Nanomaterials
·
2021
·Vol. 11
·期 9
·2177
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IF 5.076
Easar Alam,Qiyan Feng,Hong Yang,Jiaxi Fan,Sameena Mumtaz,Farida Begum
In this study, iron oxide (Fe3O4) was coated with ZrO2, and doped with three rare earth elements((Y/La/Ce), and a multi-staged rare earth doped zirconia adsorbent was prepared by using uniform design U14, Response Surface methodology, and orthogonal design, to remove As3+and As5+from the aqueous solution. Based on the results of TEM, EDS, XRD, FTIR, and N2-adsorption desorption test, the best molar ratio of Fe3O4:TMAOH:Zirconium butoxide:Y:La:Ce was selected as 1:12:11:1:0.02:0.08. The specific surface area and porosity was 263 m2/g, and 0.156 cm3/g, respectively. The isothermal curves and fitting equation parameters show that Langmuir model, and Redlich Peterson model fitted well. As per calculations of the Langmuir model, the highest adsorption capacities for As3+and As5+ions were recorded as 68.33 mg/g, 84.23 mg/g, respectively. The fitting curves and equations of the kinetic models favors the quasi second order kinetic model. Material regeneration was very effective, and even in the last cycle the regeneration capacities of both As3+and As5+were 75.15%, and 77.59%, respectively. Adsorption and regeneration results suggest that adsorbent has easy synthesis method, and reusable, so it can be used as a potential adsorbent for the removal of arsenic from aqueous solution.Keywords:magnetic Fe3O4;uniform design;surface response methodology;multi-staged doping;arsenic (III & V) removal
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Weiyuan Yao,Yue Liu,Zhongbiao Wu
A series of CeO 2 @Ce-O-P “multi-core@shell” catalysts were synthesized in this paper for selective catalytic reduction (SCR) of NO with NH 3 . The experimental results had showed that CeO 2 @Ce-O-P-30:3 yielded best SO 2 tolerance of an over 70% deNO x efficiency at 250 °C in the presence of 100 ppm SO 2 for 20 h, which was much higher compared to pure Ce-O-P and CeO 2 samples. Further characterization results indicated that Ce-O-P coating layer could somewhat inhibit sulfur depositing on the catalysts during SCR reaction in the presence of SO 2 , thereby protecting the active sites from SO 2 poisoning. Especially, O 2 -TPD results illustrated that a great amount of active oxygen species were retained on used CeO 2 @Ce-O-P catalyst after a long term reaction. The synergetic effect of “multi-core@shell” structure could be attributed to such enhanced performances. The “core” CeO 2 devoted abundant active oxygen sites to fulfill the SCR reaction. And the “shell” Ce-O-P could not only provide acid sites, but also protect the active oxygen species by avoiding the over-adsorption of SO 2 on the catalyst. This work could provide a new way to increase the sulfur resistance for low temperature SCR catalysts.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Qin Wu,Chi Fan,Ya Wang,Xiaoping Chen,Guimin Wang,Zhengxing Qin,Svetlana Mintova,Junhua Li,Jianjun Chen
The reduction of NO x emission during the cold start period of diesel vehicles requires special attention in accordance with the emission regulations. In this work, the direct incorporation of cerium and copper in SAPO-18 catalyst with AEI type framework structure (CuCe-SAPO-18) resulting in a substantial enhancement of the performance in the low-temperature NH 3 -SCR reaction (<200 ℃). A small amount of cerium (0.13–0.31 wt%) broadened the reaction temperature range of use and increased the hydrothermal stability of the catalyst considerably. The cerium species was introduced in the ion-exchange sites of Cu-SAPO-18 in the form of Ce 3+ ions even with high loading (3.15 wt%). The Ce 3+ ions were found to affect the distribution of silicon and aluminum atom coordination ( 29 Si NMR, 27 Al MAS NMR) in the AEI-type skeleton structure leading to an increase of both the amount of active Cu 2+ species and the acidity of the CuCe-SAPO-18 catalysts that are beneficial for the NH 3 -SCR reaction.
