Electrochemical Degradation of Refractory Pollutant Using a Novel Microstructured TiO₂ Nanotubes/Sb-Doped SnO₂ Electrode

Abstract

A novel Sb-doped SnO2 electrode featuring high oxygen evolution potential, excellent electrocatalytic performance, and long stabilitytoward electrochemical degradation of refractory organic pollutants was constructed by designing and regenerating the microstructure of the Ti substrate. Highly ordered TiO2 nanotubes (TiO2-NTs) with three-dimensional microstructure, large specific surface area and space utilization rate could be grown in situ on Ti substrate under controlled conditions, followed by being implanted with Sb-doped SnO2 through a surfactant-assisted, sol-gel method under vacuum environment. The amount of Sb-doped SnO2 and service lifetime for the constructed electrode (TiO2-NTs/SnO2) were 2.4 and 12 times as much asthose for a traditional Sb-doped SnO2 (SnO2) electrode. Moreover, the constructed electrode performed at higher oxygen evolution potential and exhibited superior electrochemical capability to that on SnO2 electrode. Compared with low TOC removal by the SnO2 electrode, the TiO2-NTs/SnO2 electrode could completely mineralize benzoic acid (BA) under the same condition. The mineralization current efficiency and the first-order kinetic constant for BA degradation at the TiO2-NTs/SnO2 electrode were 1 and 3.5 times greater than those observed for the SnO2 electrode.

A novel approach for textile dye degradation by zinc, iron–doped tin oxide/titanium moving anode

“…It is the combined effects of doping and anode motion that makes the Fe, Zn-doped SnO 2 /Ti moving anode methyl orange electro-oxidation system truly stand a class apart. This fact can be construed from the results reported further in this contribution, which are comparable with the commonly reported Ti/SnO 2 -Sb and doped SnO 2 /Ti anodes (Kong et al 2007;Raghu et al 2009;Watts et al 2008;Zhao et al 2009). …”

Using TiO2 Mesoflower Interlayer in Tubular Porous Titanium Membranes for Enhanced Electrocatalytic Filtration

“…Cyclic voltammetry (CV) curves were also recorded to examine the voltammetric charge quantity of the electrodes. Tests on accelerated service life were conducted following the procedures reported by Zhao et al [18]. The amount of coated ATO was determined by weighing the TPTM or TPTM/TMF before and after the ATO coating using a balance with a 0.1 mg [18].…”

“…A higher O ad content for TPTM/TMF/ATO helps the metal oxide (MO x ) catalyst (i.e., ATO) to form active oxygen spices with strong oxidation capabilities e.g. physisorbed ÁOH (donated as MO x (ÁOH)), which are critical for unselective and effective degradation of organic pollutants [18,20,33]. It has been reported that O ad appears to actively participate in electrochemical reactions [34].…”

“…Among the popular electrochemical catalysts (e.g. boron-doped diamond (BDD) [13], RuO 2 [14], Ti 4 O 7 [3,15], IrO 2 [16], PbO 2 [17], and Sbdoped SnO 2 (ATO) [18]), ATO is considered an excellent candidate owing to its high oxygen evolution potential (OEP), 1.8 V (vs saturated calomel electrode, SCE) [18], easy in preparation and cost efficiency. Electrocatalytic properties (e.g.…”

“…OEP and electrochemical oxidation capacity) of an ATO film are closely related to its physical properties on the substrate, such as its morphology and crystalline structure. Previous reports have demonstrated that introducing a micro/nano-structured interlayer (e.g., aligned TiO 2 nanotubes (NTs) [18][19][20], Cu nanorods (NR) [21], or TiN nanoparticles (NPs)) [22] between ATO and the titanium substrate is an effective way to significantly increase ATO's OEP and improve its electrochemical oxidation capacity through optimization of ATO's physical properties. These interlayers, however, are not suitable for application in TPTMs as Cu-NRs are inherently electrochemically instable, while the original zero-dimensional structure of TiN-NPs and that of the one-dimensional, stake-shaped TiO 2 -NTs are prone to being destroyed, blocked, or buried post catalyst coating, leading to unexpected loss of the electrode's electrochemically active area and porosity, both of which are vital for EF performance.…”