Nanoscale Horizons
·
2022
·Vol. 8
·期 3
·338-345
·
IF 11.684
Jie Wu,Xuetao Qin,Yu Xia,Yuanyuan Zhang,Bin Zhang,Yunchen Du,Hsing-Lin Wang,Siwei Li,Ping Xu
Transition metal sulfides (TMSs) are promising electrocatalysts for hydrogen evolution reaction (HER), while TMSs usually suffer from inevitable surface oxidation in air, and the impact of the surface oxidation on their HER catalytic activity remains unclear. Herein, we demonstrate an effective strategy for reducing the surface oxidation degree of easily oxidized CoS2 by introducing glued vanadium pentoxide (V2O5) nanoclusters, taking advantage of the preferential adsorption and strong interaction between high-valence V and O2. Combining oxidation protection and elaborate oxidation control experiments reveal that reduced surface oxidation degree of CoS2 is conducive to affording promising HER catalytic performance, as the oxidized surface of CoS2 can hinder the dissociation of water and thus is harmful to the HER process. Direct evidence is provided that surface oxidation should be carefully considered for TMS-based HER catalysts. The present work not only develops a new strategy for protecting CoS2 from surface oxidation, but also provides deep insight into the impact of surface oxidation on the HER performance of transition metal compounds.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yongsheng Jia,Donghang Chen,Yan Li,Enze Li,Long Zhao,Limin Guo
In this study, CO 2 was converted to activated carbon by the molten salt CO 2 capture and electrochemical conversion (MSCC-EC) method, and the surface oxygen content of the activated carbon was further modified for the adsorption of polar molecules (chlorobenzene) and nonpolar molecules (toluene), the role of the pore structure and surface O-containing functional groups of the adsorbents in contributing to the adsorption process was systematically investigated. The results showed that MS-AC 500-10 , MS-AC 500-15 , and MS-AC 550-15 have rich pore structures with specific surface areas of 811.56 m 2 /g, 835.35 m 2 /g, 1249.104 m 2 /g, and surface oxygen contents of about 10 %, 15 %, 15 %, respectively. The toluene adsorption capacity of MS-AC 500-10 , MS-AC 500-15 , and MS-AC 550-15 was 203.82 mg/g, 229.72 mg/g, and 358.97 mg/g, respectively, and was dominated by pore adsorption, which was positively proportional to the specific surface areas and pore volumes, the adsorption process belonged to the pseudo-first-order kinetic model. The adsorption amounts of chlorobenzene by MS-AC 500-10 , MS-AC 500-15 , and MS-AC 550-15 were 287.98 mg/g, 363.11 mg/g, and 495.41 mg/g, respectively. In addition to the pore adsorption, the oxygen content on the surface of the adsorbents had a non-negligible promotion effect on the adsorption of chlorobenzene, mainly because chlorobenzene is a polar molecule, and the asymmetric electrons on its surface have strong interactions with the O-containing functional groups on the surface of the adsorbents. Moreover, the prepared adsorbents were thermally stable, and the decay rate of adsorption performance was less than 5 % after five adsorption–desorption cycles.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2018
·
IF 9.89
Hui Chen,Lei Sun,Guo-Dong Li,Xiaoxin Zou
Surface oxygen chemistry of semiconductor metal oxides is the basis for the sensing reaction between the preadsorbed surface oxygen and the target gases or organic vapors that are to be detected, and thus fundamentally determines their sensing performances. Herein, we, for the first time, identify a novel semiconductor spinel oxide, CdGa2O4, that has suitable surface oxygen chemistry and exhibits excellent selectivity and response toward formaldehyde. Moreover, we find that a cation off-stoichiometric CdGa2O4 spinel oxide decorated with a small amount of CdO nanocrystals can further improve the formaldehyde response, without losing the selectivity. This is based on the advantages of an increased amount of adsorbed oxygen in the Ga-rich environment, as well as heterojunctions between CdO nanoparticles and Ga-rich spinel oxide. Sensing performance (e.g., selectivity and response) of the material is much better than that of most reported nanostructured metal oxides used for formaldehyde detection. Our findings propose a general approach for achieving highly selective and sensitive detection of target gases by optimizing the surface oxygen property of semiconductor oxides.
