†Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
‡Photocatalysis international Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan.
ACS Appl Mater Interfaces. 2015 Jul 15;7(27):14638-43. doi: 10.1021/acsami.5b01555. Epub 2015 Jul 6.
K4Nb6O17 (BG: 3.67 eV) and Na2W4O13 (BG: 3.12 eV) layered oxide photocatalysts with wide band gaps were treated with a molten AgNO3 to substitute K+ and Na+ with Ag+, resulting in red-shifts of absorption edges in diffuse reflectance spectra. A part of Na+ ions in the interlayer of Na2W4O13 was substituted with Ag+ ions by the molten AgNO3 treatment with keeping the layered structure. Both Ag(I)-substituted K4Nb6O17 and Na2W4O13 showed photocatalytic activities for O2 evolution from aqueous solutions containing a sacrificial reagent utilizing the absorption bands newly formed by the Ag(I)-substitution. Notably, the Ag(I)-substituted Na2W4O13 produced O2 under visible light irradiation. When ball-milled Na2W4O13 was treated with a molten AgNO3, the Ag(I)-substitution rate increased. The Ag(I)-substituted Na2W4O13 with ball-milling showed higher photocatalytic activity for O2 evolution than that without ball-milling. Z-schematic water splitting proceeded under visible light irradiation by combining the Ag(I)-substituted Na2W4O13 of an O2-evolving photocatalyst with Ru-loaded SrTiO3 doped with Rh of a H2-evolving photocatalyst.
K4Nb6O17（BG：3.67 eV）和 Na2W4O13（BG：3.12 eV）这两种具有宽禁带的层状氧化物光催化剂用熔融的 AgNO3 处理，用 Ag+取代 K+和 Na+，导致漫反射光谱中吸收边缘红移。用熔融的 AgNO3 处理，Na2W4O13 层间的一部分 Na+离子被 Ag+离子取代，同时保持层状结构。Ag(I)取代的 K4Nb6O17 和 Na2W4O13 都表现出利用 Ag(I)取代形成的新吸收带，从含有牺牲试剂的水溶液中光催化产生 O2 的活性。值得注意的是，Ag(I)取代的 Na2W4O13 在可见光照射下产生 O2。当用熔融的 AgNO3 处理球磨的 Na2W4O13 时，Ag(I)取代率增加。与未球磨的相比，经过球磨的 Ag(I)取代的 Na2W4O13 对 O2 产生的光催化活性更高。通过将 O2 产生光催化剂 Ag(I)取代的 Na2W4O13 与 H2 产生光催化剂负载 Ru 的 Rh 掺杂 SrTiO3 结合，在可见光照射下进行 Z 型水分解。
