Smart Bifunctional Sb₂Se₃ Nanorods for Integrated Water Purification: Insoluble Liquid Separation and Photoelectrochemical Degradation

Abstract

Antimony selenide (Sb2Se3) 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. Sb2Se3 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 Sb2Se3 nanorods were produced on a mesh‐type substrate for utilization as a membrane for physical water/oil separation. Sb2Se3 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 Sb2Se3 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 Sb2Se3‐membrane showed cathodic photocurrent generation (up to approximately 10 mA cm−2 at 0 V vs. reversible hydrogen electrode), which was enough to reduce O2 to an oxygen radical (O2.−) 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.

Progressive NO2 Sensors with Rapid Alarm and Persistent Memory‐Type Responses for Wide‐Range Sensing Using Antimony Triselenide Nanoflakes

“…In addition, for an extremely low gas concentration detection, the sensitivity values in the initial state before gas adsorption maintained a stable and constant resistance level of 0%, and was associated with the prominent humidity insensitivity, which is expected for Sb 2 Se 3 nanoflakes owing to their intrinsic hydrophobicity. [ 43 ] In turn, NO 2 gas adsorption decreased the resistance and increased the sensitivity of the sensor during the first cycle (Figure 5b). Here, a spontaneous desorption of the gas molecules restoring the resistance occurred simultaneously at lower rates than the adsorption and restored the resistance, resulting in an increase in the total sensitivity.…”

“…[ 42 ] Based on these specific characteristics, Sb 2 Se 3 nanoflake‐based gas sensors were fabricated through a simple thermal transfer process on two‐terminal electrode substrates (Mo/SiO 2 ) with a finger‐type configuration ( Figure a), by which Sb 2 Se 3 showed a high vapor pressure at low temperature, enabling a simple nanostructuring process. [ 43 ] The anisotropic Sb 2 Se 3 crystal structure exhibited a specific quasi‐2D structure consisting of 1D ribbon‐like structures bounded by van der Waals forces. From the ribbon‐like structure, the { 0k0} planes covalently bonded between the Sb and Se atoms preferentially generated a polar surface containing numerous dangling bonds.…”

“…A detailed description of the procedure was provided in a previous report. [ 43 ] Morphological investigations of the Sb 2 Se 3 nanoflakes were conducted using field‐emission SEM (JSM‐6700F, 10 kV). The crystallographic properties of the crystalline Sb 2 Se 3 phases were investigated using TEM (JEM‐2100F) and XRD (Bruker AXS D8 Discover with a Cu Kα radiation source).…”

In situ synthesis and improved photoelectric performances of a Sb2Se3/β-In2Se3 heterojunction composite with potential photocatalytic activity for methyl orange degradation

“…In general, sulfide/selenide photocatalysts can have excellent photocatalytic performance [53][54][55][56]. Considering the remarkable photocurrent density and the excellent stability of the SI-10% sample, it was tested for photodegradation of MO dye.…”