Electrochemical preparation of Nb2O5 nanochannel photoelectrodes for enhanced photoelectrocatalytic performance in removal of RR120 dye

Author(s)

Khan, Saad Ullah ^{[1, 2, 3]} ; Lima Perini, Joao Angelo ^{[1, 3]} ; Hussain, Sajjad ^[2] ; Khan, Hammad ^[2] ; Khan, Sabir ^{[1, 3, 4]} ; Boldrin Zanoni, Maria V. ^{[1, 3]}

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, Araraquara, SP - Brazil

^[2] GIK Inst Engn Sci & Technol, Fac Mat & Chem Engn, Topi - Pakistan

^[3] Sao Paulo State Univ UNESP, Natl Inst Alternat Technol Detect Toxicol Evaluat, Inst Chem, Araraquara, SP - Brazil

^[4] Natl Univ Engn, Lab Phys Chem Res, Fac Sci, Lima - Peru

• Document type: Journal article
• Source: Chemosphere; v. 257, OCT 2020.
• Web of Science Citations: 0

Abstract

The present work describes the synthesis of niobium oxide nanochannels (Nb2O5NCs) with high surface area, porosity, photocurrent density, and photoelectrochemical stability as photocatalyst. The Nb2O5NCs were prepared by electrochemical anodization of niobium foil in different electrolytes: 1 M H2SO4 containing 0.4 wt% HF (S1); glycerol containing 0.4 M NH4F (S2); 0.25 g NH4F with 4 vol% water in glycol at 50 degrees C (S3); and glycerol containing 10 wt% K2HPO4 , at 130 degrees C (S4, annealed in air; S5, annealed in N-2). All the Nb2O5 NCs showed well-organized arrays of nanochannels grown on the Nb foil, with tube diameters in the order S1<S2<S3<S4< as determined using FEG-SEM analyses. The samples were also characterized using XRD, EDX, DRS, XPS, EIS, Mott-Schottky analysis, and LSV curves. But, best results were obtained only when phosphorus (about 1% doping) was incorporated into the electrodes samples prepared in glycerol containing 10 wt% K2HPO4 at 130 degrees C (i.e. S4 and S5). This procedure enhances the absorption intensity in the UV-Vis regions, the conductivity, the charge carrier density, and the photocurrent density. The Nb2O5NC sample S5 was tested for the degradation of Procion Red HE-3B (RR120) dye, as a model pollutant, achieving efficient photo-electrodegradation with nearly 2 times higher mineralization efficiency compared to photolysis (PT) and photocatalysis (PC). Thus, the results indicate that the modification of Nb2O5NC thin film photoelectrodes by phosphorous doping can be a powerful and efficient alternative to usual approaches applied to the treatment of complex reactive dyes. (C) 2020 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/18057-7 - CO2 reduction aiming to generate value-added compounds by photocatalysis/photoelectrocatalysis using ionic liquid in a pressurized reactor
• Grantee: João Angelo de Lima Perini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral