FUEL
·
2018
·
IF 4.908
Riyang Shu,Biqin Lin,Chao Wang,Jingtao Zhang,Zhengdong Cheng,Ying Chen
Noble metal catalyst has an outstanding catalytic activity on the hydrodeoxygenation (HDO) process, but its high cost limits large-scale application. Herein, we put forward a novel photochemical method to prepare the highly dispersed Pt/TiO 2 catalyst with a low metal loading. And it presented an efficient performance on the HDO of phenolic compounds and real bio-oil. Guaiacol could be converted into cyclohexane with 95.1% selectivity at 280 °C under 1 MPa H 2 atmosphere. Characterization results revealed that the high Pt dispersion was the critical factor for the high catalytic activity. And the photochemical method preferred to achieve high metal dispersion due to the room temperature condition. Other typical phenolic monomers and dimers were able to transform into hydrocarbons with most yield above 80%, wherein not only the deoxygenation step, but also the cleavage of ether bonds can be realized in one pot. This catalytic system was also effective on the upgrade of bio-oil derived from the pyrolysis of cotton straw. Hydrocarbon content increased to 33.80% from 11.33%. Alkylphenols content increased to 51.38% from 27.86%. These two products can be used as value-added fuels and chemicals, respectively. Guaiacols and syringols were completely converted into alkylphenols and hydrocarbon. The amount of other oxygenated compounds also decreased significantly. This simple and active catalytic system is potential to apply widely for the upgrade of raw bio-oil.
研究领域:
催化化学
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可再生能源
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Wen Luo,Jing Rong,Wanxia Zhao,Keke Kang,Lulu Long,Xiaojiang Yao
CeO 2 –TiO 2 catalysts with four different morphologies were successfully synthesized by a hydrothermal method and tested for selective catalytic reduction of NO x with NH 3 (NH 3 –SCR). For the four catalysts, CeO 2 –TiO 2 nanocubes (CT–NC) and nanorods (CT–NR) preferentially exposed {1 0 0} and {1 1 0} facets, respectively; furthermore, nanosheets (CT–NS) and nanospheres (CT–NH) mainly exposed {1 1 1} facet. Interestingly, CT–NH catalyst showed the best NH 3 –SCR performance and the NO x conversion exceeded 97% at 325 °C. Through a series of characteristic methods manifested that the short–range ordered structure of Ce–O–Ti in CT–NH catalyst provided stronger surface acidic sites to promote the high–temperature activity. Moreover, the abundant Ce 3+ species and appropriate reduction ability on {1 1 1} facet of CT–NH catalyst also caused outstanding de NO x activity. Reaction mechanism study showed that the Langmuir–Hinshelwood (L–H) mechanism and Eley–Rideal (E–R) mechanism existed simultaneously on all catalysts in NH 3 –SCR reaction. Meaningfully, two types of E–R mechanism were present on CT–NH catalyst, while L–H mechanism was dominant.
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Jiali Zhou,Ge Li,Hongfei Li,Ziran Ma,Shuang Liu,Xiaolong Tang
Sintering is among the most challenging obstacles preventing the development of platinum catalysts that highly effective for hydrocarbon combustion at low temperatures. To overcome this obstacle, a Pt@TiO 2 catalyst with platinum nanoparticles encapsulated by TiO x overlayers was synthesized in this article, via melamine-mediated calcinations at 800 °C in air. Being physically constrained (“protected”) and electronically buffered (“Pt x + /Pt 0 ↔ Ti 3+ /Ti 4+ ”) by the thermally stable TiO x , this catalyst preserved a large amount of reactive metallic Pt 0 sites, which therefore exhibited obviously higher activity for C 3 H 8 and C 3 H 6 combustion in comparison with conventional supported Pt/TiO 2 catalysts. Moreover, steam and SO 2 in the reaction atmospheres caused reversible influences on the catalytic performance of this sample, indicating the high practical potential of such a recipe for the design of platinum catalysts with superior activity and durability for hydrocarbon combustion.
