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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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Jieqi Feng,Hao Lan,Qibin Tao,Wenqing Chen,Qizhou Dai
In this study, a novel NCNS-Ce-PbO 2 electrode was prepared by electrodeposition method using the rare earth metal Ce and synthesized nitrogen-doped carbon nanosheets (NCNSs). Various characterization and electrochemical performance tests showed that the NCNS-Ce-PbO 2 electrode possessed a denser surface and smaller grains than other NCNS-PbO 2 and Ce-PbO 2 electrodes, with more active surface sites and thus could generate more hydroxyl radicals. N , N -diethyl-m-toluamide (DEET) was selected as the model contaminant to evaluate the electrochemical performance of the novel NCNS-Ce-PbO 2 electrode. The effects of initial pollutant concentration, current density, electrolyte concentration, and initial pH on the removal rates of DEET and chemical oxygen demand (COD) were investigated. Under optimal conditions, after degradation of 150 min, the removal rate of DEET and COD reached 100% and 80.52%, respectively. GC–MS was used to identify intermediate products in the degradation process. The degradation mechanism and possible degradation pathways of DEET with NCNS-Ce-PbO 2 electrode were discussed. The good stability of the NCNS-Ce-PbO 2 anode was confirmed by accelerated lifetime experiments.
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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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PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Li-Yun Zhang,Jing-Pei Cao,Xue-Yu Ren,Xiao-Bo Feng,Jing-Xian Wang,Zi-Meng He,Tian-Long Liu,Zhen Yang,Xiao-Yan Zhao,Hong-Cun Bai
CeO2 receives extensive researches as an active component due to its providential catalytic center and favorable reducibility. Herein, a series of Ce-modified hierarchical ZSM-5 zeolites (FZ5) were prepared by HF (0.5 mol/L) etching followed by impregnation with different Ce loadings. The role of incorporating extra-framework Ce elements was assessed by catalytic upgrading of the cellulose pyrolysis volatiles to produce light aromatics (LAs). Introducing CeO2 could effectively regulate the acid properties of catalysts with an increase in Lewis acid sites and a decrease in Brönsted acid sites, which could significantly improve the catalytic performance. As a result, the selectivity toward LAs were significantly enhanced and the coke content dramatically decreased. The highest selectivity to LAs and the lowest coke content obtained over 1.0Ce-FZ5 zeolite (loading 1.0 wt % Ce) were 84.0% and 2.42 wt %, respectively. Additionally, the 1.0Ce-FZ5 catalyst exhibited excellent stability, maintaining nearly 90% carbon yield of LAs after the seventh regeneration test. CeO2 modification opened a simple and feasible way for promoting the LAs selectivity and catalyst stability during the reforming of biomass volatiles.
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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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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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PubMed
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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ENERGY
·
2024
·
IF 9
Tao Tan,Yushu Chen,Yongyue Wang,Zuhao Li,Zhige Zhang,Jun Xie,Yong Chen
The use of green biogas as a raw material for producing methanol-friendly syngas (H 2 /CO ≈ 2) for one-step methanol synthesis has gained significant attention. However, developing efficient catalysts with high activity and stability remains challenging, as they often face issues with stability and carbon deposition. This study presents a Ni/CeO 2 /HT catalyst designed for high activity and long-term stability by leveraging the Ce redox cycle and strong interactions between Ni-CeO 2 and hydrotalcite (HT). The catalyst benefits from abundant oxygen vacancies generated by the Ce 3+ - Ce 4+ pathway, enhancing its ability to activate CO 2 and H 2 O and providing excellent coke resistance. Comprehensive analyses of CO 2 /H 2 O adsorption and carbon elimination mechanisms were conducted using techniques such as in situ H 2 -TPR, CO 2 /H 2 O-TPSR, in situ CH 4 -TPSR, CO 2 /H 2 O-TPO, and FTIR. The Ni/CeO 2 /HT catalyst outperformed others in CO 2 /H 2 O adsorption and CH 4 activation capacity, promoting the generation of active oxygen species and effectively removing coke precursors, thereby improving resistance to Ni sintering and carbon deposition. At 750 °C and a weight hourly space velocity (WHSV) of 32,400 mLg Cat −1 h −1 , it achieved CH 4 and CO 2 conversions of 93 % and 66 %, respectively, with long-term stability exceeding 200 h.
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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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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Jingfang Tong,Weijie Lin,Ruixin Guo,Zhongzheng Deng,Haitao Zhou,Shu Guo,Xiaojun Kuang
Strong magnetic anisotropy in low-dimensional magnets leads to a significant rotating magnetocaloric effect, presenting new opportunities for the exploration of more efficient and streamlined refrigeration systems. In this study, we have successfully synthesized a series of centimeter-scale rare-earth-containing fluorocarbonates, K 4 RE 2 (CO 3 ) 3 F 4 ( RE = Ce, Pr, Nd, Sm, Eu, Tb, and Dy) through a supercritical hydrothermal method, featuring unique RE 2 O 12 F 4 magnetic dimers. The above materials' fundamental magnetism has been systematically investigated, and no long-range magnetic transitions were captured above 1.8 K. Based on the low-temperature specific heat results, the long-range magnetic ordering was found around 0.84 K and 0.97 K for K 4 Tb 2 (CO 3 ) 3 F 4 and K 4 Dy 2 (CO 3 ) 3 F 4 , respectively. Furthermore, the anisotropic magnetism of K 4 Tb 2 (CO 3 ) 3 F 4 and K 4 Dy 2 (CO 3 ) 3 F 4 reveals significant magneto-crystalline anisotropy, with the magnetic field ( B ) aligned along the RE 2 O 12 F 4 magnetic dimer, which acts as the easy magnetic axis. The maximum rotating field entropy change, − Δ S R max for K 4 Tb 2 (CO 3 ) 3 F 4 reaches approximately 9 J kg -1 K -1 around 17 K, while for K 4 Dy 2 (CO 3 ) 3 F 4 , it is approximately 5.5 J kg -1 K -1 near 11 K, both under a 7 T field applied along the c -axis. These findings highlight the potential of these compounds for magnetic refrigeration applications through a rotating crystallographic direction.
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