JOURNAL OF CATALYSIS
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2023
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IF 7.3
Yiwen Zou,Lin Dong,Siyang Yan,Jiaxu Liu,Lili Mu,Licheng Li,Yue Hu,Haifeng Qi,Shanjun Mao,Zupeng Chen
Efficient and selective N -alkylation of amines with alcohols via transfer hydrogenation is of great significance but extremely challenging. Here, we report the production of N –benzylaniline (BZA) from benzyl alcohol and aniline over various fine-shaped Ru/CeO 2 catalysts. The Ru/CeO 2 –R (rod) catalyst exhibits the highest catalytic activity among all catalysts, in which the yield of BZA reaches up to 88% with complete conversion, significantly higher than that of Ru/CeO 2 -C (cube, 52%) and Ru/CeO 2 -O (octahedron, 32%). Extensive experimental investigations disclose that Ru nanoparticles with a metallic state promote the dehydrogenation of the hydroxyl group and hydrogenation of imines, while the CeO 2 –R with rich oxygen vacancies facilitates the adsorption and activation of reactants. Furthermore, kinetic studies and time-resolved operando dual-beam Fourier transform infrared spectroscopy analysis confirms the transfer hydrogenation pathway, in which the benzyl alcohol is firstly dehydrogenated to benzaldehyde, followed by spontaneously reacting with aniline, and finally transforms into the N -benzylaniline rapidly.
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Journal of Materials Research and Technology-JMR&T
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2023
·
IF 6.4
Jing-feng Wang,Jun-qi Li,Lin-zhu Wang,Chao-yi Chen,Xiang Wang,Fei Zhao
The large primary carbides in H13 steel significantly affect its service life. In this study, pre-dispersion technology is used to disperse CeO 2 nanoparticles, which are then introduced into H13 steel. The effects of CeO 2 nanoparticles on the inclusions, primary carbides, microstructures, and properties of H13 steel are investigated. Ce-containing inclusions with size of 0.5–2 μm are generated and distributed uniformly in H13 steel owing to the reduction of CeO 2 by Al and C. Both the dendrite structure and primary carbides in H13 steel are refined by CeO 2 nanoparticles. The secondary dendrite arm spacing decreases from 13.51 ± 2.34 to 6.90 ± 1.23 μm. The size and number of primary carbides decrease from 1 to 5 to 1–3 μm, and from 1125 to 725/mm 2 , respectively. This is attributable to the disregistry of Ce-containing inclusions and primary carbides/austenite. The segregation of alloy elements in H13 steel is calculated using the Clyne–Kurz model. The properties of H13 steel are improved via the addition of CeO 2 ; in particular, its tensile strength, total elongation rate, and hardness are 726.38 MPa, 23.43%, and 243.49, respectively, which corresponds to increases by approximately 5.58%, 8.27%, and 10.11%, respectively. The results can facilitate improvements to the performance of H13 steel and the development of rare earth steel.
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NEW JOURNAL OF CHEMISTRY
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2023
·Vol. 47
·期 43
·19974-19982
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IF 3.3
Hao Fan,Qin Peng,Zhenxing Shen,Xuefeng He,Yiming Yang
Nitric oxide (NO), a major atmospheric pollutant and a precursor to haze, can be removed using the denitration catalyst. Mn and Ni are commonly used as denitration catalyst additives owing to their adsorption abilities for NO and ammonia (NH3). In this study, we synthesized Mn- and Ni-loaded Pt-modified sulfated cerium oxide (PtSCe) catalysts using an impregnation method and explored the effects of these elements. The results revealed that the two elements had contrasting effects on the denitration activity of the catalysts. Mn improved the water vapor and sulfur resistance of the PtSCe sample by increasing the concentration of weak acid sites, enhancing the redox ability, and increasing the content of surface-adsorbed oxygen. The elevation in oxygen vacancies, stimulated by the presence of Ce3+ and Mn3+, swiftly replenished the reactive oxygen species, thereby sustaining the high denitration efficiency of the MnPt/SCe sample. Active sites on the catalyst surface included NH3 adsorbed on Lewis acid sites, NH4+, and –NH2, along with bridging, monodentate, and bidentate nitrate groups. Regarding the catalyst reaction mechanism, we determined that the selective catalyst reduction of NH3-SCR over MnPt/SCe followed both the Eley–Rideal and Langmuir–Hinshelwood mechanisms. These findings offer crucial insights into the intricate relationship between metals, sulfates, and carrier molecules, thus providing implications for future catalyst design.
