RSC Advances
·
2020
·Vol. 11
·期 1
·48-56
·
IF 3.119
Yingjie Hu,Yuxin Mei,Baining Lin,Xuhong Du,Fan Xu,Huasheng Xie,Kang Wang,Yonghua Zhou
The one-pot synthesis of methyl isobutyl ketone (MIBK) and methyl isobutyl methanol (MIBC) from acetone and hydrogen is a typical cascade reaction comprised of aldol condensation-dehydration-hydrogenation. Pd loss and aggregation during long term operation are typical problems in industrial application. In this paper, an active and stable catalyst was achieved with defective UiO-66 as a support for Pd, which was synthesized with the ratio 15 : 1 of ZrOCl2·8H2O to ZrCl4 as Zr-precursors. The resultant Pd catalyst remained active for at least 1000 h with a MIBK + MIBC selectivity of 84.87–93.09% and acetone conversion of 45.26–53.22% in a continuous trickle-bed reactor. Besides the increased Brønsted acid amount generated by the defect sites was favorable for the activity, the cavity confinement in the UiO-66 (R = 15 : 1) structure also efficiently prevented Pd loss and aggregation during the long term run. The contrast of the characterization of the fresh and used Pd/UiO-66 (R = 15 : 1) indicated that the deactivation of the catalyst was attributed to carbonaceous accumulation on the catalyst surface, which could be easily regenerated by calcination. This work supplied a new alternative for the design and utilization of industrial catalysts for MIBK and MIBC synthesis.
研究领域:
催化化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Huiyi Zhang,Zeming Wang,Zhe Wang,Liang Wang,Yong Wang
Hydrogen peroxide (H2O2) is a worthy chemical substance with comprehensive applications, but its practical industrial methods involve complex and energy-consuming procedures. Electrocatalytic oxygen reduction for the production of H2O2 is a flexible alternative strategy, which requires a low-cost catalyst with high activity and selectivity for the 2e– ORR pathway. Here, we first present a straightforward and universal one-step hydrothermal method that directly combines Cr-ABIm with commercial carbon black (BP2000) to prepare H2O2 electrochemically with high selectivity and energy saving. A variety of characterization analyses display that the introduction of Cr-ABIm increases the number of defects and active sites and also enlarges the surface area of the catalyst for electrochemical reactions. Importantly, the valence state of Cr is changed (Cr3+ of Cr-ABIm converted to Cr5+) when Cr-ABIm anchors on BP2000, which accelerates the activity of the reduction reaction. The selectivity of the catalyst for H2O2 preparation is also determined by Koutecky–Levich analysis and rotating ring disk electrochemical tests. In a potential range of 0.2–0.7 V (vs reversible hydrogen electrode (RHE)), the electron transfer number of the Cr-ABIm@BP2000 catalyst is on the verge of 2.5, and the electrogenerated yield of H2O2 is 65%. In addition, its mass activity at 0.5 V is up to 7.56 A g–1. Density functional theory (DFT) calculations clarify that suitable N, O coordination on the active surface of BP2000s acquires the changing capacity of the valence state of Cr, thereby regulating the adsorption of intermediate products and endowing it with superior H2O2 performance. It is believed that Cr-ABIm@BP2000 will be a viable electrocatalyst for sustainable in situ generation of H2O2 from oxygen.
