Catalysts
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2023
·Vol. 13
·期 2
·450
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IF 3.9
Muhammad Naeem Younis,Zhiheng Ren,Chunshan Li,Erqiang Wang,Jie Li
The advancing effects of various alkali and alkaline earth metals (inclusive of K, Ca, and Sr) modified Cu/SiO2catalysts, prepared with a modified precipitation-gel method, were investigated for the production of ethanol via hydrogenation of methyl acetate. Our results showed that Sr-doped catalysts exhibited the best and most consistent results during catalytic tests. A series of techniques, including X-ray diffraction technique, Raman spectroscopy, N2adsorption/desorption, N2O titration method, FTIR spectroscopy, and H2temperature, programmed desorption and reduction (TPD and TPR), and X-ray Photoelectron Spectroscopy, which was used to check the detailed characterization of Sr modification in the catalyst and its structural impacts on the properties of the catalyst. These results demonstrated that the addition of 5%Sr could strengthen the intrinsic stability of the catalyst by formulating the appropriate ratio of Cu+/(Cu0+ Cu+) to facilitate catalytic outcome improvement. The addition of 5%Sr-30%Cu/SiO2under the most favorable conditions, resulting in the peak conversion of MA (95%) and ethanol selectivity (96%), indicates its magnificent catalytic stabilizing effects. Furthermore, the best performing catalyst was compared and tested under various conditions (LHSV and temperatures) and a 300 h long life run.Keywords:hydrogenation;methyl acetate;ethanol;strontium
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Yong Liu,Siyu Yu,Xinyu Wu,Xueyu Cao,Haojie Geng,Cuijuan Zhang,Shetian Liu
Non-precious metal catalysts suitable for hydrogen production via aqueous phase reforming (APR) of methanol show important technical and commercial value in the development of distributed, small/micro-scale on-site hydrogen production systems. They still face the challenges of reduced activity and stability due to sintering and oxidation of active metal nanoparticles , change of the surface state and collapse of the pore structure of used supports under hydrothermal conditions. To solve these problems, a series of ZnO/Ni-xCu/Al 2 O 3 (x = 0, 2, 4, 6, 8, 10) catalysts were prepared by a simple impregnation method in this work. The addition of Cu improved the reducibility of NiO, and promoted the formation of smaller and more dispersed metal particles on the surface of Al 2 O 3 , facilitating hydrogen production and hindering methane formation. Among them, the highest average hydrogen production rate (362.1 μmol‧min −1 ‧gcat −1 ) and the highest hydrogen selectivity (99%) were reached using ZnO/Ni-8Cu/Al 2 O 3 catalyst, which were 1.6 times and 20.7% higher than those obtained on the mono-metallic ZnO/Ni/Al 2 O 3 catalyst, respectively. On the other hand, the modification of Ni-8Cu/Al 2 O 3 with ZnO prevented effectively the reaction of surface water with Al 2 O 3 and inhibited the formation of boehmite phase, leading to dramatical improvement of its stability during APR of methanol with a prolonged lifetime (72 h) by 6 times. This new developed ZnO/Ni-xCu/Al 2 O 3 catalysts offer great potential for the development of commercial catalysts to produce hydrogen from APR of methanol.
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ChemCatChem
·
2018
·Vol. 11
·期 3
·1123-1130
·
IF 4.674
Xiao-Li Li,Guo-Hui Yang,Meng Zhang,Xiao-Feng Gao,Hong-Juan Xie,Yun-Xing Bai,Ying-Quan Wu,Jun-Xuan Pan,Yi-Sheng Tan
Graphical Tuning selectivity : Cu/SiO 2 was prepared by ammonia evaporation and used as catalyst for the direct synthesis of ethanol from CO hydrogenation. Both the Cu + /(Cu + +Cu 0 ) values and copper crystallite sizes had significant effects on the selectivity towards ethanol. Cu/SiO 2 catalyst was prepared by the ammonia evaporation method for the direct synthesis of ethanol from CO hydrogenation. The catalyst exhibited the initial ethanol selectivity as high as 40.0 wt %, which dramatically decreased from 40.0 to 9.6 wt % on the stream of 50 h. XRD, XPS, TEM and N 2 O titration techniques were employed to elucidate the ethanol selectivity change and catalyst structure evolution during reaction process. The experiment and characterization results indicated that both Cu + /(Cu + +Cu 0 ) value and copper crystallite size had great effects on the ethanol selectivity. During the initial 38 h, the ethanol selectivity obviously decreased from 40.0 to 18.2 wt %, and Cu + /(Cu + +Cu 0 ) value on the catalyst surface rapidly dropped from 0.67 to 0.39, while the copper crystallite size remained almost unchanged. However, during the reaction period of 38–50 h, the Cu + /(Cu + +Cu 0 ) value possessed no distinct change, but a further decrease in ethanol selectivity and a rapid aggregation in Cu particles were observed simultaneously. The present systematic investigation demonstrated that the decrease of Cu + /(Cu + +Cu 0 ) value was the main factor for the loss of ethanol selectivity during the initial 38 h, whereas the rapid growth of Cu particles during the reaction period of 38–50 h were mainly contributed to the further decline of ethanol selectivity.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Sheying Dong,Qian Zheng,Guiqi Huang,Xiaohong Wang,Tinglin Huang