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MICROCHEMICAL JOURNAL
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2023
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IF 4.8
Yifei Li,Yucui Zhang,Huan Jiang,Mengyao Qi,Xia Zhang,Baowang Zhu,Lei Han
Although the fact that H 2 O 2 is employed in the medical, food, and chemical industries, trace detection of H 2 O 2 remains a difficult and significant problem. For the detection of H 2 O 2 residues, SERS assays based on enzyme inhibition techniques show promise. As a result, we csynthesized CeO 2 @nanogel/Au nanoparticles with dual enzyme-like capabilities to detect hydrogen peroxide in this study. CeO 2 nanozymes possess both peroxidase-like and oxidase-like activities which could oxidize colorless 3,3′,5,5′-tetramethylbenzidine to blue TMB oxide. Surprisingly, after the addition of nanogel, CeO 2 @nanogel were prepared and both of its dual enzymatic activities decreased, especially the oxidase-like enzymes almost disappeared. To better investigate the enzyme catalytic activity, Au NPs were introduced and CeO 2 @nanogel/Au nanozymes were self-assembly prepared. Based on the significantly enhancement of CeO 2 @nanogel/Au nanozymes peroxidase activity, we developed a Raman detection method for H 2 O 2 with TMB ox as the probe molecule. The Raman intensity showed good linearity for the concentration of H 2 O 2 in the range of 10 -9 M−10 −1 M with a correlation coefficient of R 2 = 0.9922 and a detection limit of 2.68 × 10 -12 M. Thus, the proposed SERS mode sensor exhibited good selectivity and interference resistance, providing a new avenue for environmental monitoring.
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CATALYSIS COMMUNICATIONS
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2023
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IF 3.7
Lirong Lv,Zhongguo Zhang,Sheng Wang,Yue Shan,Liangliang Wang,Tongzhou Xu,Peiran He
A series of Y Ce catalysts were prepared using Y-loaded (Y = Cu, Co, Mn) Ce-based metal–organic framework as a precursor. Mn-loaded CeO 2 exhibited significantly better catalytic activity in the catalytic oxidation of ethyl acetate (EA) than noble metal catalyst. The relationship between the physicochemical properties of Y Ce catalysts and catalytic activity was studied by different characterization methods. The enhanced catalytic activity was attributed to the strong interaction between the transition metals and Ce, high specific surface area, abundant lattice defects, more oxygen vacacies and higher O latt /(O latt + O ads + O w ) molar ratios. The main intermediates in the oxidation of EA were ethanol, acetic acid, acetone, acetaldehyde and diethyl ether.
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Crystals
·
2023
·Vol. 13
·期 6
·975
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IF 2.7
Yiwang Dong,Muhammad Yousaf,Muhammad Ali Kamran Yousaf Shah,Muhammad Akbar,Yuzheng Lu,Lei Zhang,Qadeer Akbar Sial,Peng Cao,Changhong Deng
Semiconductor ionic electrolytes, especially heterostructure composites, have a significant role in enhancing oxide ion conductivity and peak power density (PPD) because of their interfacial contact. In this work, the fluorite structure CeO2and spinel-based CoAl2O4samples, as a heterostructure composite electrolyte, are successfully fabricated. The p-type CoAl2O4and n-type CeO2heterostructure (CeO2-CoAl2O4) used as an electrolyte exhibits a cell performance of 758 mW/cm2under fuel cell H2/air conditions at 550 °C, which is quite higher than the pure CoAl2O4and CeO2fuel cell devices. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) verified the heterostructure formation including the morphological analysis of the prepared heterostructure composite. The heterostructure-based CeO2-CoAl2O4composite achieved a higher ionic conductivity of 0.13 S/cm at 550 °C temperature, which means that the constructed device successfully works as an electrolyte by suppressing electronic conductivity. Meanwhile, the obtained results demonstrate the semiconductor ionic heterostructure effect by adjusting the appropriate composition to build heterostructure of the n-type (CeO2) and p-type (CoAl2O4) components and built-in electric field. So, this work exhibits that the constructed device can be effective for energy conversion and storage devices.Keywords:semiconductor ionics;heterostructure;p-n junction;spinel;SOFCs
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Journal of Manufacturing Processes
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2023
·
IF 6.2
