CATALYSIS LETTERS
·
2020
·Vol. 150
·期 7
·1890-1897
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IF 2.482
Zhou Na,Yan Ruiyao,Pan Yanlin,Fang Xue-Qian
The fast recombination of photogenerated electrons and holes in the pure TiO 2 leads to a low photocatalytic efficiency in hydrogen generation or solar energy conversion. Noble metal nanoparticles have been used to combine with TiO 2 for effective photocatalysis. Herein, Au@Ag@TiO 2 nanorods (NRs) with core–shell structure have been prepared by hydrolysis the precursor of titanium in acid environment. UV light–driven H 2 generation rate of Au@Ag@TiO 2 samples demonstrated 14 times enhancement compared to P25 TiO 2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer from the conduction band of excited TiO 2 to Au@Ag NRs leading to effective separation of electron–hole pairs. This mechanism has been proved by transient absorption spectroscopy and photo-electrochemical (PEC) measurements. The time resolved photocurrents of P25 TiO 2 NPs is ~ 13 times higher that of Au@Ag@TiO 2 , indicating that a fraction of the photogenerated electrons of TiO 2 driven by UV light transfer to Au@Ag nanocores instead of transporting entirely to the ITO substrates. The ultrafast transient absorption and pump-probe measurements demonstrated a faster decay in Au@Ag@TiO 2 NRs compared to pure TiO 2 system, indicating that the photogenerated electron–hole recombination in TiO 2 is substantially suppressed by Au@Ag@TiO 2 NRs attributed to the effective trapping of the photogenerated electrons by the Au@Ag cores. Graphic Abstract Au@Ag@TiO 2 nanocomposites with core-shell structure have been prepared and its UV light–driven H 2 generation rate has been demonstrated 14 times enhancement compared to P25 TiO 2 at the same experimental conditions. The improved photocatalytic performance was due to the charge transfer, which has been proved by photocurrent measurement and the ultrafast transient absorption and pump-probe measurements.
研究领域:
材料科学
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纳米技术
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光化学
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催化
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DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 97
·79342-79347
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IF 3.84
Xingrong Xiao,Hui Yang,Nuoxin Xu,Liang Hu,Qilong Zhang
Ag@TiO2 core–shell nanoparticles were synthesized as fillers using a simple vapor-thermal method. Based on the nanoparticles, the P(VDF-HFP)/Ag@TiO2 hybrid films were first prepared by embedding Ag@TiO2 nanoparticles in a poly(vinylidene fluoride co-hexafluoropropylene) [P(VDF-HFP)] matrix. Microstructural and thermal analysis confirmed that Ag nanoparticles had been successfully coated by TiO2 shells and that the thickness of the shell layer was about 8–10 nm. The Ag@TiO2 nanoparticles act as nucleation sites to promote crystallization of the polymer matrix without changing its structure. The P(VDF-HFP)/Ag@TiO2 composite exhibited enhanced dielectric properties over a wide frequency range, and the dielectric permittivity of the polymer nanocomposites is enhanced by ∼300% over the P(VDF-HFP) matrix at a low filler loading of 10 vol%. Moreover, P(VDF-HFP)/Ag@TiO2 also exhibit a higher dielectric constant than P(VDF-HFP)/Ag, P(VDF-HFP)/TiO2 and P(VDF-HFP)/Ag/TiO2 blend composites while maintaining a low loss tangent (below 0.03 at 1 kHz) to achieve a duplex polarization effect.
