Enhanced Overall Water Splitting Over Barium Titanate by Predoping‐Controlled Scandium Incorporation and Facet Formation

This is the authors' abstract. We don't add key points for this paper.

Barium titanate (BaTiO 3 ) was recently shown to function as a photocatalyst for overall water splitting after Al 3+ and Sc 3+ introduction during flux treatment and cocatalyst loading. Here, Sc 3+ was instead introduced during the solid‐state reaction used to prepare the BaTiO 3 precursor before flux treatment. At the same nominal Sc 3+ content of 1.0 mol%, the predoped sample was more active than the previously reported postdoped counterpart. Optimization gave the highest activity at 2.5 mol%, with apparent quantum yields of 37.3% at 365 nm and 46.4% at 350 nm. XRD and UV–visible diffuse reflectance analyses showed no major changes in the average crystal structure or bandgap energy, whereas Raman spectroscopy indicated a modest modification of the local bonding environment around the B site. High‐magnification SEM showed that Sc 3+ predoping progressively promoted cuboidal and truncated‐cuboidal particles with well‐defined low‐index faces, whereas the postdoped sample exhibited a more heterogeneous morphology. The optimized sample maintained its activity for 12 h. Comparison with Mg 2+ , Y 3+ , La 3+ , and intentionally added Al 3+ at a fixed nominal loading suggested that compatibility with B‐site substitution and favorable particle‐shape evolution are important factors in dopant selection.