研究领域:
化学
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材料科学
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催化反应
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Yulong Gu,Wei Xu,Yinyong Sun
The development of active oxidative desulfurization (ODS) catalysts is of practical importance. Recently, MOF-808(Zr) has been attempted to use as ODS catalyst due to its various advantages. However, generally MOF-808(Zr) prepared by conventional method was less active in the oxidation reactions due to the lack of defect sites in the structure. In this contribution, we report that the catalytic oxidative performance of MOF-808(Zr) can be enhanced by acid treatment due to the formation of defect sites resulting from the partial removal of organic linkers in the structure. During the experiment, the effect of acid concentration, treatment time, the addition amount of oxidant and reaction parameters on the performance of MOF-808(Zr) was studied. The catalytic results show that MOF-808(Zr) treated with 0.4 M HCl for 1h can catalyze the oxidation of dibenzothiophene completely at 60°C in 15 min. The activity (mole number of converted DBT per hour per unit mass) is 70 mmol h −1 g −1 , which is much higher than that (45 mmol h −1 g −1 ) of parent MOF-808(Zr). In addition, the catalyst can be reused several times without obvious loss of catalytic performance.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2022
·Vol. 153
·期 3
·836-849
·
IF 2.936
Jiang Haoran,Xue Changhao,Sun Weijie,Gong Zhaoxiang,Yuan Xia
The esterification of cyclohexene with formic acid is the first step in synthesizing cyclohexanol via the indirect hydration of cyclohexene. In this work, we improved the efficiency of the esterification reaction by constructing a sulfonic-acid-functionalized UiO-66 solid-acid catalyst containing defect sites. By using acetic acid as the modulator, ZrCl 4 as the zirconium source, and 2-sulfoterephthalic acid monosodium salt as the ligand, a sulfonic-acid-functionalized UiO-66-SO 3 H with defect sites was prepared using a solvothermal synthesis method. Additionally, we also prepared UiO-66 with defect sites for comparison. We then investigated the regulation effects of acetic acid addition amount on the defect structures and acidity of the as-prepared materials. The results showed that the addition of acetic acid caused lattice defects in the as-prepared materials with a missing linker, and the specific surface area, pore volume, pore size, and particle size of the material changed significantly. The number of defect sites was determined by thermogravimetric analysis. Additionally, pyridine infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated that the ratio of Lewis acid to Brønsted acid sites, and the total acid content in the defect materials, greatly increased compared to pure UiO-66 and UiO-66-SO 3 H, which greatly enhanced the acid catalytic performance of the material. Among these, UiO-66-SO 3 H(20), which was prepared by adding 20 mL of acetic acid, exhibited the best catalytic activity. The conversion rate of cyclohexene reached 83.4%, the selectivity toward cyclohexyl formate was 99.8%, and the catalyst could be reused three times. Graphical Abstract The purpose of this work was to improve the efficiency of the esterification reaction of cyclohexene with formic acid by constructing a sulfonic acid-functionalized UiO-66 solid acid catalyst containing defective sites. The regulation effect due to the amount of acetic acid added on the defect structure and acidity of the as-prepared materials was investigated.
研究领域:
化学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Liqiang Ma,Pengpeng Wei,Jingfang Li,Xue Lu,Guangming Li