研究领域:
材料科学
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电气工程
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高影响因子
Water
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2025
·Vol. 17
·期 2
·155
·
IF 3
Yuanyuan Shi,Yi Xie,Jun Xia,Xiaolin Zhang,Hui Cheng,Jialin Chen
Ubiquitous nitrate (NO3−) in groundwater sources is considered a hazard compound for human health. Photo-catalytic reduction by Ag-TiO2/formic acid/visible light represents an emerging method for NO3−removal without secondary pollution. In this contribution, the removal of NO3−by photo-catalytic reduction and the selectivity of N2were systematically investigated under varied conditions, including concentrations of Ag-TiO2, NO3−, and formic acid (HCOOH). The removal efficiency of NO3−reached 84.47%, 82.68% of which was converted to N2under the optimal conditions: NO3−at 50 mg-N/L, Ag-TiO2at 1.0 g/L, HCOOH at 20.05 mmol/L, and reaction time at 120 min. The removal of NO3−was enhanced mainly by CO2−rather than by photo-generated electrons or HCOO−. The results of this study indicated that the production of ·CO2−by Ag-TiO2and HCOOH under visible light catalysis can achieve efficient NO3−removal.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Jie Yang,Ling Zhou,Xin-Yue Wang,Gao Song,Li-Jun You,Ju-Mei Li
Herein, the robust core-satellite Ag/TiO 2 /Ag composite nanospheres were successfully developed. We firstly fabricated large silver nanoparticles with sufficient plasmonic activity as cores and then encapsulated uniform titanium dioxide interlayer shell around Ag cores, which serves as the highly functionalized substrates to achieve uniform and plentiful surface chemical properties. Next, the outer shell of small silver satellites was formed in-situ via controllable reduction of AgNO 3 by n -butylamine, which acts as the remarkable enhancer for surface enhanced Raman scattering (SERS). The Ag/TiO 2 /Ag composite nanospheres with exceptional SERS sensitivity were easily prepared via facilely tuning the coverage and grain sizes of silver satellites. Then the optimized Ag/TiO 2 /Ag composite nanospheres were employed to quantitatively detect methylene blue (MB) in solution. The results showed good linear relationship between SERS intensities and logarithm concentrations of MB and the limit of detection is low to 10 −10 M. Moreover, the highly uniform and robust Ag/TiO 2 /Ag composite nanospheres display outstanding reproducibility (RSD = 4.02%) and highly storage stability. Owing to the intrinsic catalytic activity of small Ag satellites, Ag/TiO 2 /Ag nanospheres were further applied to effectively follow the degradation reaction process of crystal violet by SERS. Altogether, the core-satellite Ag/TiO 2 /Ag nanospheres present multiple SERS application potential in various fields, such as quantitative chemical analysis, trace detection of pollutants and in-situ reaction monitoring.
研究领域:
材料科学
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分析化学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2015
·
IF 4.529
Jiadong Xiao,Yongbing Xie,Qingzhen Han,Hongbin Cao,Yujiao Wang,Faheem Nawaz,Feng Duan
A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag + /TiO 2 suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p -benzoquinone dramatically blocked the degradation, confirming superoxide radicals ( O 2 − ) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between O 2 − and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of O 2 − and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by O 2 − , while O 2 − preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by O 2 − could simultaneously occur in p -chlorophenol degradation, consequently leading to its highest rate constant. Possible reactive positions on the phenolic compounds were also detailedly uncovered.
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
Micromachines
·
2023
·Vol. 14
·期 10
·1815
·
IF 3.4
Qian-Kun Li,Yue Li,Yan-Jun Wang,Jin-Yong Qi,Yan Wang,Yao-Dong Liu,Xue-Qing Liu
Titanium dioxide photocatalysts can break down pollutants using natural light. They possess notable light stability, chemical stability, and catalytic effects, thus leading to extensive research worldwide. However, the limited light absorption range of titanium dioxide and their inefficiencies in generating and transporting photogenerated carriers hinder the enhancement of their photocatalytic performance. In this study, we employ a femtosecond laser composite processing method to create an Ag-TiO2nanoplate composite catalyst. This method doubles the catalytic efficiency compared with the structure processed solely with the femtosecond laser. The resulting Ag-TiO2nanoplate composite catalysts show significant promise for addressing environmental and energy challenges, including the photodegradation of organic pollutants.Keywords:femtosecond laser;hierarchical micro-/nanostructures;photocatalyst;titanium dioxide
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
NANO
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2021
·
IF 1.556
M. M. Xia,J. Li,Y. Y. Zhang,D. N. Kang,Y. L. Zhang
Nanosized TiO 2 has been actively developed as a low-cost and environment-friendly anode material for lithium-ion batteries (LIBs), but its poor electronic conductivity seriously restricts its practical applications. This drawback is addressed in this work by the fabrication of one-dimensional mesoporous graphene@Ag@TiO 2 composite nanofibers as anode materials for high-performance LIBs. The materials were prepared via electrospinning combined with annealing treatment, and the effects of graphene addition on the microstructure and electrochemical performance of the resulting mesoporous graphene@Ag@TiO 2 nanofibers were investigated in detail. Ag@TiO 2 nanofibers with the optimal amount of graphene displayed a maximum initial discharge capacity of 4 9 0 . 5 mAh ⋅ g − 1 at 1 0 0 mA ⋅ g − 1 and retained a discharge capacity of 2 0 9 . 1 mAh ⋅ g − 1 at 1 0 0 mA ⋅ g − 1 after 100 cycles. These results reflect the excellent cycling stability of the material. The average specific discharge capacity of the nanofibers ( 9 7 . 6 mAh ⋅ g − 1 at 1 0 0 0 mA ⋅ g − 1 ) was two-fold higher than that of samples without graphene, and their discharge capacity returned to 2 5 3 . 8 mA ⋅ g − 1 (approximately 9 6 . 2 mA ⋅ g − 1 for other nanofibers) when the current density was recovered to the initial value ( 4 0 mA ⋅ g − 1 ) . Electrochemical impedance spectroscopic measurements confirmed that the conductivity of the electrode was 6 . 3 × 1 0 − 1 S ⋅ cm − 1 , which is higher than that of bare mesoporous Ag@TiO 2 ( 1 . 9 9 × 1 0 − 5 S ⋅ cm − 1 ). Thus, one-dimensional mesoporous graphene@Ag@TiO 2 nanofibers can be regarded as a promising anode material for LIBs.
