Influence of Gd Doping on the Structure and Electrocatalytic Performance of TiO₂ Nanotube/SnO₂−Sb Nano‐coated Electrode

Abstract

Gd‐doped TiO2−NT/SnO2−Sb (NT=nanotube) electrodes were prepared by using a solvothermal synthesis approach with a nano‐sized catalyst coating. Phenol degradation and total organic carbon (TOC) removal followed pseudo‐first‐order kinetics in the experimental range. A maximum rate was achieved by using a Gd doping ratio of 2 % (molar ratio based on Gd/Sn), which was 56.5 % and 68 % higher than that of the control (Gd/0 %) for phenol degradation and TOC removal. The results from the UV scan of the electrolyte showed that introducing an appropriate amount of Gd could promote the electrochemical incineration process, and thus effectively degrade the chemical intermediates during phenol oxidation. In addition, the Gd/2 %‐doped electrode had the longest accelerated life time of 25 h, which was 25 % higher than that of the control. A suitable Gd doping ratio could diminish the SnO2 crystal size and increase the specific surface area, speeding up the electrode's reaction rate, thus promoting the oxygen evolution potential. A regular and compact morphology with a smallest particle size of 9.5 nm was obtained on the Gd/2 %‐doped electrode, which prompted a smaller charge‐transfer resistance and higher electrical double‐layer capacitance than that of the control. The results from X‐ray photoelectron spectroscopy and electron paramagnetic resonance suggested that a maximal of surface active sites (i. e. oxygen vacancy) was formed on the Gd/2 %‐doped electrode, which provided abundant positive charge for adsorbing more oxygen species (37.5 %) than the control (21.5 %), and greatly enhanced the formation of ·OH to attack the targeted pollutant.

Gd‐Ni‐Sb‐SnO2 electrocatalysts for active and selective ozone production

“…Previous work on the EOP mechanism has suggested that Ni affects the mobility of lattice O, as reflected by crystallite size 16 . Other studies on doped SnO 2 have also observed that Ni and Gd doping modifies the bulk material unit cell parameters 20,53 . Figure 2 shows that the XRD peak positions of all samples are within experimental uncertainty.…”

“…16 Other studies on doped SnO 2 have also observed that Ni and Gd doping modifies the bulk material unit cell parameters. 20,53 Figure 2 shows that the XRD peak positions of all samples are within experimental uncertainty. The Scherrer length D was also calculated from the full-width-half-max peaks in the XRD.…”

“…18,19 Furthermore, a variety of transition metals and lanthanides have been probed as potential dopants in Sb-SnO 2 for phenol degradation. [20][21][22] Based on the similarity of applications, we hypothesized that active dopants for phenol oxidation would also yield active EOP catalysts. Our results show that Gd is indeed an active EOP dopant.…”

“…Because of its stability under oxidizing conditions and low activity for oxygen evolution, SnO 2 and Sb‐SnO 2 are frequently employed for electrolytic decomposition of organic pollutants 18,19 . Furthermore, a variety of transition metals and lanthanides have been probed as potential dopants in Sb‐SnO 2 for phenol degradation 20–22 . Based on the similarity of applications, we hypothesized that active dopants for phenol oxidation would also yield active EOP catalysts.…”

Improvement of the Electrochemical Behavior of (Sb, Sn, Cu)O Ceramic Electrodes as Electrochemical Advanced Oxidation Anodes

“…Among them, advanced oxidation processes (AOPs) have emerged as interesting alternatives. [4] The efficiency of these processes for removing recalcitrant pollutants from wastewaters has been widely reported in literature for a vast variety of recalcitrant pollutants: [5] pharmaceuticals, such as Propranolol and Diatrizoate; [6][7][8] dies, like Disperse Blue 3; [9,10] pesticides and herbicides, such as tebuthiuron and glyphosate; [11,12] and industrial compounds, like phenol, bisphenol A and EDTA. [13][14][15][16] Electrochemical advanced oxidation processes (EAOPs) are a particular type of AOPs that have gained increasing attention.…”