Exploring the Relationship between Effective Mass, Transient Photoconductivity, and Photocatalytic Activity of Sr_xPb_1–xBiO₂Cl (x = 0–1) Oxyhalides

Owing to the rapid advancement in computer hardware and quantum chemical software, chemists can relatively easily calculate the electronic properties of semiconducting photocatalysts. However, these computed parameters do not always govern the overall photocatalytic activity of semiconductors because of the complexity of photochemical reactions and other undesired factors. Here, we explore the relationship between the effective mass of the charge carrier (m*) calculated by density functional theory (DFT), transient pseudophotoconductivity maximum (φΣμmax) determined by time-resolved microwave conductivity (TRMC), and photocatalytic activity for layered oxyhalide photocatalysts (PbBiO2Cl and SrBiO2Cl). DFT calculations reveal that the m* values of the electron and hole increase substantially upon substituting Pb by Sr in the oxyhalide (SrxPb1–xBiO2Cl, x = 0–1); this is accompanied by significant anisotropy of m* in the in-plane direction. Notably, the φΣμmax from the TRMC and O2-evolution rates of SrxPb1–xBiO2Cl solid solutions tend to decrease with x, consistent with the change in m*. This work encourages efficient exploration of potential semiconducting photocatalysts based on transient spectroscopies and computed parameters.