox organic transformations can produce orders of magnitude higher rate of CO or CH(4) than is typical for CO(2) reduction routes. Though CO(2) reduction 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.