Engineering
·
2023
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IF 12.8
Xiaoyu Li,Xiaoshu Lv,Jian Pan,Peng Chen,Huihui Peng,Yan Jiang,Haifeng Gong,Guangming Jiang,Li'an Hou
Photocatalysis offers a sustainable avenue for the oxidative removal of low concentrations of NO x from the atmosphere. Layered double hydroxides (LDHs) are promising candidate photocatalysts owing to their unique layered and tunable chemical structures, and the abundant hydroxide (OH − ) moieties on their surfaces that are hydroxyl radical ( • OH) precursors. However, inferior charge separation and limited active sites on an LDH hinder its practical applications. Herein, we developed a facile N 2 H 4 -driven etching (et) approach that introduces dual Ni 2+ and OH − vacancies (Ni v and OH v ) into NiFe-LDH nanosheets (referred to as NiFe-LDH-et) that facilitate improved charge-carrier separation and the formation of active Lewis acidic sites (Fe 3+ and Ni 2+ exposed at OH v ). In contrast to inert pristine LDH, NiFe-LDH-et actively removes NO when illuminated with visible light. Specifically, Ni 76 Fe 24 -LDH - et etched in 1.50 mmol·L −1 N 2 H 4 solution removes 32.8% of the NO from continuously flowing air (NO-feed concentration: ∼500 parts per billion (ppb)) when illuminated with visible light, thereby outperforming most reported catalysts. Experimental and theoretical data reveal that the dual vacancies promote the production of reactive oxygen species ( • O 2 − and • OH) and the adsorption of NO on the LDH. In-situ spectroscopy revealed that NO is preferentially adsorbed at Lewis acidic sites, particularly exposed Fe 3+ sites, and then converted into NO + that is subsequently oxidized to NO 3 − without the formation of any of the more toxic NO 2 intermediate, thereby alleviating risks associated with its production and emission.
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Communications Chemistry
·
2023
·Vol. 6
·期 1
·1-10
·
IF 5.9
Li Pan,Gemayel Rachel,Li Xue,Liu Jiangping,Tang Mingjin,Wang Xinming,Yang Yan,Al-Abadleh Hind A.,Gligorovski Sasho
Heterogeneous reaction of gas phase NO 2 with atmospheric humic-like substances (HULIS) is potentially an important source of volatile organic compounds (VOCs) including nitrogen (N)-containing compounds, a class of brown carbon of emerging importance. However, the role of ubiquitous water-soluble aerosol components in this multiphase chemistry, namely nitrate and iron ions, remains largely unexplored. Here, we used secondary electrospray ionization ultrahigh-resolution mass spectrometry for real-time measurements of VOCs formed during the heterogeneous reaction of gas phase NO 2 with a solution containing gallic acid (GA) as a proxy of HULIS at pH 5 relevant for moderately acidic aerosol particles. Results showed that the number of detected N-containing organic compounds largely increased from 4 during the NO 2 reaction with GA in the absence of nitrate and iron ions to 55 in the presence of nitrate and iron ions. The N-containing compounds have reduced nitrogen functional groups, namely amines, imines and imides. These results suggest that the number of N-containing compounds is significantly higher in deliquescent aerosol particles due to the influence of relatively higher ionic strength from nitrate ions and complexation/redox reactivity of iron cations compared to that in the dilute aqueous phase representative of cloud, fog, and rain water.