研究领域:
材料科学
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电化学
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能源存储
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DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2019
·
IF 3.834
Yaqi Hou,Shengyan Pu,Qingqing Shi,Sandip Mandal,Hui Ma,Shengyang Xue,Guojun Cai,Yingchen Bai
New approaches and practices to improve photocatalytic efficiency of materials for remediation of organic and inorganic pollutant has become a top priority. We have developed a graphene-oxide based ternary composite Ag/TiO 2 /rGO as a green catalyst, and the photocatalytic oxidation and reduction efficiency of the catalyst was thoroughly evaluated for Cr(VI) and tetracycline (TC) remediation in water as potential contaminants. The results suggested that the electronic coupleing system exhibits excellent photocatalytic activity, mainly due to affecting light absorption and higher e − / h + separation efficiency. The photocatalytic activity of the silver-deposited graphene-supported silver and titanium dioxide was 4.3 and 2.5 times for Cr (VI) and TC remediation, respectively. Furthermore, the service life of the photocatalyst was also evaluated within five recycling studies, indicating that the efficiency of the obtained photocatalyst was maintained above 80%. Electron paramagnetic resonance spectroscopy and the addition of free radical scavengers confirmed that e − act as reducing agents and may be the key (O 2 ·− ) to the degradation process. The photocatalytic mechanism was proposed based on the studies obtained. Green catalysts based on graphene-based ternary composites developed in this work can provide effective and economic remediation at higher scale and offer practical application of photo catalysis technology.
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
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2025
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IF 5.4
Zheng Li,Jie Li,Jing Guo,Fucheng Guan,Xin Zhang,Qiang Yang,Da Bao,Xinbin Ji,Yihang Zhang,Minghan Li,Jiahao He,Yi Xu
Silver-doped titanium dioxide (Ag-TiO 2 ) demonstrates superior photocatalytic degradation capabilities, making it an ideal material for eliminating organic dyes. In this study, a nanofiber material exhibiting both high-efficiency photocatalytic degradation performance and antibacterial activity was successfully fabricated as polyvinyl alcohol nanofibers modified with protocatechualdehyde and loaded with silver-modified titanium dioxide (Ag-TiO 2 /DPVA NFs). The heterojunction structure of Ag-TiO 2 significantly broadens the visible light absorption range of TiO 2 (from 200 to 350 nm to 200–800 nm). Experimental results indicate that under visible light irradiation, Ag-TiO 2 /DPVA NFs achieved an 89 % degradation rate of Rhodamine B (Rh B) within 6 h (with C/C 0 reduced to 0.11), which is significantly superior to TiO 2 /DPVA NFs. Moreover, Ag-TiO 2 /DPVA NFs exhibited antibacterial rates of 99.1 % against Staphylococcus aureus ( S. aureus ) and 98.3 % against Escherichia coli ( E. coli ), demonstrating excellent antibacterial performance. Ultimately, the obtained Ag-TiO 2 /DPVA nanofibers demonstrate great potential for simultaneously achieving photocatalytic and antibacterial applications in the field of applications in water remediation.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 35
·35900-35912
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IF 2.914
Deng Hongyu,He Huan,Sun Shijie,Zhu Xintong,Zhou Dongxu,Han Fengxia,Huang Bin,Pan Xuejun
TiO 2 nanoparticle-doped Ag (Ag/TNPs) have good photocatalytic properties based on localized surface plasmon resonance (LSPR) effect. The effluent organic matter (EfOM) can be easily activated by photo-excitation to promote pollutant photodegradation, but excessive EfOM has an inactive effect. Herein, the purpose of this paper is to investigate the changes of photocatalytic performance by Ag/TNPs in the presence of EfOM. Three Ag/TNPs made by condensation crystallization or rotary evaporation crystallization using the sol–gel method were conducted in photocatalytic degradation of methyl orange (MO). The Ag/TNPs crystallized by condensation had greater separation rate