A new method based on coordination polymer [Cu(bipy)(SO4)]n (CP) and functionalized CP, which have a low cost and a easy preparation for selective removal of two organic pollutants in aqueous solution was proposed. Experimental results indicated that CP had excellent adsorption capacity for Alizarin red S (ARS) (1051 mg g–1) and Acid orange 7 (AO7) (989 mg g–1) by ion-exchange interaction. It was found that the kinetic and equilibrium adsorptions were well-modeled using the pseudo-second-order kinetic and the Langmuir isotherm model, respectively. Furthermore, the anionic surfactant (sodium dodecyl sulfonate, SDS) was introduced into the chain structure of CP by anionic exchange to form functionalized CP material (CP/SDS) to remove another type of organic pollution which was representative fluoroquinolone antibiotics like Enrofloxacin (EF), Sparfloxacin (SF), and Levofloxacin lactate (LL) from aqueous solution. Several conditions affecting the removal efficiency of three antibiotics including the composition ratio of SDS in adsorbent, pH, adsorbent dosage, and ionic strength were investigated. Due to the hydrophobic effect of the long methylene chain units in SDS molecular and cyclopropyl, phenyl and alkyl groups in antibiotics, the CP/SDS adsorbent have remarkable adsorption capacity for three antibiotics compared to some commercially available adsorbents, and it requires only 10 min to reach adsorption equilibrium. Thus, the results of this work demonstrate that CP and functionalized CP as the promising adsorbent materials can selectively remove two types of organic pollutants from aqueous solution. In the meantime, it exhibits the alternative exploitation approach for one-dimensional CP in environmental applicability.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Xue Hu,Xidong Liu,Xiaodan Zhang,Haiyan Cao,Yuming Huang
By tuning the photoluminescence of alloy Cu/Ag nanoclusters (NCs) and thiamine (VB 1 ) simultaneously through MnO 2 nanowires, we report a simple and label-free ratiometric fluorescent platform for sensitively and selectively sensing of glutathione (GSH). Ag doping of Cu NCs significantly enhances the quantum yield (QY, about 2-fold enhancement), oxidation resistance to air, storage stability (60 days versus 1 day), photostability and salt stability of the resultant Cu/Ag NCs. Impressively, MnO 2 nanowires quench the fluorescence of Cu/Ag NCs, while they enhance the fluorescence of nonfluorescent VB 1 via oxidation reaction between VB 1 and dissolved oxygen to produce oxVB 1 as a nanozyme catalyst. Upon introduction of GSH as a target, the MnO 2 nanowires are reduced to Mn 2+ and lose their quenching capacity and oxidase-like activity, resulting in FL recovery of Cu/Ag NCs and fluorescent decrease of oxVB 1 . Hence, a ratiometric luminescence signal is obtained, providing a novel ratiometric fluorescent strategy for detecting GSH through target induced regulation of the catalytic activities and quenching ability of MnO 2 nanowires. The sensor exhibited a wide linear concentration range (10 nM to 70 μM) for GSH with a detection limit of 6.5 nM. The ratiometric sensor was successfully used for GSH detection in biological samples.
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FOOD CONTROL
·
2019
·
IF 4.248
Baoshan He,Dandan Yan
In this work, an electrode which comprises Au nanoparticles (AuNPs) and electrochemically reduced graphene oxide (ERGO) recombined Cu based metal-organic framework (Cu-TDPAT) was prepared for nitrite detection. The structure and constituent of the modified material were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and FT-IR. The electrochemical behavior of nitrite at the modified electrode was performed by cyclic voltammetry and electrochemical impedance spectroscopy. The results indicated that the oxidation process of nitrite happened at recommended electrode had a superior response. The proposed electrode showed high electrocatalytic capacity toward nitrite oxidation with a wide linear working range (0.001–1000 μmol·L −1 ) and a detection limit of 0.006 μmol·L −1 . Finally, the sensor was successfully applied to detect nitrite in real sample and achieved desirable recovery rate, showing its potential application in real-time detection of food .