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PubMed
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Wenlei Zhang,Weiheng Wang,Yunfan Wang,Lei Sun,Yongjiao Sun,Jie Hu
The continuous discharging of nitrogen dioxide (NO 2 ) significantly damaged global environment and human health. In this study, SnS 2 microflowers/Ti 3 C 2 MXene heterostructure was modified by Au nanoparticles (AuNPs) for the detection of NO 2 at room temperature. The microcomposite decorated with 6 wt% AuNPs exhibited excellent sensing properties including response value of 5.34 to 1 ppm NO 2 , which was almost 5 times higher than that of undecorated one. The limit of detection lowered from 500 ppb to 5 ppb with the addition of AuNPs. Besides, the AuNPs decorated SnS 2 /MXene microcomposite revealed good selectivity, fatigue resistance, as well as potential application towards flexible sensing. The NO 2 gas sensing mechanism of AuNPs decorated with SnS 2 /Ti 3 C 2 MXene microcomposite was discussed through density functional theory calculation on adsorption behavior and transferred charges in detail. This work may provide an important pathway for the future development of NO 2 sensors at room temperature.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Li Liu,Yang Gao,Qinghua Hu
Constructing heterogeneous interfaces on a nanoscale that can prominently improve the gas-sensing properties has been comprehensively reported. However, the effect of parallel heterostructures formed by unique synthetic means on nitrogen dioxide room-temperature sensing properties still needs to be clarified, which hinders the development of heterostructured hybrid materials in the field of gas sensing. In this study, large-sized MoS2 was parallel-wrapped on the surface of nanoscale Bi2S3 rods, and then, the Bi2S3/MoS2 nanocomposite aerogels were formed by freeze drying and calcination. The NO2 sensing performance of the hybrids and possible surface processes at room temperature have been investigated and deduced. The as-prepared nanocomposite aerogels (Bi2S3/MoS2-2) exhibited a larger specific surface area, a mass of active defect sites, and a higher charge density, thus possessing 15- and 20-times higher response than that of pristine MoS2 nanosheets and Bi2S3 nanorods, respectively. This study provides an efficient way to synthesize large-area parallel heterostructures between two bis-sulfides (Bi2S3 and MoS2), leading to excellent NO2 gas sensing performance.
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FUEL
·
2019
·
IF 5.128
Xiao Zhu,Liqiang Zhang,Mengze Zhang,Chunyuan Ma
Due to high adsorption capacity, NO 2 adsorption using activated carbon has become a potential denitration technology. A correlation between N-doping and NO 2 adsorption process on activated carbon is pointed out by previous studies but lacks a clear explanation. The main objective of this work is to clarify the influencing mechanism of N-doping on NO 2 adsorption and reduction over activated carbon. N-doped activated carbons were synthesized by melamine impregnation followed by calcination and tested as NO 2 adsorbents. Experimental results showed that AC600 with highest N content possessed highest NO 2 adsorption capacity and lowest NO release percentage. NO 2 adsorption on activated carbon is a complex process, including NO 2 adsorption, NO 2 reduction to NO, and NO release. Density functional theory calculations results showed that N-doping affected all steps mentioned above. Firstly, N-doping increased NO 2 physisorption energies, meaning that NO 2 was easier to be adsorbed. Thus, NO 2 adsorption capacities increased with the increase of N content experimentally. Secondly, N-doping increased the energy barrier of the rate-determining step of NO 2 reduction. Thus, the reduction of NO 2 to NO was harder. Thirdly, N-doping increased NO desorption energies, implying that the release of generated NO was harder. The inhibition of NO 2 reduction and NO desorption results in the decrease of NO release percentage due to N-doping jointly. This work elucidates the influencing mechanism of N-doping on NO 2 adsorption and NO 2 reduction on theoretical level, which fills up the research gap and guides the design of activated carbon for efficient NO 2 adsorption.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Yunshi Liu,Xiupeng Liu,Yubing Wang,Rui Wang,Tong Zhang
A novel synthesis of In 2 O 3 porous microcolumnar structures (MCs) by a self-sacrificial template route was carried out using MIL-68. Using a modified calcination strategy, the samples could maintain the original metal organic frame work (MOF) morphology with a high gas accessibility after a slow decomposition of organic ligands. Pt nanoparticles (NPs) were loaded on the samples before or after the MOF calcination, leading to different contact states of the Pt NPs and In 2 O 3 matrix. The gas sensing properties of the samples were systematically investigated using a dynamic testing system. Particularly, sample Pt/In 2 O 3 MCs-1 exhibited a superior NO 2 sensing performance near room temperature ( R g / R a = 44.9 at 1 part-per-million and 5.2 at 100 parts-per-billion (ppb)). The sensor resistance could recover to its baseline even at 40 °C after purging with air without any additional treatment. This can be attributed to the chemical sensitisation of the Pt NPs as well as large contents of pores and channels for gas diffusion. The introduction of humidity in the gas mixture could remarkably decrease the sensor response and recovery times owing to the ‘wet’ NO 2 adsorption mechanism. This study demonstrated a novel synthesis route of Pt-loaded In 2 O 3 porous columnar structures and its potential applications in near-room-temperature detection of ppb-level NO 2 .
