Enhanced performance of alkali-modified Bi2WO6/Bi0.15Ti0.85O2 toward photocatalytic oxidation of HCHO under visible light

Photocatalytic oxidation of formaldehyde (HCHO) is considered as one of the promising ways to resolve indoor air HCHO pollution. TiO 2 has been well known as the most extended application in photocatalysis due to its strong oxidizing ability and stability. Owing to high activity under visible light...

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Bibliographic Details
Published in:Environmental science and pollution research international 2019-04, Vol.26 (10), p.9672-9685
Main Authors: Huang, Qiong, Ye, Juan, Si, Han, Ruan, Jiaxin, Xu, Mengxin, Yang, Bo, Tao, Tao, Zhao, Yunxia, Chen, Mindong
Format: Article
Language:English
Subjects:
Aquatic Pollution
Atmospheric Protection/Air Quality Control/Air Pollution
Bismuth compounds
Bismuth oxides
Bismuth trioxide
Carbon dioxide
Catalysis
Catalysts
Conversion
Earth and Environmental Science
Ecotoxicology
Environment
Environmental Chemistry
Environmental Health
Environmental science
Heterojunctions
Indoor air pollution
Indoor environments
Irradiation
Light irradiation
Oxidation
Performance enhancement
Photocatalysis
Photooxidation
Reaction mechanisms
Recombination
Research Article
Salts
Sodium sulfate
Titanium dioxide
Tungstates
Waste Water Technology
Water Management
Water Pollution Control
X ray photoelectron spectroscopy
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Summary:Photocatalytic oxidation of formaldehyde (HCHO) is considered as one of the promising ways to resolve indoor air HCHO pollution. TiO 2 has been well known as the most extended application in photocatalysis due to its strong oxidizing ability and stability. Owing to high activity under visible light irradiation, TiO 2 and Bi 2 O 3 doping mixed with Bi 2 WO 6 was analyzed in this study. The formation of two kinds of heterojunction caused efficient charge separation, leading to the effective reduction in the recombination of photo-generated electron and hole. The special structure and enhanced performance of these catalysts were analyzed. For the first time, the loading of alkali salts was researched for photocatalytic oxidation. In order to understand the reaction mechanism of alkali salts enhanced effects, the catalysts were investigated by using BET, XRD, UV–Vis, FT-IR, SEM, and XPS. The results found more than 2 wt% of Na 2 SO 4 loading and the mixed methods with different solutions were key factors affecting the performance of catalysts. Nearly 92% HCHO conversion could be completed over Bi 2 WO 6 /Bi 0.15 Ti 0.85 O 2 (Na 2 SO 4 ), and the concentration of HCHO was only 0.07 mg/m 3 for 24 h, which was below the limit of specification in China. The results also indicated that the solution mixing method was more favorable to increase the HCHO conversion due to decrease the size of Bi 0.15 T i0.85 O 2 particles. The catalysts with Na 2 SO 4 loading provided more surface-adsorbed oxygen that facilitated the desorption of CO 2 and markedly increased the photocatalytic oxidation of HCHO. Graphical abstract Plausible mechanism over W-Bi2WO6/ Bi0.15Ti0.85O2-Na2SO4 (1:4) catalysts
ISSN:0944-1344
1614-7499
DOI:10.1007/s11356-019-04277-0