ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2023
·Vol. 30
·期 19
·56188-56197
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IF 5.8
Chen Jingwen,Wu Menglin,Ni Jiupai,Ni Chengsheng
Photocatalysis using the visible light of the sun is an environmentally friendly method of eliminating the NOx pollutant from the ambient air. Although Cs 3 Bi 2 Br 9 , a semiconductor with a band gap of 2.54 eV, may be a strong absorber of visible light, its photocatalysis towards the abatement of NOx is unknown. In this study, Cs 3 Bi 2-x Pb x Br 9-x (0 ≤ x ≤ 0.0789) are used for the photocatalytic oxidation of NOx. A significant NO oxidation efficiency (80%) is observed over Cs 3 Bi 2-x Pb x Br 9-x (x = 0.0443) under visible light, which is attributable to the Br vacancy ( V Br ) brought about by Pb 2+ doping. The presence of V Br increased the ionic selectivity of in the oxidized NO. At higher Pb doping level, two HONOs adsorbed on the V Br , linked, and then reduced by hot electrons to produce N 2 O 2 2− . The di-azo coupling could passivate the activation of NO on the V Br . This work advances the defect engineering of halide for the photo-driving solid–gas reaction in air.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2020
·
IF 2.213
Haiqian Zhao,Ming Dong,Zhonghua Wang,Huaiyuan Wang,Hanbing Qi
Low H2O2 utilization efficiency is the main problem when Fenton system was used to oxidize NO in flue gas. To understand the behaviour of the free radicals during NO oxidation process in Fenton system is crucial to solving this problem. The oxidation capacity of ⋅OH and HO2⋅ on NO in Fenton system was compared and the useless consumption path of ⋅OH and HO2⋅ that caused the low utilization efficiency of H2O2 were studied. A method to enhance the oxidation ability and H2O2 utilization efficiency by adding reducing additives in Fenton system was proposed. The results showed that both of ⋅OH and HO2⋅ were active substances that oxidize NO. However, the oxidation ability of ⋅OH radicals was stronger. The vast majority of ⋅OH and HO2⋅ was consumed by rapid reaction ⋅OH + HO2⋅→H2O + O2 , which was the primary reason for the low utilization efficiency of H2O2 in Fenton system. Hydroxylamine hydrochloride and ascorbic acid could accelerate the conversion of Fe3+ to Fe2+, thereby increase the generation rate of ·OH and decrease the generation rate of HO2⋅. As a result, the oxidation ability and H2O2 utilization efficiency were enhanced.
研究领域:
环境科学
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化学
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DOI
PubMed
高影响因子
PLoS One
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2018
·Vol. 13
·期 4
·e0192324
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IF 2.766
Hai-qian Zhao,Zhong-hua Wang,Xing-cun Gao,Cheng-hao Liu,Han-bing Qi
H 2 O 2 was adopted to oxidize NO in simulated flue gas at 100–500°C. The effects of the H 2 O 2 evaporation conditions, gas temperature, initial NO concentration, H 2 O 2 concentration, and H 2 O 2 :NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NO x using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H 2 O 2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300–500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H 2 O 2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H 2 O 2 . The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H 2 O 2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H 2 O 2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H 2 O 2 :NO molar ratio, but the ratio of H 2 O 2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO 2 , which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.
