Photoelectrocatalytic CO2 reduction using stable lead-free bimetallic CsAgBr2 halide perovskite nanocrystals

We report on the fabrication and systematic characterization of highly stable lead-free CsAgBr<inf>2</inf> perovskite nanocrystals (PNC) processed at room temperature without the involvement of any organic ligand. X-ray diffraction (XRD) measurements and Rietveld analysis of the data reveal that the synthesized perovskites are in the orthorhombic phase with space group Cmcm. The optical properties of the CsAgBr<inf>2</inf> PNC are analyzed by UV–Vis absorbance and photoluminescence spectra. Morphological studies are performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Additionally, the high degree of structural stability of the PNC was reaffirmed by time-dependent XRD profiles, and the thermal stability was studied by Thermogravimetric analysis (TGA). PNC exhibit excellent air stability for up to six months and thermal stability up to 200 °C. Furthermore, we demonstrate superior photoelectrocatalytic CO<inf>2</inf> reduction using CsAgBr<inf>2</inf> PNC with around ∼14 μmol g⁻¹h⁻¹ of CO yield and 50% Faradic efficiency.