A hybrid catalyst of perovskite nanocrystals and a 2D MXene enables efficient solar-driven CO ₂ conversion. Combining CsPbBr ₃ with partially oxidized Ti ₂ N MXene gives tunable CH ₄ /CO selectivity, showing promising sustainable photothermal fuel production. Created with Google Gemini – via Google Cloud.

The development of lead‐free perovskites as environmentally sustainable materials has gained significant attention for their applications in solar cells and photocatalysis. In this study, Cs ₂ PtCl ₆ and Cs ₂ PtBr ₆ vacancy‐ordered double perovskites are synthesized via a hydrothermal method and evaluated as ligand‐free photocatalysts for solar‐driven water splitting, targeting the oxygen evolution reaction (OER). Structural characterization confirms their cubic phase, and ultraviolet‐visible diffuse reflectance spectroscopy reveals optical bandgaps of 2.17 eV for Cs ₂ PtCl ₆ and 1.94 eV for Cs ₂ PtBr ₆ . Theoretical calculations based on density of states analysis confirms their semiconductor behavior. Photocatalytic studies show that Cs ₂ PtBr ₆ exhibits superior O ₂ evolution rates (368.9 μmol g ⁻¹ h ⁻¹ ) compared to Cs ₂ PtCl ₆ (237.4 μmol g ⁻¹ h ⁻¹ ), attributed to its favorable electronic structure. Also, photoluminescence (PL) studies reveals that Cs ₂ PtBr ₆ exhibits lower PL intensity and a longer emission lifetime (2.5 μs) compared to Cs ₂ PtCl ₆ (1.3 μs). Long‐term stability tests highlight moderate photostability, with Pt ⁴⁺ reduction due to precipitation of Pt ⁰ under prolonged irradiation or reuses. This research highlights the potential of Cs ₂ PtX ₆ perovskites for efficient, sustainable OER catalysis while identifying challenges related to structural stability and charge recombination.

The development of synthetic procedures for preparing metal nanoparticles with controlled size using sunlight opens new avenues toward more sustainable methods with lower energy consumption. Herein, we propose the use of double-vacancy halide perovskites as precursors for engineering highly crystalline and small platinum nanoparticles (< 3 nm) under simulated sunlight irradiation, using low concentration of methanol as sacrificial agent at room temperature. The formation of Pt NP was dependent on the methanol concentration impacting in the final Pt particle size distribution and time formation. After purification, this narrow sized Pt NP were employed for the methanol reforming reaction, showing excellent activity after 4 h and high selectivity toward hydrogen production (4.18 mmol·h −1 of H 2 ), along with other carbon products such as CO (2.26 mmol·h −1 ), CH 4 (0.54 mmol·h −1 ), CO 2 (0.28 mmol·h −1 ), and C 2 species (0.17 mmol·h −1 ).