研究领域:
材料科学
·
传感器技术
·
化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Yu Guan,Yinhe Liu,Qiang Lv,Bo Wang
The selective catalytic reduction of nitrogen oxides (NO x ) by carbon monoxide (CO-SCR) is a promising way to deal with exhaust gasses. And Effective redox cycle and NO dissociation ability are crucial factors for catalytic reduction of NO x . Herein, Fe decorated CeO 2 microsphere catalysts with surface oxygen defect were synthesized by solvothermal and calcination method. Among all catalysts, 0.5Fe-CeO 2 sample showed excellent catalytic performance with efficiency near 96% for NO reduction under the condition of 550 ppmv NO, 1200 ppmv CO, and 40,000 h − 1 of GHSV. It was found that Fe doping could efficiently regulate Ce 4+ /Ce 3+ redox couple and oxygen vacancy for catalytic activity. XRD, Raman, XPS, EPR and H 2 -TPR etc. were employed to explore the physicochemical properties of samples. The results showed that Fe had been incorporated into CeO 2 by XRD, and the results of Raman spectrum and XPS indicated that Ce 4+ /Ce 3+ redox couple existed in 0.5Fe-CeO 2 catalyst. Furthermore, the H 2 -TPR spectrum displayed the formation of oxygen vacancy in the samples. N 2 adsorption-desorption isotherms indicated that the doping of Fe could enlarge the specific surface area, pore volume and pore dimeter of the samples, and thus greatly enhanced the NO adsorption and further NO catalytic reduction on catalysts. In addition, other characterization of physicochemical properties and density functional theory (DFT) calculation were performed to reveal the mechanism of NO + CO reaction. As a result, a mechanism was proposed to elucidate highly efficient NO reduction over the catalysts of Fe decorated CeO 2 microspheres. Finally, the synergistic effects of redox center and oxygen vacancy on catalytic activity enhancement were revealed. This work provides a promising way to the design of efficient catalysts for NO reduction.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Bioresource Technology Reports
·
2022
·
IF 0
Sen Lin,Yihong Guo,Lei Zhou,Hongjun Yang
Quantitative effects of surface oxidation on Cd 2+ adsorption performance of biochar derived from long-root Eichhornia Crassipes plants were systematically investigated. It was revealed that oxidation degree was positively related with the intensity of surface functional groups and harmless for the structural stability, while biochar yield would decline sharply resulting from for over-oxidization. Correspondingly, the Cd 2+ adsorption capacity exhibited an uptrend with the increasing oxidation on account of the abundant adsorption sites. Moreover, Cd 2+ adsorption on the biochar with different oxidation degrees were also investigated comprehensively, indicating adsorption performances in a similar trend highly sensitive to solution pH and ionic strength . In addition, the adsorption isotherms were found to manifest the saturated adsorption capacity for Cd 2+ increased from 0.333 mol/g to 0.487 mmol/g at 30 °C by strengthening oxidation. All synthesized biochar could keep consistent adsorption performance in multiple adsorption-desorption cycles.
研究领域:
环境科学
·
材料科学
·
生态学
✓ 已验证
DOI
ACS Applied Nano Materials
·
2024
·
IF 5.3
Aili Yuan,Tengfei Huang,Yanzhen Guo,Yaru Wei,Huili Liu,Baocheng Yang,Binbin Chang
The integrated dual-channel pathway is regarded as an ideal process for photocatalytic H2O2 production. However, it is a key scientific challenge to rationally design photocatalysts for achieving H2O2 production through such a dual-channel pathway. Here, we designed surface oxygen vacancy-modified BiOIO3 (BIO-OVs-x) with spatially separated redox reaction centers by constructing a facet heterojunction for directly utilizing O2 and H2O to photosynthesize H2O2. Under white light irradiation, optimal BIO-OVs-2 exhibited the highest H2O2 production rate of 215.5 μmol g–1 h–1, which was 3 times more than that of BiOIO3, as well as an apparent quantum yield of 5.76% at 350 nm. Photoelectrochemical experiments confirmed that the introduction of oxygen vacancies boosted the efficiency of charge separation and transfer and adjusted the band structure. Control experiments and theoretical studies elucidated photocatalytic reaction active sites and the charge transport mechanism of BIO-OV catalysts. More importantly, the introduction of oxygen vacancies in BiOIO3 reduced the free energy for OH* of the water oxidation reaction and promoted the occurrence of the water oxidation reaction. This work provides a valuable basis for the fine design of a high-performance photocatalyst and for understanding the mechanism of hydrogen peroxide production.