研究领域:
环境科学
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化学工程
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PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Tong Zhang,Hui Li,Zhi Yang,Fengren Cao,Liang Li,Haijun Chen,Hui Liu,Ka Xiong,Jie Wu,Zhanglian Hong,Weichao Wang
Nanofiber catalysts are potentially promising to be equipped in the lean-burned vehicle exhaust emission system considering its facile synthesis, low-cost, long durability in contrast to the traditionally complicated powder based catalyst. Here, via electrospinning method, we synthesized YMn 2 O 5 nanofibers (average diameter: ˜93 nm) including nanowire stacked with particles, and hollow tubes with or without inside nanowires. The morphologies remained even after hydrothermal aging at 800 ℃ for 10 h with 10% H 2 O stream. X-ray photoelectron spectrum revealed Mn 4+ /Mn 3+ ratio 0.589 on the surface of YMn 2 O 5 catalyst (YMO), indicating the existence of oxygen vacancies. The highest conversion of electrospun mullite fibers at 310 ℃ is ˜18% higher than powder-based YMO at 352 ℃ in the presence of 5% H 2 O at WHSV = 240,000 ml g −1 h −1 . The extracted activation energy from NO-to-NO 2 conversion curves of YMO nanofiber (61.68 kJ/mol) is slightly lower than that of powder-based mullite (91.45 kJ/mol), consistent with calculated 68.16 kJ/mol on the fiber YMO surface (121) with a rate-limiting step of the NO 2 desorption. The catalytic activity can be attributed to the unit occupy of the e g ( d z 2 and d x 2 -y 2 ) orbitals of Mn-dimer atoms around fermi level based on the combination of the theoretical calculations and DRIFTS spectra analysis. Importantly, after the hash hydrothermal-aging, the highest NO oxidation conversion of powder-based mullite is less than 50%, while the fiber maintains a conversion of 62%. Moreover, the fresh YMO fiber maintained superior oxidation stability for 12 h at its maximum conversion of 66%. This work provides the possibility for mullite oxide fibers to replace powder-based precious metal catalyst coating on monolith converter.
研究领域:
材料科学
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环境科学
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Shujun Sun,Jun Zhang,Changdong Sheng,Hui Zhong
NO in flue gas is one of the atmospheric pollutants, and it is necessary to study effective NO removal technology. It was identified that the alkaline H 2 O 2 system achieved over 98 % NO removal efficiency with a gas–liquid contact time of 3 s in this paper. This paper investigates the mechanism of NO removal in alkaline H 2 O 2 solution through both experimental and theoretical calculations. The results reveal the NO removal process can be divided into three phases by the NaOH/H 2 O 2 molar ratio. (1) The ∙O 2 – dominated phase, where trace metal Fe catalyzes ∙O 2 – radical generation from H 2 O 2 as Fe (OH) 2+ , reacting primarily with NO to form ONOO – . The energy barrier for this process is1.299 kcal/mol, with a reaction rate constant of 9.12 E + 11 s -1 M −1 . (2) The HO 2 – dominated phase, HO 2 – was generated through OH – and H 2 O 2 neutralization, which converts NO to NO 2 and regenerating OH – . The energy barrier for HO 2 – reacting with NO is 3.833 kcal/mol, and the reaction rate constant is 2.07E + 10 s -1 M −1 . (3) The O 2 2– dominated phase, O 2 2– was a further ionization of HO 2 – and converting NO to NO 2 – directly. The energy barrier for this process is 7.079 kcal/mol, and the reaction rate constant is 1.49 E + 08 s -1 M −1 .
研究领域:
环境科学
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化学工程
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
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IF 14.224
Fengyi Zhong,Chaowei Yuan,Ye He,Yanjuan Sun,Jianping Sheng,Fan Dong
Constructing heterostructure is an effective way to fabricate advanced photocatalysts. However, the catalytic performance of typical common multi-dimensional bulk heterostructure still suffers from the limited active interface and inefficient carrier migration. Herein, we successfully synthesize the SnO 2 /Cs 3 Bi 2 I 9 dual-quantum-dots nanoheterostructure (labeled as SCX, X = 1, 2, 3) for efficiently and stably photocatalytic NO removal under visible light irradiation. The NO removal rate of SC2 is almost 8 and 17 times higher than that of the single SnO 2 and Cs 3 Bi 2 I 9 , respectively. Moreover, the SC2 photocatalyst shows only 3 % attenuation after five consecutive cycles, demonstrating good photocatalytic stability. Systematic experimental characterization and theoretical density functional theory calculations revealed that the high activity and stability of SCX originated from the efficient charge transfer at the confined interface between SnO 2 and Cs 3 Bi 2 I 9 quantum dots . This work provides a new perspective for constructing innovative dual-quantum-dots nanoheterostructure and assesses their potential in photocatalytic environmental applications.