研究领域:
催化化学
·
材料科学
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DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Hangjun Zhang,Yinan Zhang,Yuchi Zhong,Jiafeng Ding
Polychlorinated dibenzo-p-dioxins (PCDDs), characterized by their extreme toxicity, high persistency and bioaccumulation, regard as one of the most concerned environmental pollutants on the priority list. In this study, microwave-hydrothermal and photoreduction methods were adopted for fabrication of ternary Au@Fe/TiO 2 composites for removal of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) under UV–Vis light irradiation. The acquired materials were characterized and analyzed by XRD, TEM, XPS, UV–Vis DRS, PL , etc. As a result, the 1%Au@1%Fe/TiO 2 exhibited much higher photocatalytic activity that 96.3% of 2,8-DCDD was removed within 160 min with respect to that of Fe/TiO 2 (3.0 times) and TiO 2 (5.5 times). It revealed the active substances might be produced, which were verified by ESR analysis. In a comparison, the 1%Au@1%Fe/TiO 2 also exhibited high activity in that 97.2% of 2,8-DCDD was removed within 240 min under an anoxic atmosphere. The 1%Au@1%Fe/TiO 2 systems were all pH-dependent that 2,8-DCDD could be fully degraded in neutral conditions. The results of repeatability on 1%Au@1%Fe/TiO 2 showed that the sample was high stability. Fe doping improved the charge separation of TiO 2 and Au modification improved the activity via SPR effect and Mott-Schottky barrier. The degradation mechanisms and pathways were proposed and discussed in detail. The current work develops a new approach on photocatalytic oxidation and reductive dechlorination of dioxins and may open a new opportunity to extend the application range of TiO 2 catalysts.
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
Carbon Letters
·
2024
·
IF 5.5
Liu Rui,Zhang Xin,Han Xue,Sun Yuan,Jin Shuang,Liu Ri-jia
Fe 3 O 4 /g-C 3 N 4 /TiO 2 catalyst has been fabricated using a simple ultrasonic method with high photocatalytic activity. The morphology, structure and optical properties of Fe 3 O 4 /g-C 3 N 4 /TiO 2 were systematically investigated by a variety of characterization techniques. The optimum degradation conditions were investigated by degrading tetracycline (TC) under visible light irradiation. The results showed that the degradation efficiency was the highest when the initial TC concentration was 5.0 mg/L, the pH value was 11 and the catalyst dosage was 1.0 g/L. After 100 min of visible light irradiation, the degradation efficiency of TC achieved at 73.61%, which was 1.64 and 1.19 times that of g-C 3 N 4 and Fe 3 O 4 /g-C 3 N 4 , respectively. Moreover, Fe 3 O 4 /g-C 3 N 4 /TiO 2 had good stability and recyclability. The results of capture experiments showed that ‧O 2 − and ‧OH were the main active species during the photocatalytic process, and a possible photocatalytic reaction mechanism of Fe 3 O 4 /g-C 3 N 4 /TiO 2 catalyst was proposed. This study provides a new way to improve the photocatalytic performance of g-C 3 N 4 , which has great potential in degrading pollutants such as antibiotics in wastewater.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2020
·
IF 5.627
Fuchang Gao,Zuwei Xu,Haibo Zhao
In this paper, flame spray pyrolysis (FSP) is used to synthesize Pt/TiO 2 catalysts with surface-supported isolated Pt atoms through elaborate precursor/solvent formulation and flame temperature history control. It is a pivotal factor to this FSP process that there is a major distinction on saturated vapor pressure between two components (Pt species and Ti species), and thereby they exist as gas phase and particle phase at a certain temperature range, respectively. When the flame is quenched to ambient temperature with cold sheath gas , Pt species of gaseous PtO 2 (being in the vapor phase above 723 K) condense into deposition state on the surface of TiO 2 nanoparticles . Combined with X-ray photoelectron spectroscopy (XPS) analysis and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) detection, we identify that Pt atoms are dispersed and anchored on the catalyst surface . Single-atom Pt dispersed Pt/TiO 2 catalysts can be well achieved by controlling the loading at a very low level, which offers an effective way to maximize the atom economy for surface catalysis of scarce noble metals. In this work, considering that Pt as the best co-catalyst of hydrogen evolution, the FSP-made Pt/TiO 2 catalysts are tested in a photocatalysis water splitting system aiming to a simple and attractive means of renewable hydrogen production . The highest activity presents in 0.1Pt/TiO 2 with 0.1% molar ratio of Pt to Ti, reaching 108.5 times of the benchmark sample from commercial flame-made TiO 2 (P25). The high activity is attributed to the fact that the isolated Pt atom serves as the main active site for photocatalysis hydrogen evolution. Therefore, the performance and cost efficiency of catalysts are greatly improved by the FSP, mainly ascribed to engineering atomically dispersing Pt on the support surface.