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LANGMUIR
·
2025
·
IF 3.9
Shangpu Zhuang,Yilin Lei,Fan Xue,Tao Wei,Di Hao,Luming Qi,Lichun Nian,Yuyu Sun,Mifen Cui,Zhuxiu Zhang,Ruiping Wei,Jihai Tang,Xu Qiao
In heterogeneous catalysis research, a significant challenge is to elucidate how metallic copper (Cu0) and cuprous (Cu+) phases interact with their supporting materials, with a special emphasis on how oxygen vacancy (OV) sites participate in hydrogenation processes. In this work, Cu/CexZr10-x catalysts were prepared by introducing Zr-incorporated Ce-MOF, followed by copper impregnation and calcination. Characterization by TEM, XPS, EPR, H2-TPD, Py-IR spectroscopy, and in situ FTIR revealed that Zr doping enhanced the OV concentration, stabilized Cu+ species, and generated abundant Lewis acid sites. The optimal Zr content effectively balances the Cu0/Cu+ redox couples and acid sites, accelerating desired reactions, while excessive Zr incorporation leads to increased Brønsted acidity and promotes undesirable side reactions. These features synergistically enhance the adsorption of 5-HMF, activate carbonyl groups, and facilitate the sequential hydrogenation and deoxygenation processes, thereby achieving 5-HMF fully converted and achieving a 2,5-DMF selectivity of 98.2% under optimal reaction parameters. This study clarifies the cooperative mechanism among Cu active sites, OV, and acid sites in the conversion of 5-HMF and demonstrates that rational Zr incorporation in MOF-derived Cu/CexZr10-x catalysts can precisely modulate surface properties and significantly improve catalytic performance. These findings offer valuable guidance for the rational design of advanced heterogeneous catalysts aimed at biomass valorization and the production of renewable fuel.
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CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Jin Wang,Junxia Wang,Yibing Zhang,Yuxiang Li,Yuancheng Teng,Zhe Wang,Hongbin Tan
A series of Nd and Ce co-doped (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores were synthesized by flux method at 900–1000 °C using nitrates as starting materials and a small amount of NaF as fluxing agent . The influences of contents of Nd/Ce, fluxing agent and reaction temperature on the phase structure of the pyrochlores were systematically investigated by X-ray diffraction (XRD) and Raman spectroscopy (Raman). The chemical stability of Nd and Ce co-doped pyrochlore bulk ceramics was also evaluated. XRD and Raman results showed that the crystalline phase of (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores always remained a single disordered defect-fluorite structure for any x value. XRD, Raman spectrum and SEM-EDX results revealed that the Nd and Ce could be co-doped at the Gd-site and Zr-site of the Gd 2 Zr 2 O 7 pyrochlore structure, respectively. The normalized release rates of Gd, Zr, Nd and Ce in (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 pyrochlore bulk ceramics (x = 0.25, 0.5 and 0.75) remained relatively constant in a low value below 10 −4 g m −2 d −1 at 90 °C for 7 days, exhibiting superior chemical stability.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Junli Nie,Gangqiang Zhu,Weibin Zhang,Jianzhi Gao,Peng Zhong,Xiaotao Xie,Yu Huang,Mirabbos Hojamberdiev
Flower-like n -type CeO 2-δ is hybridized with p -type β-Bi 2 O 3 nanoparticles to design a novel β-Bi 2 O 3 /CeO 2-δ p - n heterojunction photocatalyst via a thermal treatment process of Bi/Ce(CO 3 )(OH) precursor. The synthesized β-Bi 2 O 3 /CeO 2-δ exhibits a remarkable enhancement in NO removal and significant suppression of toxic intermediates nitrogen dioxide (NO 2 ) under visible light irradiation. The superior photocatalytic activity of β-Bi 2 O 3 /CeO 2-δ for NO removal is mainly derived from the synergistic effects of the oxygen vacancies (OVs) and p-n heterojunction. The OVs not only enhance the visible light utilization and boost the separation of electron-hole pairs but also improve the adsorption and activation of NO and O 2 . Particularly, the p-n heterojunction is beneficial for the interfacial migration of photogenerated charge carriers. Electron spin resonance (ESR) and trapping experiment reveal that the synergistic effects of OVs and p-n heterojunction can induce the generation of more active species. The electrochemical measurements and density-functional theory (DFT) calculations in-depth confirm that both p-n heterojunction and OVs can accelerate the interfacial charge transfer, resulting in the deep oxidation of reactants. Therefore, the flower-like β-Bi 2 O 3 /CeO 2-δ p-n heterojunction photocatalyst exhibits an advanced photocatalytic activity for deep NO removal and a suppressed NO 2 generation. In addition, monitoring the reaction products by in situ Fourier transform infrared spectrum (FTIR) further validates that the main products of nitrates are formed during the photocatalytic process. This work demonstrates a straightforward approach for construction of p-n heterojunction photocatalysts, which can enhance the effective photocatalytic activity and stability for NO removal.
