A special rGO/BiOI/rGO sandwich structure was fabricated, which showed an excellent visible-light photoelectrocatalytic activity much higher than BiOI/rGO and BiOI. Photocatalytic activity depended on charge separation, charge injection and effective light absorption. The charge separation efficiency and the charge injection efficiency of rGO/BiOI/rGO were quantified to be much higher than that of BiOI/rGO and BiOI. So the remarkably enhanced photoelectrocatalytic performance was attributed to the significant enhancement in charge separation and charge injection resulted from more electron transfer channels due to the upper layer and underlayer rGO in the sandwich structure. However, the effective light absorption was not improved since the light absorption efficiency of rGO/BiOI/rGO was almost the same as that of BiOI and BiOI/rGO, although the incorporation of rGO broadened the light absorption range and enhanced the light absorption intensity. This work provided a deep insight for the construction of novel rGO-based photocatalysts with hierarchical nanoarchitectures exhibiting excellent photoelectrocatalytic performances.

制备了特殊的rGO / BiOI / rGO夹心结构，显示出优异的可见光光电催化活性，远高于BiOI / rGO和BiOI。光催化活性取决于电荷分离，电荷注入和有效的光吸收。定量rGO / BiOI / rGO的电荷分离效率和电荷注入效率要远远高于BiOI / rGO和BiOI。因此，由于夹层结构中的上层和下层rGO产生了更多的电子传输通道，从而使电荷分离和电荷注入显着增强，从而显着增强了光电催化性能。但是，由于rGO / BiOI / rGO的光吸收效率几乎与BiOI和BiOI / rGO的光吸收效率相同，因此有效光吸收没有得到改善，尽管rGO的引入拓宽了光吸收范围并增强了光吸收强度。这项工作为具有新颖的基于rGO的光催化剂的构建提供了深刻的见解，该光催化剂具有表现出优异的光电催化性能的分层纳米结构。