研究领域:
材料科学
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化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
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IF 3.131
Boqiong Jiang,Beilong Lin,Zhiguo Li,Shuang Zhao,Ziying Chen
A series of Mn/TiO 2 catalysts were prepared by ultrasonic spray pyrolysis (USP) method for selective catalytic reduction (SCR) of NOx from flue gas at low temperatures. The highest activity of Mn/TiO 2 was obtained with a Mn/Ti ratio of 0.5. When Fe was doped into Mn(0.5)/TiO 2 , the NOx conversion rate on Fe(0.05)-Mn(0.5)/TiO 2 was increased by approximately 10 % at 120–180 °C. The samples were characterized by XRD , SEM , H 2 -TPR, and N 2 adsorption analyses. Results revealed that Mn(0.5)/TiO 2 with Mn/Ti ratio of 0.5 presented the lowest crystallinity , the highest surface area, and the highest redox ability. Although the surface area was significantly decreased by Fe doping, it also reduced the crystallinity and crystal size of the catalysts, thereby increasing the O concentration on the surface of catalyst. Moreover, Fe(0.05)-Mn(0.5)/TiO 2 displayed a higher redox ability than the other catalysts. At 120–240 °C, the activation energy decreased from 27.65 kJ/mol on Mn(0.5)/TiO 2 to 14.46 kJ/mol on Fe(0.05)-Mn(0.5)/TiO 2 , thereby facilitating the activation of the reaction on Fe(0.05)-Mn(0.5)/TiO 2 . Despite that the NO and NH 3 adsorptions were lower on Fe(0.05)-Mn(0.5)/TiO 2 than on Mn(0.5)/TiO 2 , the intermediates on Fe(0.05)-Mn(0.5)/TiO 2 , particularly nitrates, were easily activated to participate in the reaction, leading to increasing catalytic activity.
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2016
·Vol. 41
·期 2
·569-578
·
IF 3.277
Yuejiao Qin,Suhang Xun,Liangliang Zhan,Qingqing Lu,Minqiang He,Wei Jiang,Hongping Li,Ming Zhang,Wenshuai Zhu,Huaming Li
A series of WO3/TiO2 catalysts with a pore structure were successfully synthesized. The catalysts were systematically characterized and it was found that different calcination temperatures had great effects on the pore structure of the catalysts. The catalyst presented a mesoporous structure after calcining at 550 °C (expressed as 550-WO3/TiO2) and had the largest specific surface area among the mesoporous catalysts. The oxidation of dibenzothiophene (DBT) with 550-WO3/TiO2 catalyst reached 100% under optimum conditions. After recycling for 6 times, the oxidation of DBT could still achieve a DBT removal of 96.7%, suggesting that the catalyst had good stability and recycle performance. In addition, DBT sulfone (DBTO2) was proven to be the only oxidation product of DBT after the reaction, as observed by the GC-MS analysis. The catalytic activities of the catalyst on different substrates were also investigated, and the activities decreased in the order: DBT > 4-MDBT > 4,6-DMDBT > BT.