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DESALINATION
·
2025
·
IF 9.8
Xinyu Yang,Hao Jiang,Zongsheng Hu,Fanju Meng,Bing Hou,Nan Li,Jingwen Pan,Lei Wang
Excessive fluoride (F − ) in water environment seriously endangers ecological security. This study constructed a series of dual-metal loaded biochar adsorbents (CeFe@BC) by modifying cerium-based materials through Fe doping and coupling with straw-derived biochar substrates. Ce 9 Fe 1 @BC 11 exhibited a remarkable F − adsorption capacity of 110.32 mg/g and had broad operational pH range (q e(pH=2 – 12) ≥ 82.61 mg/g). It showed exceptional selectivity and affinity toward F − even in multicomponent systems. The adsorption process was successfully characterized by pseudo-second-order kinetic (R 2 ≥ 0.999) and Temkin isotherm model (R 2 ≥ 0.952), indicating a chemisorption-dominated mechanism. Mechanistic studies revealed that Fe(II) doping maintained the quantity of Ce(III) active adsorption sites through the Fe(II)/Ce(IV) redox reactions, enabling the inverse transformation from Ce(IV) to Ce(III), rather than participating directly in adsorption. This regeneration mechanism increased the number of adsorption active sites of the material by re-reducing Ce(IV) back to Ce(III) during fluoride adsorption or desorption, thereby significantly enhancing adsorption performance. Unlike other anions that adsorb solely via substitution of terminal hydroxyl groups (T-OH) on metal oxides, fluoride onto CeFe@BC exhibited a dual-site adsorption behavior, involving both T-OH substitution and occupancy of bridging hydroxyl (B-OH) sites. Consequently, the T-OH and B-OH groups coordinated with Ce(III) constitute the primary active adsorption sites. The hierarchical porous structure of the straw biochar exposed abundant adsorption sites and also enhanced electron transfer during redox cycles due to its superior conductivity, enabling regeneration of Ce(III) active sites. This work provided a novel strategy for the synergistic structural-functional modulation of high-performance fluoride adsorbents, advancing the rational design of materials for environmental remediation.
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SYNTHESIS-STUTTGART
·
2019
·Vol. 51
·期 17
·3221-3230
·
IF 2.867
Wei Sun,Mingjuan Zhang,Peilang Li,Yiqun Li
A novel and highly efficient one-pot synthesis of polysubstituted imidazoles from α-hydroxyphenylacetic acids, diphenylacetylene, and amines has been achieved by Pd(OAc)2/Ce(SO4)2/Bi(NO3)3 trimetallic catalytic system. A series of control experiments showed that this overall reaction occurs through a one-pot cascade process combining the steps of decarboxylation of α-hydroxyphenylacetic acids, Wacker-type oxidation of diphenylacetylene, and Debus–Radziszewski annulation of aryl aldehydes and benzil generated in situ, as well as amines. This reaction represents a novel multicomponent reaction using α-hydroxyphenylacetic acids and diphenylacetylene as sources of aryl aldehydes and a β-diketone. This process exhibits a broad substrate scope and a good functional group tolerance to assemble the corresponding polysubstituted imidazoles in excellent yields (72–88%) under mild conditions.
研究领域:
有机化学
·
催化化学
·
药物化学
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合成方法学
·
杂环化学
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Wei Wen,Xiaoqiang Du,Xiaoshuang Zhang
Replacing fossil fuels by electrocatalytic water splitting for producing hydrogen and oxygen is one of the most promising ways to solve the energy crisis and environmental pollution. In this work, a series of M doped N-Ni 3 S 2 (M = Cu, Fe, Co and Ce) material was firstly synthesized and in situ grown on nickel foam substrate by a typical two-step hydrothermal synthesis method. Two probe reactions, water oxidation and urea oxidation, were selected to investigate the catalytic performance of these materials. What is noteworthy is that the Fe doped N-Ni 3 S 2 material exhibits superior water oxidation properties with requiring only 270 mV of overpotentials to drive current densities of 100 mA cm −2 , which is one of the best activities reported so far. After a long time of durability measurement, the current density of the Fe doped N-Ni 3 S 2 material will be attenuated, suggesting that the surface of the material will be in situ oxidized to oxide or hydroxide, which is the true active species. For urea oxidation, the Co doped N-Ni 3 S 2 material shows superior catalytic performance with requiring only 1.36 V potentials to drive 100 mA cm −2 current densities. Density functional theory (DFT) calculation shows that different adsorption energy of water for N-Ni 3 S 2 , N-Cu-Ni 3 S 2 , N-Fe-Ni 3 S 2 and N-Co-Ni 3 S 2 leads to the different catalytic activity. Experimental results demonstrate that the improved catalytic performance is assigned to faster electron transfer rates, exposure of abundant active center and better conductivity due to N and cation doping. This work provides new lessons for doping engineering for water splitting reactions.