Yongchao Xu,Guangen Zhao,Qianting Wang,Youji Zhan,Bingsan Chen
Toxic and polluted ingredients are normally employed in the chemical mechanical polishing of sapphire wafers, which results in widespread environmental pollution. Thus, developing a novel green polishing technology is a significant challenge to achieve ultra-smooth and efficient polishing. In this study, novel CeO 2 coated diamond composite abrasives were used in the semi-fixed abrasive polishing of sapphire wafers, which were successfully synthesized by a modified precipitation approach without using explosive hazardous chemicals . During the whole polishing process, the polishing slurry only contains deionized water, without any other chemical reagents, to avoid environmental pollution. Polishing results showed that the surface roughness of sapphire polished by the composite abrasives was reduced to 6.1 nm, which was 26.5 % lower than that of pure diamond. Meanwhile, the material removal rate was 1.46 nm/min, with an improvement of 10.6 %, as well as a reduction in residual stress by approximately 29.8 %. Combined with the theory of micro-contact mechanics, the polishing mechanism and interfacial contact behavior of composite abrasives were investigated in depth through the analysis of polished sapphire surface and wear debris. The improvement of polishing performance may be attributed to the enhancement of solid-state reaction and its mutual balance with the mechanical removal action of composite abrasives.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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IF 8.6
Tongtong Xia,Zuliang Wu,Ehao Gao,Jiali Zhu,Shuiliang Yao,Jing Li
n -Undecane (C11) is a typical alkane pollutant, accounting for 6 % of the total volatile organic compounds (VOCs) emitted from the printing industry in China. A dielectric barrier discharge (DBD) reactor coupled with a catalyst of abundant oxygen vacancies prepared by Au nanoparticles 100 % loading on CeO 2 was developed for the plasma catalytic degradation of C11. Compared with CeO 2 , CeO 2 /γ-Al 2 O 3 , Au/γ-Al 2 O 3 , and Au/CeO 2 /γ-Al 2 O 3 , Au/CeO 2 exhibited significantly higher C11 oxidation performance with 98.8 % C11 conversion and 97.9 % COx selectivity. The strong interaction between nanosized Au and CeO 2 enhanced the ratios of Ce 3+ /(Ce 3+ +Ce 4+ ) and Au + /(Au + +Au 0 ), resulting in the formation of abundant oxygen vacancies with the highest band gap energy, which facilitated C11 oxidation. In addition, the reservation of reactive oxygen species generated by gas discharges on Au/CeO 2 catalyst synergistically promoted C11 complete oxidation, thus improving the oxidation stability within 600 min with stable C11 conversion and COx selectivity. This work presents an effective strategy to regulate the performance of catalysts for VOCs oxidation, and demonstrates that the plasma catalytic degradation of VOCs is feasible.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2023
·
IF 8.7
Chen Yang,Jian Yang,Shuangshuang Liu,Mingxue Zhao,Xu Duan,Hongli Wu,Lang Liu,Weizao Liu,Jiangling Li,Shan Ren,Qingcai Liu
Owing to its feasibility, efficiency in light-harvesting and effectiveness in the interfacial charge transfer between two n-type semiconductors, constructing heterojunction photocatalysts have been identified as an effective way for enhancing the photocatalytic properties. In this research, a C–O bridged CeO 2 /g-C 3 N 4 (cCN) Step-scheme (S-scheme) heterojunction photocatalyst was constructed successfully. Under visible light irradiation, the cCN heterojunction exhibited the photocatalytic degradation efficiency of methyl orange, which was about 4.5 and 1.5 times higher than that of pristine CeO 2 and CN, respectively. The DFT calculations, XPS and FTIR analyses demonstrated the formation of C–O linkages. And the calculations of work functions revealed the electrons would flow from g-C 3 N 4 to CeO 2 due to the difference in Fermi levels , resulting in the production of internal electric fields . Benefiting from the C–O bond and internal electric field, the photo-induced holes in the valence band of g-C 3 N 4 and the photo-induced electrons from conduction band of CeO 2 would be recombined when exposed to visible light irradiation, while leaving the electrons with higher redox potential in the conduction band of g-C 3 N 4 . This collaboration accelerated the separation and transfer rate of photo-generated electron-hole pairs, which promoted the generation of superoxide radical (•O 2 − ) and improved the photocatalytic activity .