研究领域:
材料科学
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环境科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 15
·3611-3617
·
IF 9.125
Meng Li Liu,Lin Yang,Rong Sheng Li,Bin Bin Chen,Hui Liu,Cheng Zhi Huang
Photoluminescent (PL) carbon dots (CDs) as a new type of carbon nanomaterial have attracted increasing attention owing to their fascinating properties. Herein, we develop a facile, energy-efficient, large-scale route to prepare highly PL CDs with a quantum yield of up to 35.3% at room temperature. These PL CDs can be further separated out into green-emissive amorphous carbon nanodots (CNDs) and yellow-emissive crystalline graphene quantum dots (GQDs) through a silica gel column. Both the as-prepared CNDs and GQDs, even when having the same particle-size distribution and chemical groups, have different degrees of surface oxidation. As characterized by X-ray photoelectron spectroscopy (XPS), the yellow-emissive crystalline GQDs have a much higher surface oxidation degree than that of the green-emissive amorphous CNDs. A further finding is that the characteristic emission peaks of the CDs show an obvious red shift from 518 nm to 543 nm with the increase in the surface oxidation degree, which can be attributed to the decrease in their band gap between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO). That is, the difference in band gap is closely related to the oxidation degree of the CDs, rather than the particle size or chemical groups. Moreover, the amorphous CNDs are very easily photobleached under 140 W xenon lamp irradiation as compared to the crystalline GQDs, indicating that the photostability is dependent on the crystalline structure of the CDs, which is beneficial for the top-down design and development of suitable CDs for different application purposes.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2024
·
IF 3.7
Yun-Long Mu,Qing He,Chun-Yan Li,Da Sheng,Song-Hai Wu,Yong Liu,Hai-Tao Ren,Xu Han
Although precise regulation of the crystalline structures of metal oxides is an effective method to improve their antibacterial activities, the corresponding mechanisms involved in this process are still unclear. In this study, three kinds of cuprous oxide (Cu2O) samples with different structures of cubes, octahedra, and rhombic dodecahedra (c-Cu2O, o-Cu2O, and r-Cu2O) have been successfully synthesized and their antibacterial activities are compared. The antibacterial activities follow the order of r-Cu2O > o-Cu2O > c-Cu2O, revealing the significant dependence of the antibacterial activities on the crystalline structures of Cu2O. Quenching experiments, as well as the NBT and DPD experiments indicate that ≡CuII─OO• superoxo and ≡CuII─OOH peroxo, instead of •OH, O2•–, and H2O2, are the primary oxidizing species in the oxidative damage to E. coli. Raman analysis further confirms the presence of both ≡CuII─OO• superoxo and ≡CuII─OOH peroxo on the surface of r-Cu2O. On the other hand, the NCP experiment reveals that Cu+, instead of Cu2+, also contributes to the antibacterial process. This study provides new insight into the antibacterial mechanisms of Cu2O.
研究领域:
材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Jiaqiao Yuan,Hongyu Lu,Xiang Gong,Mingjun Chen,Hao Lai,Shuming Wen,Shaojun Bai,Dandan Wu
The development of high-efficiency beneficiation processes for ilmenite has garnered widespread attention. This study proposed the utilize of a heterogeneous Fenton catalytic technology involving H 2 O 2 and Fe 2+ to enhance ilmenite flotation. The flotation results indicated that pre-oxidation of ilmenite with H 2 O 2 -Fe 2+ before adding collector could recover over 80 % of ilmenite from titanaugite. Electron Paramagnetic Resonance and slurry iron component concentration analyses revealed that the •OH generated within the ilmenite-H 2 O 2 -Fe 2+ catalytic system could oxidize Fe 2+ to Fe 3+ . The stronger binding capability of Fe 3+ with NaOL led to a remarkable discrepancy in floatability between ilmenite and titanaugite. Zeta potential analysis further confirmed that the oxidation degree of the ilmenite surface and the adsorption of iron species were higher than those of titanaugite. Additionally, Time-of-Flight Secondary Ion Mass Spectrometry and X-ray photoelectron spectroscopy analyses provided evidence for the selective activation of ilmenite by the H 2 O 2 -Fe 2+ . Furthermore, Density Functional Theory calculations revealed that the stable adsorption of Fe 2+ and Fe(OH) 2 + offered additional active sites on the ilmenite surface for NaOL adsorption. Moreover, the adsorption of •OH significantly affected the electronic spin density of the Fe 3d orbitals of Fe atom in ilmenite, and played a crucial positive in the surface activity of ilmenite.