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CHINESE JOURNAL OF CATALYSIS
·
2018
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IF 3.525
Lei Chen,Ding Weng,Jiadao Wang,Duan Weng,Li Cao
The CeO 2 -TiO 2 (CeTi) and CeO 2 /WO 3 -TiO 2 (CeWTi) catalysts were prepared by a sol-gel precipitation method and their NH 3 -NO/NO 2 selective catalytic reduction (SCR) performance was studied. N 2 O formation and effect of oxygen concentration on SCR performance over CeWTi catalyst were also investigated while varying the NO 2 /NO x ratio. Results indicate that fast SCR behavior of CeWTi catalyst has the best NH 3 -NO/NO 2 SCR performance due to the catalyst reoxidation rate by NO 2 higher than by O 2 . Compared with CeTi catalyst, CeWTi catalyst exhibits higher de-NO x performance under NH 3 -NO/NO 2 SCR conditions. As the CeTi and CeWTi catalysts exhibit similar redox property, addition of WO 3 provides more acid sites which accelerate the reaction between NH 4 NO 3 and NO to get a superior low-temperature activity. Amount of N 2 O formation shows a peak at 250 °C mainly derived from NH 4 NO 3 decomposition.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Tianyi Han,Shang Gao,Ziying Wang,Teng Fei,Sen Liu,Tong Zhang
A series of reduced graphene oxide (rGO) samples were prepared by hydrothermal reduction of graphene oxide (GO) samples, which were obtained by a modified Hummers’ method at oxidation temperatures of 65 °C, 75 °C, 85 °C, and 95 °C. The combined characterizations indicate that the number of C–O bonds in rGO samples increases with an increasing oxidation temperature of GO from 65 °C to 85 °C and then decreases when the temperature is further increased to 95 °C. Most importantly, the rGO obtained from the GO at an oxidation temperature of 85 °C (designated as rGO-85) exhibits a higher response to 5 ppm NO 2 (36.7%) at room temperature than the other three rGO samples, which is attributed to the high content of C–O bonds in the rGO-85 sample. This work suggests that the gas sensing properties of rGO-based sensors can be tuned by changing the number of oxygen-containing groups in rGO.
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ACS Sensors
·
2024
·
IF 8.2
Chao Fan,Jianhua Yang,Jaafar Abdul-Aziz Mehrez,Yongwei Zhang,Wenjing Quan,Jian Wu,Xue Liu,Min Zeng,Nantao Hu,Tao Wang,Bing Tian,Xiaopeng Fan,Zhi Yang
Rapid and ultrasensitive detection of toxic gases at room temperature is highly desired in health protection but presents grand challenges in the sensing materials reported so far. Here, we present a gas sensor based on novel zero dimensional (0D)/two dimensional (2D) indium oxide (In2O3)/titanium carbide (Ti3C2Tx) Schottky heterostructures with a high surface area and rich oxygen vacancies for parts per billion (ppb) level nitrogen dioxide (NO2) detection at room temperature. The In2O3/Ti3C2Tx gas sensor exhibits a fast response time (4 s), good response (193.45% to 250 ppb NO2), high selectivity, and excellent cycling stability. The rich surface oxygen vacancies play the role of active sites for the adsorption of NO2 molecules, and the Schottky junctions effectively adjust the charge-transfer behavior through the conduction tunnel in the sensing material. Furthermore, In2O3 nanoparticles almost fully cover the Ti3C2Tx nanosheets which can avoid the oxidation of Ti3C2Tx, thus contributing to the good cycling stability of the sensing materials. This work sheds light on the sensing mechanism of heterojunction nanostructures and provides an efficient pathway to construct high-performance gas sensors through the rational design of active sites.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Shihang Yan,Zhengrun Chen,Ya Wang,Jieqiang Wang,Hongyan Xu