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-14
·
IF 4.011
Dong Fang,Meng Yu,Han Weiliang,Zhao Haijun,Tang Zhicheng
Here, we synthesized a series of Cu/CeO 2 catalysts with different morphology and size, including Cu/CeO 2 nanospheres (Cu/CeO 2 -S), Cu/CeO 2 nanoparticles (Cu/CeO 2 -P), Cu/CeO 2 nanorods (Cu/CeO 2 -R) and flower-like Cu/CeO 2 microspheres (Cu/CeO 2 -F) to systematically explore the structure-activity relationship in CO oxidation. Crucially, the effect of morphology, crystal size, Ce 4+ /Ce 3+ species, oxygen vacancies derived from the removal of lattice oxygen (O latt ) species in CeO 2 and lattice defect sites on CO activity was revealed through various characterizations. It was clearly discovered that the activity of these catalysts was as follows: Cu/CeO 2 -R > Cu/CeO 2 -P > Cu/CeO 2 -S > Cu/CeO 2 -F, and the Cu/CeO 2 -R catalyst preferentially showed the best catalytic performance with a 90% conversion of CO even at 58 °C, owned the smaller particles size of CeO 2 and CuO, and exhibited the higher concentration of O latt species and oxygen vacancies. Besides, it is also verified that the Cu/CeO 2 -F sample exhibited the larger CeO 2 crystal size (17.14 nm), which led to the lower Cu dispersion and CO conversion, even at 121 °C (T 90 ). Most importantly, we discovered that the amount of surface lattice defect sites was positively related to the reaction rate of CO. Simultaneously, DFT calculation also demonstrated that the introduced oxygen vacancies in CeO 2 could accelerate the oxidation of CO by the alteration of CO adsorption energy. Therefore, the morphology, the crystal size, the content of oxygen vacancies, as well as lattice defects of Cu/CeO 2 catalyst might work together for CO oxidation reaction.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Dun Fu,Tonni Agustiono Kurniawan,Heng Li,Liuying Wang,Zheng Chen,Wen Li,Yuanpeng Wang,Haitao Wang,Qingbiao Li
The technical applicability of hydrochar-derived pyrolysis char-supported Cu nanoparticles composite (Cu NPs/HDPC) to the degradation of octocrylene (OC) was investigated in aqueous solutions in the presence of H 2 O 2 . The physico-chemical properties of the Cu NPs/HDPC composite before and after degradation reaction were described. The role of OH in this H 2 O 2 -led degradation was examined using electron spin resonance (EPR) technique. The possible degradation mechanisms of OC by the Cu NPs/HDPC-H 2 O 2 system and its degradation pathways were investigated. A relatively large surface area and pore volume of the HDPC (191.4 m 2 g −1 and 0.11 cm 3 g −1 , respectively) resulted in well-dispersed Cu NPs loading on the surface. The degradation efficiency of OC (50 μM) was 97.0% in the presence of Cu NPs/HDPC composite (0.5 g L −1 ) and H 2 O 2 (20 mM) at pH 5.6 in 4 h, which was significantly higher than in Cu NPs/biochar and the integrated HDPC-Cu NPs, i.e., 62.4% and 79.7%, respectively, under the same conditions (ANOVA test; p ≤ 0.05). Several oxidation by-products of the OC included benzophenone, 3,3-diphenylacrylonitrile, and others. The OH, which resulted from the Fenton-like oxidation between the Cu species and H 2 O 2 on the HDPC surface, was the predominant factor responsible for the OC degradation in the solution. The OH formation was facilitated by a single-electron transfer process from the HDPC surface, in which the Cu NPs/HDPC composite with its C OH functional group promoted the decomposition of H 2 O 2 . These findings contribute to a novel approach of cost-effective wastewater treatment by adding value to unused waste materials from agricultural industries.
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Advanced Optical Materials
·
2018
·Vol. 6
·期 10
·1701389
·
IF 7.43
Zhongyuan Guan,Aiwei Tang,Peiwen Lv,Zhenyang Liu,Xu Li,Zhan'ao Tan,Tasawar Hayat,Ahmed Alsaedi,Chunhe Yang,Feng Teng
A series of multinary Cu-In-Zn-Se-S nanocrystals (NCs) are synthesized via a phosphine-free and one-pot approach, in which the Se powder and 1-dodecanethiol (DDT) are used as chalcogenide sources, respectively. The X-ray photoelectron spectra are used to confirm the presence of lattice sulfur in the as-obtained products. The emission color and the relative photoluminescence quantum yields of the Cu-In-Zn-Se-S NCs can be tuned by varying the Cu contents, the amount of Se powder, as well as the DDT dosage. In addition, the formation process of the multinary Cu-In-Zn-Se-S NCs is different from that of quaternary Cu-In-Zn-S NCs, which is dominated by the doping of Cu ions into the In-deficient In-Zn-Se-S NCs but not the partial interdiffusion of Zn 2+ into the Cu-based NCs. This plausible deduction is based on the comparison of optical properties of the products synthesized using the hot-injection and one-pot methods. Furthermore, the performance of the solution-processed quantum-dot light-emitting diodes (QLEDs) using the Cu-In-Zn-Se-S NCs as emission layers is examined, and the QLEDs exhibit a high luminance over 1500 cd m −2 and a high peak current efficiency of ≈0.4 cd A −1 at 1000 cd m −2 .