of photogenerated electron–hole pairs and photocatalytic degradation of MO with high load rates of binding Ag and TiO 2 than those formed by rotary evaporation crystallization. Indeed, EfOM could be excited to produce the active substances under illumination resulting in the promotion of MO degradation. However, contrary to previous speculation, no additive effect of MO photodegradation was observed with the addition both of EfOM and Ag/TNPs at different pH values (5~9) and ion strength (0~0.4 mol L −1 ). It can be explained that the EfOM changed the morphology and active sites in Ag/TNPs’ surface. Meanwhile, EfOM could be consumed and degraded by Ag/TNP photocatalysis leading to the concentration of free radicals to decrease. This study revealed a nonsynergistic effect between nanomaterial and EfOM for photocatalysis. EfOM would have a negative effect on photocatalytic degradation of organic compounds by Ag/TNPs in the aquatic environment.
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研究领域:
环境科学
·
材料科学
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DOI
PubMed
高影响因子
WATER RESEARCH
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2022
·
IF 13.4
Cheng Hou,Xinbai Jiang,Dan Chen,Xiaoyu Zhang,Xiaodong Liu,Yang Mu,Jinyou Shen
Due to the pivotal role of Ag-TiO 2 /biofilm/nitrate interface, enhanced visible light-assisted biodegradation of tetracycline (TC) in anoxic system was realized through both batch experiment and long-term operation in this study. The results of the batch experiment elucidated that 50 mg L −1 TC could be completely removed within 10 h in Ag-TiO 2 /biofilm/nitrate system. The continuous flow experiment was operated for 75 d to evaluate the performance and stability of Ag-TiO 2 /biofilm/nitrate system. TC removal efficiency in Ag-TiO 2 /biofilm/nitrate system was as high as 92.4 ± 1.6% at influent TC concentration of 50 mg L −1 TC and hydraulic retention time (HRT) of 10 h, which would be attributed to the promoted separation of photoholes and photoelectrons at the presence of nitrate as electron acceptor. Facilitated electron transfer between semiconductor and biofilm was beneficial for enhancing TC biodegradation, thus lowering toxicity of intermediate products and promoting microbial activity. Moreover, the species related to TC biodegradation ( Rhodopseudomonas, Phreatobacter and Stenotrophomonas ), denitrification ( Thauera ) and electron transfer ( Delftia ) were enriched at Ag-TiO 2 /biofilm/nitrate interface. Besides, a possible mechanism involved in enhanced TC degradation and nitrogen removal at Ag-TiO 2 /biofilm/nitrate interface was proposed. This study provided a novel and promising strategy to enhance recalcitrant TC removal from industrial wastewater.
研究领域:
环境科学
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水处理
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生物技术
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微生物学
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光化学
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DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Hongli Fang,Yuanqing Kang,Shaotang Yuan,Miaomiao Zhang,Zebao Rui
Titanium dioxide (TiO 2 ) is a widely used low-cost and stable photocatalyst, but its wide bandgap and low quantum efficiency usually lead to poor photocatalytic performance. Herein, one-step solid state calcination and reduction method was proposed for simultaneously introducing surface defects and loading Ag nanoparticles (NP) on TiO 2 . The as-obtained black TiO 2-x supported Ag NP (or Ag/TiO 2-x ) holds a narrow bandgap to respond to the full solar spectrum due to the presence of high concentration surface vacancies, enhanced light absorption through the surface plasmon resonance effect of Ag NP, and satisfactory photothermal effects. Moreover, such a one-step solid state synthesis method leads to closely linked interface and enhanced charges transfer between Ag NP and TiO 2-x . Accordingly, Ag/TiO 2-x exhibits robust photothermal synergistic VOCs degradation performance with a toluene degradation rate 6 times higher than the reference Ag/TiO 2 (DP) prepared by the conventional solution method.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）