For NO 2 , a gas that is widely used and harmful, domestic and foreign researchers have done a lot of work to develop a sensor with low detection limit and low humidity sensitivity to achieve efficient detection of NO 2 . In this work, first of all, dense and uniform SnO 2 nanosheets were grown in situ on the surface of Al 2 O 3 ceramic tube by hydrothermal method. Then, the ZIF-8@SnO 2 porous composite gas-sensitive material was constructed by solvent thermal method. With the advantages of the ZIF-8 porous screening framework, the permeation of different gases can be selectively controlled, and the adsorption efficiency of NO 2 gas can be enhanced through the modification of ammonia to improve the selectivity of NO 2 . The results show that the response of the Modified-ZIF-8@SnO 2 sensor is significantly enhanced, and the selectivity is greatly improved at low operating temperature. At 140 °C, the response of Modified-ZIF-8@SnO 2 to 50 ppm NO 2 gas is as high as 61, which is about 18.4 times higher than that of SnO 2 nanosheets and about 16.3 times higher than that of ZIF-8@SnO 2 . Meanwhile, the anti-interference ability of the Modified-ZIF-8@SnO 2 sensor to humidity has been improved. This work provides a new idea for improving the selectivity and humidity insensitivity of gas sensors.
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Gen Li,Jinan Li,Ya Wang,Yuhang Du,Hongyan Xu,Yan Wang
In this research, a two-step hydrothermal method was used to fabricate a NO 2 sensor based on WO 3 @ZIF-8 core-shell nanorods grown on ceramic tubes. The material's morphology, nanostructure, and composition were thoroughly characterized. The nanocomposites consisting of WO 3 @ZIF-8 showed significant sensing response (65) toward 50 ppm NO 2 at 200 °C. The WO 3 @ZIF-8 core-shell nanomaterials demonstrated exceptional selectivity to NO 2 against TEA and possessed good repeatability. Moreover, the distinctive core-shell nanorods structure promote the process of transferring the electrical charge of the carrier and the response to the targeted gas. The outer coating of ZIF-8 microporous material, with small pore window size (0.5–0.7 nm), had a sieving effect on large molecular interference gases. Further, we combined density functional theory (DFT) calculations and molecular dynamics simulations to investigate the reaction mechanism of the sensors.
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ACS Applied Nano Materials
·
2025
·
IF 5.5
Zixu Wang,Linna Han,Qing Xia,Wanfang Feng,Songtao Li,Liyan Liu
Enrichment and quantification of sugar phosphates (SPx) in biological samples are of great significance in biological medicine. In this work, a magnetic nanoscale metal–organic framework composite, Fe3O4@UiO-66-NO2, was synthesized and utilized as a high-capacity adsorbent for the enrichment of SPx in biological samples. Fe3O4@UiO-66-NO2 exhibited a high specific surface area (310.02 m2/g), a suitable pore size (3.47 nm), and strong magnetism (14.99 emu/g), enabling convenient separation and recovery. Experimental results demonstrated that Fe3O4@UiO-66-NO2 exhibited excellent adsorption performance for five types of SPx, achieving complete adsorption within 6 min at a dosage of 200 μg, and the adsorption process exhibited pH tolerance. The adsorption isotherm result indicated that the maximum adsorption capacities for different SPx ranged from 234.06 mg/g to 403.24 mg/g. Adsorption mechanisms using X-ray photoelectron spectroscopy, FT-IR, and density functional theory revealed multiple interactions, such as coordination and hydrogen bonding, and contributed to the adsorption process. A magnetic nanoscale-dispersive solid-phase extraction protocol was developed based on a Fe3O4@UiO-66-NO2 for rapidly enriching SPx from biological samples. The protocol allowed for SPx detection over a wide linear concentration range, low limits of detection (0.001–0.02 ng/mL), high precision (<7.88%), and good accuracy (82.56%–119.66%). This protocol was successfully applied to real blood samples, prefiguring the great potential of magnetic MOFs for the enrichment and detection of SPx in biological samples.
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