过渡金属掺杂的双钙钛矿Ba_(2)InNbO_(6)的光催化分解水性能

Transition Metal Doped Double Perovskite Ba_(2)InNbO_(6)as Efficient Photocatalyst for Water Splitting

双钙钛矿材料由于其丰富的化学组成及晶体结构被认为是一类优良的光催化材料,但大多数双钙钛矿氧化物仅表现出紫外光催化活性。因此,本文通过过渡金属离子Fe、Cr、Ni等掺杂调控双钙钛矿化合物Ba_(2)InNbO_(6)的能带结构,期望实现高效的可见光催化活性,并研究掺杂元素对晶体结构、微观形貌、表面状态等物化性质的影响。结果表明,过渡金属能够成功地引入到双钙钛矿的Ba_(2)InNbO_(6)的In位点,并能拓宽材料的可见光吸收范围。此外,过渡金属的引入改变了材料表面亲水性,晶胞发生收缩,颗粒尺寸增大。与Ba_(2)InNbO_(6)相比,过渡金属掺杂的样品光催化析氢活性得到了极大的改善。其中,Ba_(2)In_(0.9)Fe_(0.1)NbO_(6)在全范围照射(λ≥250 nm)下的析氢量最高,达到了15.8μmol,并且在可见光(λ≥420nm)照射下的析氢速率为2.71μmol/h,其对应的表观量子效率为0.016%。

Double perovskite materials are considered to be a class of excellent photocatalytic materials due to their rich chemical composition and crystal structure,but most double perovskite oxides only exhibit ultraviolet photocatalytic activity.In this paper,the band structure of the double perovskite compound Ba_(2)InNbO_(6)is adjusted by doping with transition metal ions Fe,Cr,Ni,etc.,and it is expected to achieve high-efficiency visible light catalytic activity.The effect of doping elements on the crystal structure,microscopic morphology,surface state and other physical and chemical properties are investigated.The results show that transition metals can be successfully introduced into the In site of Ba_(2)InNbO_(6)of double perovskite,and can be used as an effective dopant to broaden the visible light absorption range.In addition,the introduction of transition metals into the unit cell causes significant crystal shrinkage,and the surface hydrophilicity has also been greatly improved.Compared with Ba_(2)InNbO_(6),the photocatalytic hydrogen evolution activity of transition metal doped samples has been greatly enhanced.Among them,Ba_(2)In_(0.9)Fe_(0.1)NbO_(6)shows the highest activity for hydrogen evolution under full-range irradiation(λ≥250 nm),reaching 15.8μmol,and the hydrogen evolution rate under visible light(λ≥420 nm)irradiation is 2.71μmol/h corresponding apparent quantum efficiency is 0.016%.