Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
ACS Appl Mater Interfaces. 2016 Mar 23;8(11):7165-72. doi: 10.1021/acsami.6b00907. Epub 2016 Mar 11.
This work attempted to synthesize heterojunctioned nanoparticles consisting of a transition metal and Cr on powdered SrTiO3, an n-type semiconductor exhibiting photocatalytic activity for overall water splitting. This was performed via band gap irradiation of SrTiO3 (λ > 300 nm) in an aqueous methanol solution containing a transition metal precursor and K2CrO4. The resulting multicomponent nanoparticles were examined as promoters for photocatalytic overall water splitting. Among the transition metals examined, Au and Pd became effective promoters for overall water splitting upon codeposition of Cr. In the case of Au, which is stable in its metallic state, the resulting (Au+Cr) nanoparticles had a core/shell structure consisting of metallic Au (the core) and amorphous Cr2O3 (the shell), similar to Au/Cr2O3 prepared by a stepwise photodeposition method. However, when using a core transition metal with a tendency to form an oxide, such as Pd, the nanoparticles had different morphologies and electronic states, depending on the proportion of Cr. In the case of a combination of Pd and Cr, the photocatalytic activity for overall water splitting was strongly dependent on the structure and electronic state of the (Pd+Cr) multicomponent cocatalyst. Increasing the proportion of Cr was found to suppress the reverse reaction (that is, H2-O2 recombination), an effect that is not realized when employing a conventional impregnation method.
这项工作试图在 SrTiO3（一种表现出光催化整体水分解活性的 n 型半导体）粉末上合成由过渡金属和 Cr 组成的异质结纳米粒子，该方法通过 SrTiO3（λ>300nm）在含有过渡金属前体和 K2CrO4 的水甲醇溶液中的能带隙辐照来实现。将所得的多组分纳米粒子用作光催化整体水分解的促进剂进行了研究。在所研究的过渡金属中，Cr 共沉积后 Au 和 Pd 成为整体水分解的有效促进剂。在 Au 的情况下，由于其处于金属状态而稳定，所得的（Au+Cr）纳米粒子具有由金属 Au（核）和非晶 Cr2O3（壳）组成的核/壳结构，类似于通过分步光沉积方法制备的 Au/Cr2O3。然而，当使用倾向于形成氧化物的核过渡金属（例如 Pd）时，纳米粒子的形态和电子态取决于 Cr 的比例。在 Pd 和 Cr 的组合的情况下，整体水分解的光催化活性强烈依赖于（Pd+Cr）多组分共催化剂的结构和电子状态。发现增加 Cr 的比例可以抑制逆反应（即 H2-O2 重组），而当使用常规浸渍法时则无法实现该效果。