研究领域:
矿物加工工程
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化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Qingjing Liu,Ruisheng Wang,Ranjia Li,Xiaosheng Wang,Suoqi Zhao,Changchun Yu
Mn–Na2WO4-based catalysts with different supports were prepared using the incipient wetness impregnation method and evaluated for their oxidative coupling of methane (OCM) reaction performance. The results demonstrated that the SiO2- supported catalyst exhibited the best catalytic performance, and the introduction of H2O further enhanced its activity. Under the conditions of a feed gas mixture of CH4/O2/H2O = 6:1:24 at 800 °C and atmospheric pressure, the CH4 conversion and C2+ selectivity over the Mn–Na2WO4/SiO2 catalyst increased from 28.4% and 77.4% (without H2O) to 33.2% and 84.9%, respectively. In contrast, the catalytic activity using TiO2 and MgO supports drastically declined. Characterizations using X-ray diffraction (XRD), in situ infrared spectroscopy (In-situ IR), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), and oxygen temperature-programmed desorption (O2-TPD) revealed that the introduction of steam not only served as a diluent to decrease the partial pressures of the reactants CH4 and O2, thereby reducing deep oxidation reactions in the gas phase, but also interacted with surface oxygen species (O22–) and silica to form adjacent surface-bonded disilanol free radicals Si–OIH. This interaction facilitated the dehydrogenation and coupling of two methane molecules on the catalyst surface, resulting in the generation of C2+ products, significantly enhancing the catalytic activity and selectivity of OCM.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS ES&T Engineering
·
2024
·
IF 7.4
Shiyu Cao,Lin Zhang,Cancan Ling,Furong Guo,Meiqi Li,Chuan Liang,Jundi Cheng,Yanbiao Shi,Hongwei Sun,Lizhi Zhang
Mackinawite (FeS) is an excellent Cd(II) removal material but suffers from rapid reactivity loss. Herein, we demonstrate that rational surface preoxidation could enhance the single maximum adsorption capacity of mackinawite from 625.0 to 666.7 mg g–1 and also promote its air stability and reusability for long-term application. The Cd(II) removal processes were carefully characterized with a multifunctional in situ electrochemical device, theoretical calculation, and extended X-ray absorption fine structure (EXAFS) spectroscopy. Characterization results revealed that surface preoxidation treatment changed the Cd(II) removal mechanism from ion exchange to ion-exchange coupled surface adsorption because surface preoxidized FeS possessed abundant surface −OH sites. This extra surface adsorption process offered surface preoxidized FeS a superior long-term Cd(II) removal performance of 1290.5 mg g–1 in 5 successive cycles, much higher than that of pristine FeS (842.4 mg g–1). This study highlights the importance of surface oxidation on the Cd(II) removal performance of mackinawite and also opens a new strategy to design and produce high-performance mackinawite nanocrystals for pollutant control and environmental remediation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2024
·
IF 5.5
Linquan Dai,Bo Feng,Yutao Guo
Background Sphalerite and galena often exist in mixed form and are difficult to separate effectively. The effect of surface oxidation behavior regulation on the depression of calcium lentisulfonate (CLS) was studied in galena and sphalerite. Methods Flotation experiment, contact angle experiment, X-ray photoelectron spectroscopy (XPS) analysis and microcalorimetric experiment were used to study the effect and mechanism of modulation of surface oxidation behaviour on CLS on the depression of galena flotation. Significant findings The results show that CLS can depress both galena and sphalerite. The oxidizing agent H 2 O 2 oxidizes galena significantly faster than sphalerite. The treatment with H 2 O 2 induces the formation of more oxidation products, such as PbSO 4, on the surface of galena, enhances the adsorption of CLS and makes the surface of galena hydrophilic, thus reducing the recovery of galena in the flotation process. On the other hand, the treatment of the activator ethylenediaminetetraacetic acid (EDTA) reduces the amount of oxidation products ZnSO 4 on the sphalerite surface, and CLS loses the active site that can be adsorbed on the galena surface, making the galena surface hydrophilic. In view of the huge hydrophobicity difference between sphalerite and galena, flotation separation is achieved.
研究领域:
矿物加工工程
·
材料科学与工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）