Smart Bifunctional Sb Se Nanorods for Integrated Water Purification: Insoluble Liquid Separation and Photoelectrochemical Degradation.

Antimony selenide (Sb Se ) nanostructures enable bifunctional water purification by a single membrane through i) physical separation of water-insoluble oil and ii) photoelectrocatalytic degradation of water-soluble organic compounds. Sb Se nanorods with exposed surfaces of {h 0 0} and {h 0 l} planes exhibit superhydrophobicity (water contact angle of ≈159°) owing to extremely low surface energy of those dangling-bond-free van der Waals planes. Based on crystallographic understanding, superhydrophobic Sb Se nanorods were produced on a mesh-type substrate for utilization as a membrane for physical water/oil separation. Sb Se exhibited an optimal photocathodic response with p-type electrical conductivity under visible light along the longitudinal crystal direction. This indicated that the nanorods could be used as photoelectrocatalytic material for chemical water purification. A smart membrane with Sb Se nanostructures was proposed as a candidate for integrated water purification that can simultaneously accomplish water/oil separation and photoelectrocatalytic degradation of organic compounds in wastewater. Linear sweep voltammetry measurements of the Sb Se -membrane showed cathodic photocurrent generation (up to approximately 10 mA cm at 0 V vs. reversible hydrogen electrode), which was enough to reduce O to an oxygen radical (O ) for degradation of methyl orange. Consequently, solar-driven integrated water purification was demonstrated for the first time by using a single material with a dual function of superhydrophobicity and photoactivity.