Aerobic oxidative desulfurization (AODS) is a promising deep desulfurization technique that can efficiently remove organosulfur compounds under mild conditions. In this study, a one-pot hydrothermal method was designed to encapsulate a quaternary heteropolyacid H 4 PVMo 4 W 7 O 40 (PVMo 4 W 7 ) into rht -MOF-1 { rht -MOF-1 = [Cu 6 O(TZI) 3 (H 2 O) 6 ] 4 ⋅nH 2 O}, and the single crystal structure of H 4 PVMo 4 W 7 O 40 @ rht -MOF-1 ( 1 ) indicated that PVMo 4 W 7 was effectively encapsulated within cage C of rht -MOF-1. Further, a similar one-pot hydrothermal reaction was employed to introduce acetic acid, resulting in the synthesis of defective H 4 PVMo 4 W 7 O 40 @ rht -MOF-1-De ( 1 - De ). 1 - De was characterized using various techniques such as FT-IR, XRD, TGA, XPS, and EPR. In comparison with 1, 1 - De exhibited numerous defect sites, high porosity, high surface area, high Mo 5+ ion content, well-dispersed PVMo 4 W 7 , and abundant oxygen vacancies, leading to efficient AODS capability. When applied as catalyst, 1 - De demonstrated high catalytic activity and good recyclability for the oxidation of dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) under air atmosphere. Strikingly, the removal rates of DBT and 4,6-DMDBT reached 99 % and 96 %, respectively under optimized conditions.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Xiaoyu Jiang,Xiang Li,Yumin Liu,Haifa Zhai,Gongke Wang
The preparation of ultrathin nanosheets is conducive to increasing the material's specific surface area and introducing suitable defect sites. This facilitates the enhancement of the separation efficiency of photogenerated charge carriers and improves the adsorption and degradation efficiency toward pollutants. Various nitrogen-rich precursors were employed for the synthesis of bulk g-C 3 N 4 (BCN) and its ultrathin nanosheets, with a focus on investigating their photocatalytic performance. The degree of polymerization of g-C 3 N 4 influenced its hydrogen bonding and C/N ratio, affecting the ultrathin nanosheet microstructure. Oxidation disrupted the tri- s -triazine rings in the ultrathin nanosheets of g-C 3 N 4 prepared via dicyandiamide. However, g-C 3 N 4 prepared from urea and melamine as precursors retained its primary characteristics after thermal oxidative exfoliation, attributed to interlayer hydrogen bonds, small lateral size at low polymerization degrees, and increased vacancy defects. In the photocatalytic degradation system, two-dimensional nanosheets of g-C 3 N 4 synthesized from urea exhibited the highest catalytic efficiency.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Xinzhe Shi,Rongrong Deng,Qibo Zhang
Co 3 O 4 -based electrode materials exhibit great potential for utilization as efficient catalysts for the oxygen evolution reaction (OER), especially in acidic media. However, enhancing their catalytic stability remains a crucial challenge. Herein, we present a facile electrochemical deposition approach coupled with calcination treatment to achieve in-situ growth of active Co 3 O 4 films from a deep eutectic solvent with water as the modifier. The incorporation of water optimizes the structure of fabricated Co 3 O 4 by increasing oxygen vacancies and elevating the Co 2+ /Co 3+ ratio, enabling it to sustain the OER in 0.5 M H 2 SO 4 . Impressively, the catalyst grown on Pt/Ti substrate exhibits stable operation over 125 h at 10 mA cm −2 . Attenuated total reflection-fourier transform infrared (ATR-FTIR) spectroscopy reveals that OER on the defect-rich Co 3 O 4 catalyst occurs through both lattice oxygen mediated mechanism (LOM) and adsorption evolution mechanism (AEM).
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2025
·
IF 14.9
Huan Ma,Xuntao Zhang,Mingxuan Tang,Zhenjiang Lu,Min Wang,Xinxin Yin,Jing Xie,Jindou Hu,Yali Cao
Sodium-ion batteries (SIBs) show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries (LIBs). However, the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion (Na + ) radius hinder the practical application of SIBs. Here, we successfully prepared SnS 2− x Se x nanodots embedded within N-doped carbon nanofibers (CNF) for use as electrode materials of SIBs. The introduction Se provided abundant anionic defect sites for sodium-ion storage and enlarged the interlayer spacing of SnS 2 . In addition, the ultrafine nanodot structure reduces the volume expansion of SnS 2− x Se x and shortens the ion transport path. As an anode of SIBs, SnS 2− x Se x /CNF demonstrates remarkable reversible capacity (719 mAh g −1 at 0.5 A g −1 ), along with rapid charging ability (completing a charge in just 127 s). Meanwhile, the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg −1 at a high-power output of 5526 W kg −1 . This study presents an effective strategy for fabricating high-performance sulphide-based anode materials for SIBs, offering broad prospects for application.