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DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 47
·17774-17784
·
IF 4.39
Fangfang Wang,Zihao Liu,Kuanjian Zhang,Qingqing Zha,Yonghong Ni
Developing active, durable, and inexpensive electrocatalysts for the oxygen evolution reaction (OER) is drawing increased interest. Here, a mild hydrothermal–electrodeposition two-step route is designed for the preparation of Ce-doped Ni–S@NiMoO4 micropillar composites on nickel foam (CeNiS@NiMoO4/NF). The as-constructed CeNiS@NiMoO4/NF electrode shows an ultralow overpotential, fast kinetics, superb intrinsic activity and excellent long-term stability for the OER. In 1 M KOH solution, 187 mV overpotential is required to deliver a current density of 10 mA cm−2 with a Tafel slope of 35.28 mV dec−1, and in a saline-alkaline solution of 1 M KOH and 0.5 M NaCl, only 260 mV overpotential is needed to reach 100 mA cm−2, demonstrating its excellent OER performance. The above outstanding electrocatalytic activity is attributed to the influence of CeNiS nanosheets on the surface microstructure of NiMoO4 micropillars, which not only improves the conductivity of the catalyst, but also increases the surface area, as well as accelerates the escape of gases produced. Compared with other non-precious metal OER electrocatalysts, the as-prepared CeNiS@NiMoO4/NF presents stronger or close electrocatalytic activity and better durability, which provides a new electrocatalyst selection in practical applications.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 13
·5822-5828
·
IF 3.591
Yingwu Wang,Qiang Lin,Ping Ning,Chi Wang,Heping Zeng,Xin Sun,Xin Song,Kai Li
H2S and PH3, which are ore-thermal furnace gases, are harmful to humans and the environment. Here, the performance of a catalyst, Ce–Cu–Al trimetallic composite catalyst, is further explored by examining the influence of the used acid. The effects of acids on the structural features, surface functional groups, and activity of the catalysts were examined. Test results showed that the catalyst fabricated using 71.7 mmol nitric acid performed the best, and its capacity reached 229.8 mg g−1 (H2S) and 201.9 mg g−1 (PH3). Besides, SEM and TEM showed that the whole structure of catalysts was sharply changed by the species of the acid used, which was caused by the different combinations of components in the catalyst system. Because of the change in the catalyst structure, their physical and chemical properties are also adjusted. Using nitric acid could endow the catalyst with better properties, such as the best specific surface area, higher total pore volume, the strongest acid center, and the best reducing power. Combining the analysis results of FTIR spectroscopy, it was found that the detailed functional groups of NH2− and νON played a role in the reaction.
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Catalysis Science & Technology
·
2024
·
IF 4.4
Zhicheng Xu,Jin Xiong,Yuran Li,Junxiang Guo,Bin Wang,Tingyu Zhu
For industrial flue gas purification at medium and low temperatures, it is highly necessary to promote the denitrification activity of V-based catalysts in a SO2 atmosphere. Transition metals (Ce, Co, Fe, and Mn) are used to modify V/Ti catalysts to improve SO2 resistance with ammonium bisulfate deposition on the catalysts. Sulfation on Ce with less ammonium bisulfate deposition considerably improves the SO2 resistance of V1Ce5/Ti, and stable sulfation on TiO2 promoted by Co provides additional Brønsted acid sites for V1Co5/Ti to reduce the deactivation. Serious sulfation on V1Mn5/Ti with large ammonium bisulfate deposition on V1Fe5/Ti causes deeper deactivation. The formation mechanism of ammonium bisulfate on active metal sites and TiO2 carriers has been clarified. SO2 is adsorbed on V sites and transition metal sites followed by oxidation and ammoniation or adsorbed on TiO2 carriers followed by ammoniation and oxidation. The first pathway is more dominant than the second pathway in the presence of O2 with the co-oxidation of SO2 by O2 and lattice oxygen. The initial formation temperature and stable temperature of dominant intermediates were determined by in situ DRIFTS. SO2 adsorbed on TiO2 carriers is oxidized by V sites above 170 °C to form a tridentate sulfate, while SO2 adsorbed on transition metal sites is initially oxidized by transition metal sites above 50 °C to form monodentate and bidentate sulfates, as well as competitively oxidized by V sites above 170 °C to form tridentate sulfates. The selective adsorption of SO2 on transition metal sites or TiO2 carriers and the competitive oxidation of SO2 by transition metal sites and V sites provide a synergistic effect between V sites and transition metal sites to reduce ammonium sulfate deposition and release more active sites. These findings provide theoretical guidance to design and prepare V-based catalysts with high denitrification activity in the presence of SO2.
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