Enhanced electrochemical oxidation of phenol using a hydrophobic TiO₂-NTs/SnO₂-Sb-PTFE electrode prepared by pulse electrodeposition

Abstract

In this study, novel Sb-doped SnO 2 electrodes with a polyetrafluoroethylene (PTFE) composite were fabricated by pulse electrodeposition. In this process, vertically aligned TiO 2 nanotubes (TiO 2 -NTs) formed by anodization of Ti plates served as the substrate for SnO 2 eletrodeposition. Comparing with the conventional SnO 2 -Sb electrodes, TiO 2 -NTs/SnO 2 -Sb-PTFE electrodes have higher oxygen evolution potential, improved surface hydrophobicity, superior hydroxyl radical (HOc) generation and enhanced electrocatalytic activity by incorporation of PTFE nanoparticles. Field emission scanning electron microscopy (FESEM) shows that the surfaces of the PTFE composite electrodes exhibit a microspherical structure. Energy-dispersive X-ray spectroscopy (EDS) confirms the uniform distribution of Sn, Sb, F and C on TiO 2 -NTs/SnO 2 -Sb-PTFE surfaces. More importantly, the electrodes exhibit a distinctive improvement of oxygen evolution potential (OEP) from 2.0 to 2.4 V (vs. Ag/AgCl). The electrochemical impedance of TiO 2 -NTs/SnO 2 -Sb-PTFE also decreases significantly compared with Ti/SnO 2 -Sb(conventional). The electrocatalytic performance of TiO 2 -NTs/SnO 2 -Sb-PTFE compared with Ti/SnO 2 -Sb(conventional) and TiO 2 -NTs/SnO 2 -Sb were investigated using phenol as the model pollutant. The effects of initial solution pH and types of supporting electrolyte were investigated. The removal efficiency of total organic carbon (TOC), specific UV absorbance at 254 nm (SUVA 254 ), mineralization current efficiency (MCE) and energy consumption (E c ) with respect to different PTFE loadings on the electrodes were investigated. The anodic leaching of Sn ions was also studied under different conditions.

Electrochemical CO2 Reduction Using Electrons Generated from Photoelectrocatalytic Phenol Oxidation

“…[8] It has been shown that the consumed electric energy in these photoelectrocatalytic systems can be reduced due to the additional introduction of solar energy; the existence of synergistic effect between photocatalysts and electrocatalysts can lead to complete and rapid oxidation of pollutants to CO 2 and H 2 O. [9] Herein, an integrated cell is constructed to investigate simultaneously ECCO 2 R on a cathode and photoelectrocatalytic phenol oxidation reaction (PECPOR) on an anode. This is fully different from those reported where only individual ECCO 2 R or PECPOR is studied.…”

“…Energy Mater. 2019, 9,1900364 leads to a reduction of the current density. When the electrolysis time is longer than 2 h, the current density remains stable.…”

“…Energy Mater. 2019, 9,1900364 increased or the reaction time is prolonged ( Figure S5, Supporting Information). The replacement of Na 2 SO 4 with NaHCO 3 increases the amount of produced CO ( Figure S6, Supporting Information).…”

“…Energy Mater. 2019, 9,1900364 oxidation in the absence of phenol was conducted on the anode of Sb/SnO 2 -TiO 2 NTs under the identified conditions. After an electrolysis time of 6 h and CO 2 bubbling through the electrolyte of the cathode chamber, the phenol degradation ratio is above 60% at the current density of 10 or 20 mA cm −2 ( Figure S9, Supporting Information).…”

“…Energy Mater. 2019, 9,1900364 The recorded i-E features appear from −1.5 to −4 V at the cathode of copper nanowires ( Figure 6A-C), and +1.5 to +4 V at the BDD anode ( Figure 6D-F). At the oxidation voltage higher than +2.75 V ( Figure 6D) water oxidation to O 2 (namely, OER) occurs.…”