Highly Stable\nBaZrS<sub>3</sub> Chalcogenide Perovskites\nfor Photoelectrochemical Water Oxidation

Chalcogenide perovskites have emerged as potential semiconductor\nmaterials for optoelectronic devices due to their superior visible\nlight absorption and high thermal and chemical stability. Here, we\nreport BaZrS<sub>3</sub> chalcogenide perovskites-based photoelectrode\nfor photoelectrochemical water splitting (PEC). Experimental findings\nreveal that BaZrS<sub>3</sub> exhibits excellent stability in harsh\npH conditions (pH 3–13) and shows panchromatic absorption with\na band gap of 1.77 eV. Temperature-dependent impedance and Raman spectroscopy\nunveil the presence of polarons and suggest the possibility of polaron-mediated\nconduction in this material. Under 1 Sun illumination, the PEC device\nattains a maximum photocurrent density of 0.36 mA/cm<sup>2</sup> at\n0.323 V vs Ag/AgCl at pH 12 (equivalent to 0 V vs RHE), maintaining\nstability for 30 min. Notably, the photoanode exhibits remarkable\nstability before and after the photoelectrochemical reaction. BaZrS<sub>3</sub> photoanode displays high surface charge separation efficiency,\npromoting the surface oxidation reaction.