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Shengjun Yi,Pincai Lai,Guilin Ma,Jinjian Pan,Zhen Chen,Yuanhang Qin,Xingmao Jiang
Nanocatalysis plays an important role in chemical industrial production, environmental protection and etc. However, traditional catalyst preparation methods are generally labor-intensive, time-consuming and need high-temperature calcination, which are not conducive to the preparation of nanostructured catalyst. Therefore, developing a green and facile method for nano-sized catalyst preparation is very significative. In this work, a series of nano-sized Co 3 O 4 /CeO 2 catalysts with high specific surface area, high oxygen storage and homogeneous distribution of active species were synthesized via a glucose-urea (G-U method), and applied in NO oxidation The NO oxidation performance indicates that the 12.5% CoCe G−U catalyst prepared by the G-U method shows higher activity than those of catalysts prepared by the traditional methods (precipitation, hydrothermal and impregnation methods). The characterization results revealed that the CoCe G−U catalysts have the highest specific surface area, pore volume, content of surface Ce 3+ and Co 3+ among the catalysts. Moreover, the nano Co 3 O 4 is better dispersed on CeO 2 , which resulted in more active oxygen species on the surface of the catalysts prepared by the G-U method. Herein, the higher specific surface area, the smaller Co 3 O 4 nanoparticles, the more active oxygen species and the higher Ce 3+ and Co 3+ contents of the CoCe G−U catalyst lead to the more excellent NO oxidation performance. This work provides a green and efficient approach for the industrial production of nano-sized oxide catalysts.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2023
·
IF 9.9
Xiaodong Hao,Xishuo Zhang,Yang Xu,Yuhao Zhou,Tingting Wei,Zhuangzhuang Hu,Lei Wu,Xinyi Feng,Jin Zhang,Yi Liu,Deqiang Yin,Shufang Ma,Bingshe Xu
To understand the underlying mechanism of the interfacial charge transfer and local chemical state variation in the nonprecious-based hydrogen evolution reaction (HER) electrocatalysts, a model system of the NiO/CeO 2 heterostructure was chosen for investigation using a combination of the advanced electron microscopic characterization and first-principles calculations. The results directly proved that interfacial charge transfer occurs from Ni to Ce, leading to reduction in the valence state of Ce and increased formation of V O . This would optimize ΔG H* and facilitate the hydrogen evolution process, resulting in outstanding HER performance in 1 M KOH with a low overpotential of 99 mV at the current density of 10 mA•cm −2 and a modest Tafel slope of 78.4 mV•dec −1 for the NiO/CeO 2 heterostructure sample. Therefore, the improved HER performance could be attributed to the synergistic coupling interactions and electron redistribution at the interface of NiO and CeO 2 . These results concretely demonstrate the direct determination of the interfacial structure of the heterostructure and provide atomistic insights to unravel the underlying mechanism of interfacial charge transfer induced HER performance improvement.
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BIOMATERIALS
·
2023
·
IF 14
Cai Feng,Zongling Xiong,Xianting Sun,Hao Zhou,Tianming Wang,Ying Wang,Harrison X. Bai,Peng Lei,Weihua Liao
It is a challenging task to develop a contrast agent that not only provides excellent image contrast but also protects impaired kidneys from oxidative-related stress during angiography. Clinically approved iodinated CT contrast media are associated with potential renal toxicity, making it necessary to develop a renoprotective contrast agent. Here, we develop a CeO 2 nanoparticles (NPs)-mediated three-in-one renoprotective imaging strategy, namely, i) renal clearable CeO 2 NPs serve as a one-stone-two-birds antioxidative contrast agent, ii) low contrast media dose, and iii) spectral CT, for in vivo CT angiography (CTA). Benefiting from the merits of advanced sensitivity of spectral CT and K-edge energy of Cerium (Ce, 40.4 keV), an improved image quality of in vivo CTA is successfully achieved with a 10 times reduction of contrast agent dosage. In parallel, the sizes of CeO 2 NPs and broad catalytic activities are suitable to be filtered via glomerulus thus directly alleviating the oxidative stress and the accompanying inflammatory injury of the kidney tubules. In addition, the low dosage of CeO 2 NPs reduces the hypoperfusion stress of renal tubules induced by concentrated contrast agents used in angiography. This three-in-one renoprotective imaging strategy helps prevent kidney injury from being worsened during the CTA examination.
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