Al-doped SrTiO₃ synthesized in a SrCl₂ melt is among the most efficient known photocatalysts for water splitting. Although the effect of Al³⁺ incorporation has been widely discussed, the role of the molten SrCl₂ remains unclear. Herein, we report the influence of the molten SrCl₂ treatment and a comparable molten KCl treatment on the surface structure and composition of SrTiO₃ using AFM and XPS. The hydrogen evolution rates of particulate Al-doped SrTiO₃ photocatalysts were measured with a parallelized and automated photochemical reactor. In SrCl₂, it is found that 3 % to 5 % of the SrTiO₃ dissolves in the melt, revealing a new hydroxyl-rich surface. The melt reacts with the alumina crucible to form Sr₃Al₂O₆, ultimately leading to the elimination of the melt. In addition, the surface potential difference between (1 0 0) and (1 1 0) surfaces increases from 0.07 V to 0.21 V after the treatment, allowing for enhanced separation of photogenerated charge carriers and leading to improved photocatalytic reactivity. When heated in KCl, the SrTiO₃ surfaces reconstruct and this changes the spatial distribution of photocathodic and photoanodic reaction sites.