研究领域:
材料科学
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环境科学
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理论计算
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高影响因子
Environmental Progress & Sustainable Energy
·
2012
·Vol. 32
·期 3
·564-568
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IF 1.649
Wei-guo Pan,Rui-tang Guo,Xiao-bo Zhang,Jian-xing Ren,Qiang Jin,Hong-jian Xu
The absorption process of NO into KMnO 4 /(NH 4 ) 2 CO 3 solutions was studied in a stirred tank reactor. The experimental results showed that the reaction process was a fast pseudo-m reaction. The reaction between NO and aqueous solutions of KMnO 4 /(NH 4 ) 2 CO 3 was found to be first-order with respect to NO and with respect to KMnO 4 . The frequency factor and the average activation energy of this reaction were 2.3 × 10 9 m 3 /(mol s) and 36.77 kJ/mol, respectively. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 564–568, 2013
研究领域:
环境科学
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化学工程
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高影响因子
FUEL
·
2022
·
IF 8.035
Jiaxiu Guo,Ting Shen,Juan Liang,Shulin He,Yue Jing,Yinghao Chu,Wanglai Cen
In this paper, an N -doped BiOCl photocatalyst was prepared and systematically characterized. The results showed that N doping does not change the crystal phase of BiOCl but changes the surface morphology of BiOCl nanosheets and increases specific surface area. N -doped BiOCl broadens the light absorption region, narrows the band gap and promotes the separation of the photoexcited carriers. N could be adsorbed on the Bi or to replace Cl atom in the BiOCl lattice, causing the generation of intermediate energy levels in the band gap of N -BiOCl including N 2p-Cl 2p hybrid states, N 2p-O 2p hybrid states or N 2p state. N -BiOCl achieves about 60% removal efficiency of NO under all-light irradiation and exhibits favorable stability and recyclability. The presence of some H 2 O in the reaction system promotes the photodegradation of NO, while O 2 greatly affects the efficiency of NO removal. Moreover, N doping promotes the formation of •O 2 − and •OH on N -BiOCl photocatalyst under all-light irradiation, resulting in the enhancement of photocatalytic oxidation of NO to NO 3 – . NO could be adsorbed on the surface of N -BiOCl or oxidized into NO 2 – under darkness and further oxidized into NO 3 – under all-light irradiation. However, the accumulation of the final product on the catalyst surface results in a decrease in photoactivity.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Cheng Cheng,Dongyun Chen,Najun Li,Hua Li,Qingfeng Xu,Jinhui He,Jianmei Lu
Semiconductor materials have been used for photocatalytic degradation since they were discovered to be useful for photocatalytic degradation. Many studies have been researched to improve the efficiency of photocatalytic degradation. Among them, the introduction of vacancies to improve the photocatalytic efficiency has been verified to be a more feasible method. In this study, we combined two-dimensional (2D) graphite carbon nitride (g-C 3 N 4 ) nanosheets with oxygen-containing vacancy zero-dimensional (0D) Bi 2 WO 6 (BWO-OV) quantum dots to prepare 2D-0D g-C 3 N 4 /Bi 2 WO 6 -OV composite catalyst. The use of Bi 2 WO 6 containing oxygen vacancies enhanced the absorption of light and increased the generation of photogenerated carriers. In addition, the formation of heterojunction and the vacancy structure of Bi 2 WO 6 promote the life of photogenerated carriers and improve the catalytic effect of the catalyst. This structure shows high efficiency in removing low concentration (0.5 ppm) of nitric oxide (NO) at room temperature. The efficiency of the composite catalyst is much higher than g-C 3 N 4 or BWO-OV, and better than the composite g-C 3 N 4 /Bi 2 WO 6 without oxygen vacancies. When applied to NO removal, the composite g-C 3 N 4 /Bi 2 WO 6 -OV-10 showed the best catalytic activity which was up to 61.2%. At the same time, five cycles of experiments show that the material has excellent stability.
