Concave structure of Cu2O truncated microcubes: PVP assisted {100} facet etching and improved facet-dependent photocatalytic properties

In this work, a concave structure of Cu2O truncated microcubes with {100} facet erosion has been successfully synthesized by a facile top-down etching method. Air and PVP were employed as an etchant and a shape controller agent, respectively. For the facet-selective capping of PVP on Cu2O {111} planes, the traditional relatively low energy {100} facets of Cu2O truncated microcubes would be selectively etched along their [100] zone axis in a top-down manner. The {100} facet etched Cu2O concave truncated microcubes exhibited highly improved photocatalytic activities (2.15 and 1.21 times, respectively) compared to that of the basic structure and the {111} facet etched samples on the degradation of Congo red (CR), displaying distinct facet-dependent photocatalytic characteristics, excellent stability and reusability. This work not only builds an efficient photocatalyst, but also provides a novel method to fabricate a variety of architectures with low energy facets etched and highly active crystal planes exposed, which is extremely important for the improvement of catalytic activities.