研究领域:
材料科学
·
电化学能源存储
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·
IF 3.5
Zhengyan Wang,Chenhao Yuan,Dong Yang,Mifen Cui,Jihai Tang,Zhuxiu Zhang,Xu Qiao
It is of great significance to develop catalysts for the degradation of hexachlorobenzene from the industrial thermal process. In this paper, formic acid was used as a modulator to generate defect sites in Ce/Zr-UiO-66 with intrinsic Brønsted acidity. The defective formate ligands were removed through methanol–water vapor treatment to expose additional open metal sites with Lewis acidity. The intrinsic Brønsted acid sites of the resulting Ce/Zr-UiO-66-FA-P achieved a hexachlorobenzene degradation efficiency of 99.5% at 250 °C. The generated Lewis acid sites facilitated the C–C cleavage of degradation intermediates. More than 95.0% of the final products were CO2/CO, coupled with chlorinated alkanes/alkenes, which outperformed other benchmark metal oxide catalysts. The Ce/Zr-UiO-66-FA-P catalyst maintained its catalytic activity in the model industrial flue gas and humid environment. The degradation pathway of hexachlorobenzene was tracked using in situ FT-IR spectra.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Chang Liu,Hongjie Zheng,Yuwei Wang,Nan Xiao,Kai Yu,Hui Li,Xu Zhang,Hongcun Bai,Tianyi Ma,Jieshan Qiu
Soft carbon has been regarded as one of the most promising anode materials for potassium-ion batteries. However, the rearrangement of planar aromatics at high carbonization temperature usually yields a highly graphitized structure, which generally leads to inferior rate and cycle performance. In addition, the role of intrinsic carbon defects on potassium storage has not been well reported yet. In this work, crosslinked pitch-based soft carbon nanosheets have been synthesized through the iodination/dehydroiodination process at low temperature and carbonization with NaCl template. The iodine-treatment efficiently crosslinks the planar aromatics to three-dimensional framework by alkyl-bridged linkages, and reduces the strong π-π interaction during carbonization. This unique microstructure yields an ordered-in-disordered carbon microstructure, enlarged interlayer spacing, and abundant intrinsic defect sites. Benefited from these merits, the optimal sample displays 140% increase of reversible capacity to the pristine pitch-based carbon at 5 A g −1 . Particularly, it also presents 87.4% capacity retention after 1000 cycles at 1 A g −1 . This facile but simple strategy is expected to expand to other high-performance carbon materials and further understand the effect of intrinsic defects for potassium storage and beyond.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2020
·
IF 4.825
Zhiyuan Liu,Jingpeng Niu,Weimin Long,Bing Cui,Kun Song,Fan Dong,Dong Xu
Indoor formaldehyde from substandard furniture and decorative materials seriously endangers human health. How to remove effectively indoor formaldehyde with low concentration at room temperature is a challenging problem. Using a MnO2/AlOOH composite by the MnO2 modification as a catalyst provides an effective approach to solve this challenge. Here, a new type of MnO2/AlOOH composite catalyst with high ability to remove indoor low-concentration formaldehyde was prepared by redox reaction at room temperature. A MnO2/AlOOH composite with a homogeneous dispersion of MnO2 has high specific surface area and a large amount of surface hydroxyl (−OH) which plays a major role in the adsorption of formaldehyde. A partially crystalline structure was observed in the composite, which contains multivalent Mn ions and a large number of vacancy defects. The surface −OH of composite shows strong oxidation activity through the charge exchange of multivalent Mn ions and vacancy defects. The composite has a higher ability to remove indoor low-concentration formaldehyde compared to the birnessite MnO2 at room temperature. This study proposes a new idea for the improvement of catalytic performance in the structure and composition of the catalyst.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 6
·4443-4457
·
IF 4.6
Junqi Zhang,Yongwang Li,Zhiwei Zhang,Zheng Wang,Jiaxing Zhang,Shuai Liu,Yang Qin,Bingxin Zhu,Tongxue Zhang,Hongyu Wang,Fumin Wang,Xubin Zhang
The development of simple, efficient and economical catalysts for the hydrogenation of biomass to produce high value-added chemicals is of great significance in solving the energy crisis. In this work, a series of non-precious metal catalysts (Cu–Al2O3–ZnO) with different defect sites were prepared by etching Devarda's alloy. Under optimized mild reaction conditions, the furfural conversion and furfuryl alcohol selectivity are both greater than 99.0%, and the catalyst has good reusability. Characterisation and experiments were used to investigate the activate species for hydrogenation reaction. It can be proved that the low-valent Cu species in the Cu–Al2O3–ZnO catalysts play an important role as adsorption and dissociation sites for H2. Different etching degrees and sample reduction temperatures of the alloy can be used to adjust the content of acidic sites such as Al2O3 and CuO, which have appropriate adsorption properties for furfural. ZnO promotes the dispersion of the Cu species and enhances the accessibility of the active sites. The etching method achieves the interaction between species to further enhance the stability and activity of the catalyst. The catalytic performance of the catalyst is very competitive and this study provides a new method for the efficient hydrogenation of furfural to furfuryl alcohol.
研究领域:
化学工程
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可再生能源
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催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）