研究领域:
材料科学
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环境科学
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PubMed
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Longcheng Zhang,Qiang Zhou,Jie Liang,Luchao Yue,Tingshuai Li,Yongsong Luo,Qian Liu,Na Li,Bo Tang,Feng Gong,Xiaodong Guo,Xuping Sun
Electrochemical reduction of NO to NH3 is of great significance for mitigating the accumulation of nitrogen oxides and producing valuable NH3. Here, we demonstrate that the CoS nanosheet with sulfur vacancies (CoS1–x) behaves as an efficient catalyst toward electrochemical NO-to-NH3 conversion. In 0.2 M Na2SO4 electrolyte, such CoS1–x displays a large NH3 yield rate (44.67 μmol cm–2 h–1) and a high Faradaic efficiency (53.62%) at −0.4 V versus the reversible hydrogen electrode, outperforming the CoS counterpart (27.02 μmol cm–2 h–1; 36.68%). Moreover, the Zn–NO battery with CoS1–x shows excellent performance with a power density of 2.06 mW cm–2 and a large NH3 yield rate of 1492.41 μg h–1 mgcat.–1. Density functional theory was performed to obtain mechanistic insights into the NO reduction over CoS1–x.
研究领域:
材料科学
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电化学
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环境科学
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PubMed
高影响因子
Processes
·
2022
·Vol. 11
·期 1
·115
·
IF 3.352
Ting Gao,Jingqi Lin,Ke Zhang,Mohsen Padervand,Yifan Zhang,Wei Zhang,Menglin Shi,Chuanyi Wang
Since conventional techniques are ineffective for NO removal at low concentrations, photocatalysis has become attractive in this regard, recently. However, in practice, photocatalytic NO removal has drawbacks such as limited light absorption and the proclivity of producing toxic by-products. To address these issues, novel defective Bi/Bi3NbO7structures with good porosity were fabricated by a solvothermal method and used for enhanced photocatalytic NO removal under visible light irradiation. The morphological and structural properties of the prepared materials were comprehensively analyzed. The optimal photocatalytic activity of pore-defective Bi/Bi3NbO7for NO removal was 60.3%, when the molar ratios of urea and Bi(NO)3•5H2O to pristine Bi3NbO7were 1:25 and 1:2, respectively, under the following operational conditions: NO concentration of 700 ppb, catalyst dosage of 50 mg and irradiation time of 14 min. The induced defects and the surface plasmon resonance (SPR) effect of Bi nanodots made remarkable contributions to improving the photocatalytic NO removal as well as inhibiting the toxic byproduct NO2. The photocatalytic NO removal pathway over the prepared photocatalysts was further mechanistically clarified taking advantage of EPR results and scavenging experiments. Considering the increased NO generation in the atmosphere, this work may provide novel insights for designing effective porous photocatalysts to treat gaseous toxic pollutants.Keywords:photocatalysis;Bi3NbO7;surface plasmon resonance;NO removal;defects
研究领域:
环境科学
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材料科学
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2017
·
IF 3.752
Tiantian Cao,Zijian Zhou,Qian Chen,Zhen Li,Shengming Xu,Jianlong Wang,Minghou Xu,Teresa Bisson,Zhenghe Xu
A novel class of magnetically responsive catalytic sorbents are proposed and synthesized with a potential application to simultaneous removal of Hg 0 and NO at low temperature from the flue gases of coal-fired power plants. The catalytic sorbent consists of magnetite (Fe 3 O 4 ), molecular sieve (HZSM-5), supported silver nanoparticles and catalytically reactive component of V 2 O 5 . Each of these materials provides a unique function for the purpose of capturing mercury, removing NO, and separation from fly ash. After separation from the fly ash, the spent sorbent can be regenerated and reused, leaving an uncontaminated fly ash product. The successful synthesis as designed was confirmed and properties of the catalytic sorbent were characterized by several methods. The synthesized catalytic sorbent was able to completely capture Hg 0 at 150 °C with a capture capacity as high as 32.4 μg·g −1 , while achieving 84% removal of NO at 150 °C. Even at a relatively high space velocity, the catalytic sorbent achieved 97% Hg 0 and 80% NO removal simultaneously, while maintaining a good stability after repetitive regeneration and recycle. The magnetically responsive catalytic composite was shown to be a promising candidate for multi-pollutant emission control from coal-fired power plants.
研究领域:
环境科学
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材料科学
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高影响因子
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