Ligand modulation of active center to promote lead-free Cs2AgInCl6 photocatalytic CO2 reduction

Metal halide perovskites (MHP) are potential candidates for the photocatalytic reduction of CO 2 due to their long photogenerated carrier lifetime and charge diffusion length. However, the conventional long-chain ligand impedes the adsorption and activation of CO 2 molecules in practical applications. Here, a ligand modulation technology is employed to enhance the photocatalytic CO 2 reduction activity of lead-free Cs 2 AgInCl 6 microcrystals (MCs). The Cs 2 AgInCl 6 MCs passivated by Oleic acid (OLA) and Octanoic acid (OCA) are used for photocatalytic CO 2 reduction. The results show that the surface defects and electronic properties of Cs 2 AgInCl 6 MCs can be adjusted through ligand modulation. Compared with the OLA-Cs 2 AgInCl 6 , the OCA-Cs 2 AgInCl 6 catalyst demonstrated a significant improvement in the catalytic yield of CO and CH 4 . The CO and CH 4 catalytic yields of OCA-Cs 2 AgInCl 6 reached 171.88 and 34.15 µmol g −1 h −1 which were 2.03 and 12.98 times higher than those of OLA- Cs 2 AgInCl 6 , and the total electron consumption rate of OCA-Cs 2 AgInCl 6 was 615.2 µmol g −1 h −1 which was 3.25 times higher than that of OLA-Cs 2 AgInCl 6 . Furthermore, in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs 2 AgInCl 6 MCs induced by ligand modulation. This study illustrates the potential of lead-free Cs 2 AgInCl 6 MCs for efficient photocatalytic CO 2 reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.