The Ba₅Ta₄O₁₅-Ba₃Ta₅O₁₅-BaTa₂O₆ heterojunction was synthesized for the first time at ambient pressure and mild temperatures without further need of calcination. By systematically adjusting the synthesis parameters, the composition of the composite could be tailored. Detailed Rietveld refinement revealed the highest amount of by-phases for the non-calcined sample with around 12% of Ba₃Ta₅O₁₅ and 12% of BaTa₂O₆, respectively. Ba₅Ta₄O₁₅ represented the main phase for all samples. The non-calcined heterojunction showed the highest activity in photocatalytic hydrogen production with 2360 mol h⁻¹m⁻² corresponding to 1180 mol h⁻¹ without any co-catalyst. A Rh-Cr₂O₃ co-catalyst was photodeposited on all samples depending on the surface area for overall water splitting. All samples were active in overall water splitting. This novel synthesis strategy paves the way towards a general low-cost and energy-saving synthesis route to achieve highly crystalline and highly active metal oxide semiconductor photocatalysts.

在环境压力和温和温度下首次合成Ba ₅ Ta ₄ O ₁₅ -Ba ₃ Ta ₅ O ₁₅ -BaTa ₂ O ₆异质结，而无需进一步煅烧。通过系统地调节合成参数，可以调整复合材料的组成。详细的Rietveld精炼显示，未煅烧样品分别具有约12％的Ba ₃ Ta ₅ O ₁₅和12％的BaTa ₂ O ₆的副相数量最多。Ba ₅ Ta ₄ O ₁₅代表所有样本的主要阶段。未煅烧的异质结在光催化制氢中显示最高活性，为2360mol h ^-1 m ^-2对应于1180没有任何助催化剂的mol h ^-1。根据整个水分解的表面积，将Rh-Cr ₂ O ₃助催化剂光沉积在所有样品上。所有样品均在总水分解中起作用。这种新颖的合成策略为通向低成本和节能的合成路线铺平了道路，以实现高结晶度和高活性的金属氧化物半导体光催化剂。