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RSC Advances
·
2018
·Vol. 8
·期 61
·34877-34882
·
IF 2.936
Xue Han,Zhixin Qin,Mengyao Zhao,Jiajia Song,Fei Qu,Fengli Qu,Rong-Mei Kong
The illegal adulteration of melamine in dairy products for false protein content increase is a strong hazard to human health. Herein, a simple and sensitive colorimetric method was developed for the quantification of melamine in dairy products based on a Cu2+-hydrogen peroxide (H2O2)-3,3′,5,5′-tetramethylbenzidine (TMB) system. In this strategy, Cu2+ exhibits peroxidase-like activity and can catalyze the oxidation of TMB to oxidized TMB (oxTMB) in the presence of H2O2 with a blue colour change of the solution. However, the presence of melamine quickly interacts with H2O2 leading to the consumption of H2O2 and thus strongly hinders the oxidation of TMB. Under the optimal conditions, the absorbance change of oxTMB has a linear response to the concentration of melamine from 1 to 100 μM with a detection limit of 0.5 μM for melamine. The proposed method has many merits including more simplicity, good selectivity, and more cost-effectiveness without using any nanomaterials. The method was further successfully applied to detect melamine in dairy products including milk and infant formula powder.
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ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Xiao-Yan Xie,Xin-Yu Qian,Shi-Chao Qi,Ju-Kang Wu,Xiao-Qin Liu,Lin-Bing Sun
Metal–organic frameworks (MOFs) have drawn much attention for their highly promising applications, but the applications are often obstructed by the congenitally hydrothermal instability of the MOFs. Hybridizing the MOFs with other materials has been proved to be effective to solve the hydrothermal problems. Herein, a vapor-induced crystallization (VIC) method is employed for the first time to fabricate the hybrid MOFs based on the Cu-BTC and the natural clay attapulgite (NCA). Compared with the traditional solvothermal method for the hybridization, the VIC one has the obvious advantages of both reducing the solvent consumption and inducing the crystals self-repairing to generate perfect crystals of the hybrid MOFs. With an appropriate content of the NCA, the hybrid MOFs are proved to be highly stable even undergoing the hot water vapor (90 °C) for 12 h. The hybrid MOFs also exhibit the improved catalytic activity in catalyzing the styrene oxide ring-opening. The molar conversion of the styrene oxide over the hybrid MOF reaches 93.8% within 20 min, even higher than that of the unadulterated Cu-BTC (68.0%). These results indicate the promising application of the hybrid MOFs as the hydrothermal-stable and highly active heterogeneous catalysts.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Ge Ma,Junlin Lu,Qingguo Meng,Haiqin Lv,Lingling Shui,Yongguang Zhang,Mingliang Jin,Zhihong Chen,Mingzhe Yuan,Richard Nötzel,Xin Wang,Chuanyi Wang,Jun-Ming Liu,Guofu Zhou
In this work, a series of efficient visible-light-driven WO 3 /Cu (II) nanofiber photocatalysts, with superior photocatalytic activities for the degradation of dyes and aniline, were prepared by electrospinning and impregnation methods. The impregnation method brought about homogeneous distribution of Cu (II) species on the surface of WO 3 nanofibers. The prepared WO 3 /Cu (II) nanofiber photocatalysts exhibited enhanced visible-light absorption and reduced charge recombination, as compared to pure WO 3 nanofibers, due to the interfacial charge transfer (IFCT) effect between the Cu (II) species and WO 3 . The combined benefits of the grafting Cu (II) species on the surface of WO 3 , in terms of optical, surface, and texture properties, led to a significant improvement in the photocatalytic activity for the degradation of Rhodamine B (Rh B) and aniline under conditions of visible light irradiation. Upon the irradiation with visible light in the presence of WO 3 /Cu (II)-2% photocatalyst, the concentration of Rhodamine B (Rh B) decreased from 10 mg/L to 1.5 mg/L, and that of aniline solution decreased from 5 mg/L to 0.728 mg/L over a period of 3 h. And after running five cycles, the concentration of aniline solution could decrease from 5 mg/L to 0.89 mg/L by WO 3 /Cu (II)-2% photocatalyst.
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