Enhanced Photodegradation of Methyl Orange Synergistically by Microcrystal Facet Cutting and Flexible Electrically-Conducting Channels

By performing precise facet cutting during hydrothermal synthesis, single-morphological and uniform-sized octahedral and cubic Cu2O microcrystals respectively with {111} and {100} facets are synthesized and subsequently encapsulated with reduced graphene oxide (rGO). Electrochemical impedance spectroscopy shows that the rGO/Cu2O polyhedral composite has excellent conductivity, indicating that rGO can serve as a flexible electrically conducting channel. On account of the accumulation of a large amount of photoexcited electrons on the {111} facets of the octahedrons and efficient electron transfer to the rGO sheet, photodegradation of methyl orange by the rGO/Cu2O octahedral composite is enhanced by a factor of 4 compared to both bare Cu2O octahedrons and rGO-encapsulated cubes with hole accumulation on the {100} facets, and the stability of the rGO/Cu2O octahedrons is obviously improved due to no direct touch with water molecules in comparison with Cu2O microcrystals without rGO wrap reported previously. This work shows that the combination of crystal facet cutting and conducting channels is an effective strategy to design new composites with enhanced photocatalytic properties.