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 39
·18744-18750
·
IF 3.925
Dawang Chu,Hui Zhou,Zhicheng Luo
Selective conversion of glycerol to lactic acid requires the synergistic activation of C–H, C–O, and O–H. Herein, we report an inexpensive Fe–Cr/TiO2 catalyst that achieves lactic acid formation with a high selectivity of 60.5%. By changing the Fe/Cr ratios and reduction temperatures, the structures of Vő and Vő-OH were altered, which determined the overall oxidation–dehydration–isomerization process. The in situ ATR-IR experiments confirmed the activation of glycerol by adsorbing the primary −OH, and a series of control experiments verified that Fe was responsible for the cleavage of C–H and O–H, while CrOx catalyzed the activation of C–O and C–H. This work designs a hydrothermal catalyst with multifunctional ability, which may guide the rational catalyst design for the selective oxidation of glycerol to lactic acid.
研究领域:
催化化学
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材料科学
·
绿色化学
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2023
·
IF 2.8
Wang Yanghui,Jin Luyao,Xu Xintao,Li Jiaying,Fan Kaihao,Hu Bo,Shen Yi,Liu Xuesong
In this paper, MnO x /TiO 2 catalysts with different manganese contents were prepared by using vacuum over-impregnation method to support manganese on TiO 2 support. However, the activity temperature window was narrow and the denitrification efficiency was only 265–365 °C in the temperature zone above 80%. Therefore, doping W was used to improve the high temperature activity and broaden the activity temperature window. The experimental results show that the active temperature window of the catalyst is expanded to 260–550 °C when doping 20%WO 3 . The effects of tungsten doping on the structure and surface properties of the catalysts were investigated by XRD, TEM, Raman, XPS, H 2 -TPR and NH 3 -TPD. It is found that the increase of manganese content would increase the ratio of Mn 4+ and O α , and then improve the NH 3 -SCR activity at low temperature. Tungsten doping can provide more strong acid sites and improve the high temperature activity of the catalyst by inhibiting the oxidation of ammonia. Graphical Abstract
研究领域:
催化化学
·
环境科学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Wenqing Yu,Ying Wang,Hanwen Zhang,Qiao Zhang,Shengyang Wang,Zhiting Liu,Guangxing Yang,Feng Peng
The 5-hydroxymethylfurfural oxidation reaction (HMFOR) is regarded as a promising approach to produce biomass-derived highly valuable chemical products. 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) as a typical product via selective oxidation of the aldehyde group in HMF was obtained on Au/anatase and Au/rutile catalysts under photoexcited and dark states. The results show that the HMF oxidation reactivities of Au/rutile and Au/anatase were improved under visible light irradiation compared with those under dark conditions, and the increase of the activity is more obvious as the reaction temperature decreases. The kinetic studies showed that visible light irradiation reduced the energy barrier of the HMF oxidation reaction and promoted the reaction activities. The radical capture and EPR experiments were further used to explore the mechanisms of the HMF oxidation reaction under both conditions over Au/TiO2 catalysts. The evidence indicated that the main active species were 1O2 and trace amounts of •O2– under dark conditions, while the main active species were •O2–, 1O2, and h+ under visible light irradiation conditions for both Au/rutile and Au/anatase catalysts.
研究领域:
催化化学
·
生物质转化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Zhixiang Ren,Ao Li,Xinyu Lei,Zhengwei Yu,Guangying Wang,Hongliang Zhang,Huan Chen,Yin Wang,Hongming Long
As a mainstream moderate-high temperature (250–420 °C) particulate denitrification catalyst, V 2 O 5 -WO 3 /TiO 2 (VWT) is not applicable to low-temperature (60–150 °C) iron ore sintering flue gas after semi dry/wet desulfurization. In order to improve the NH 3 -deNO x performance of the VWT particle catalyst at low temperatures, a series of powder VWT denitrification catalysts doped with different content of RuO 2 (R-VWT) prepared by the wet co-impregnation method were researched, and found that the particulate catalyst service temperature (about 100 % NO conversion) is lowered from 225 °C (VWT) to below 175 °C by doping 0.5 % RuO 2 . In addition, a series of characterizations indicate that the doped RuO 2 enhances the redox performance of R-VWT and promotes the generation of more surface active intermediate monodentate nitrate, and accelerates the low-temperature surface SCR transient reaction rate.
研究领域:
环境科学
·
催化化学
✓ 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）