Doping techniques generally serve as effective means for tailoring the physicochemical properties of a target compound. In this work, we successfully co-doped La/Fe into Ruddlesden-Popper (RP) compound Sr₂TiO₄ and performed a detailed investigation on the crystal structure, morphology, optical absorption and photocatalytic hydrogen production reactions after doping. Our findings suggest that La/Fe co-doping slightly expand the unit cell of Sr₂TiO₄ while maintains the structure lamination. Incorporating La/Fe into Sr₂TiO₄ efficiently reduces the band gap and the level of band gap reduction can be controlled by varying the amounts of dopants. La/Fe co-doping significantly improves the photocatalytic properties of Sr₂TiO₄ under both full range (λ ≥ 250 nm) and visible light illumination (λ ≥ 420 nm). A fivefold enhancement in hydrogen production rate (∼106.2 μmol/h) is seen in sample Sr_1.9La_0.1Ti_0.9Fe_0.1O₄ (x = 0.1). Efficient photocatalytic hydrogen production under visible light illumination (λ ≥ 420 nm) is also achieved in sample Sr_1.7La_0.3Ti_0.7Fe_0.3O₄ (x = 0.3) with AQE as high as ∼1.18% at 420 nm. DFT calculations confirm the critical role of Fe in reducing the band gap of Sr₂TiO₄ by forming additional spin-polarized bands (SPB). The anisotropic charge transportation in Sr₂TiO₄ is also verified by our calculations as both conduction band minimum (CBM) and valence band maximum (VBM) are buried in TiO₆ octahedron layers. The 2D charge transportation properties are particularly useful for photocatalytic reactions since interlayer charge recombination is essentially prevented.

掺杂技术通常用作调整目标化合物的理化性质的有效手段。在这项工作中，我们成功地将La / Fe共掺杂到Ruddlesden-Popper（RP）化合物Sr ₂ TiO _4中，并对掺杂后的晶体结构，形态，光吸收和光催化制氢反应进行了详细的研究。我们的发现表明，La / Fe共掺杂可稍微扩展Sr ₂ TiO _4的晶胞，同时保持结构层压。将La / Fe掺入Sr ₂ TiO _4中有效地减小了带隙，并且可以通过改变掺杂剂的量来控制带隙减小的程度。La / Fe共掺杂可显着改善Sr ₂ TiO ₄在全范围（λ≥250 nm）和可见光照明（λ≥420 nm）下的光催化性能。在样品Sr _1.9 La _0.1 Ti _0.9 Fe _0.1 O ₄（x = 0.1）中，产氢速率提高了五倍（〜106.2μmol/ h ）。在样品Sr _1.7 La _0.3 Ti _0.7 Fe _0.3 O _4中也能在可见光照射下（λ≥420 nm）有效地产生光催化氢（x = 0.3），在420 nm处的AQE高达〜1.18％。DFT计算证实了Fe通过形成额外的自旋极化带（SPB）在减少Sr ₂ TiO ₄的带隙中的关键作用。我们的计算也验证了Sr ₂ TiO _4中的各向异性电荷传输，因为导带最小值（CBM）和价带最大值（VBM）都埋在TiO ₆八面体层中。二维电荷传输性质对于光催化反应特别有用，因为基本上可以防止层间电荷重组。