PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 22
·15547-15554
·
IF 3.3
Changyin Zhong,Yifei Yang,Yun Fang,Jun Chen,Bomin Feng,Hongbing Wang,Wenhua Luo,Yunxi Yao
Lanthanum oxide (La2O3) possesses superior reactivity during catalytic hydrogenation, but the intrinsic activity of La2O3 toward H2 adsorption and activation remains unclear. In the present work, we fundamentally investigated hydrogen interaction with Ni-modified La2O3. Hydrogen temperature programmed desorption (H2-TPD) on Ni/La2O3 shows enhanced hydrogen adsorption with a new hydrogen desorption peak at a higher temperature position compared to that on the metallic Ni surfaces. By systematically exploring the desorption experiments, the enhanced H2 adsorption on Ni/La2O3 is due to the oxygen vacancies formed at the metal–oxide interfaces. Hydrogen atoms transfer from Ni surfaces to the oxygen vacancies to form lanthanum oxyhydride species (H–La–O) at the metal–oxide interfaces. The adsorbed hydrogen at the metal–oxide interfaces of Ni/La2O3 results in improved catalytic reactivity in CO2 methanation. Furthermore, the enhanced hydrogen adsorption on the interfacial oxygen vacancies is ubiquitous for La2O3-supported Fe, Co, and Ni nanoparticles. Benefiting from the modification effect of the supported transition metal nanoparticles, the surface oxyhydride species can be formed on La2O3 surfaces, which resembles the recently reported oxyhydride observed on the reducible CeO2 surfaces with abundant surface oxygen vacancies. These findings strengthen our understanding of the surface chemistry of La2O3 and shed new light on the design of highly efficient La2O3-based catalysts with metal–oxide interfaces.
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CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Haiyan He,Ping Yang,Jia Li,Ruixia Shi,Ling Chen,Aiyu Zhang,Yuanna Zhu
CeO 2 nanostructures with various morphologies were prepared through controlling preparation conditions via a hydrothermal method without any surfactants and templates. Cerium acetate, cerium chloride and cerium nitrate were used as cerium precursors to investigate the influence of anions on the growth process of CeO 2 nanostructures. The morphology evolution of CeO 2 and Ce(OH) 3 nanostructures indicates that the anions play an important role for the growth kinetics of resulting samples. Cl − and Ac − ions promoted the formation of one dementional (1D) CeO 2 nanostructures such as nanowires, nanorods and nano hexagonal prisms, while the oxidizing anion NO 3 - facilitated the synthesis of CeO 2 nanocubes. The hydrothermal reaction temperature is another key to govern the morphologies of CeO 2 nanostructures. The formation process of the nanostructures was explored and the possible growth mechanism was discussed. The variety of CeO 2 nanostructures represented inequable catalytic performance for CO oxidation . Because of different surface areas and structures, CeO 2 nanowires revealed the best catalysis performance while that of the nanocubes is the worst.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2011
·Vol. 212
·期 23
·2589-2593
·
IF 2.437
Hongjun Yang,Manqing Yan,Stergios Pispas,Guangzhao Zhang
Poly[(ethylene carbonate)- co -(ethylene oxide)] is synthesized by ROP of 1,3-dioxolan-2-one using 1- tert -butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ5,Λ5-catenadiphosphazene as the catalyst. NMR spectroscopy shows that the copolymer chain consists of EO-EC-EO-EO sequences. GPC measurements indicate a PDI of 1.43–1.66 and show that the molecular weight increases with monomer conversion. Thermal analysis demonstrates that the copolymer is amorphous with a glass transition temperature of about –42 °C and an onset decomposition temperature of about 200 °C.
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ACS Applied Nano Materials
·
2021
·
IF 5.097
Zhongwen Dong,Chuanyu Yang,Dongpu Zhao,Yanan Wang,Weifeng Chu,Zhaochi Feng,Xiangxue Zhu,Wenjie Xin,Yongchen Shang,Shenglin Liu,Longya Xu
The interzeolite transformation approach has been used extensively for the quick synthesis of zeolites at a lower cost. Herein, an interzeolite transformation method for the quick synthesis of co-crystalline ZSM-5/ZSM-11 (CDM-5) nanoaggregates has been developed by precisely controlling the synthesis parameters and using 1,6-hexamethylenediamine as an organic structure-directing agent. In contrast, the irregular CDM-5 zeolite block obtained from an amorphous aluminosilicate gel takes a longer crystallization time using the conventional method. Combined with the related results of characterization, UV-Raman spectra show that double 6-membered rings in the parent USY zeolite framework are broken, and an ordered aluminosilicate aggregate species (OAAS) containing 4-membered rings (4Rs) are formed during the interzeolite transformation. HRTEM and SEM images demonstrate that the block OAAS is dissolved into amorphous nanoparticles, followed by converting into CDM-5 nanoaggregates. These results reveal that an OAAS is essential for the synthesis of CDM-5 nanoaggregates via the interzeolite transformation method. In addition, the CDM-5 nanoaggregate catalyst exhibits superior stability and resistance to carbon deposition in the alkylation reaction of benzene with ethanol compared with the irregular block CDM-5 catalyst.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Xueyun Liu,Cuimei Cheng,Na Zeng,Xiaoman Li,Qing Jiao,Changgui Lin,Shixun Dai
In comparison to narrow-band upconversion (UC) luminescence from lanthanide-doped systems, broadband UC emission enables a broad and tailorable emissive color, which is desirable for tunable lasers and multicolor display applications. Herein, dual continuous broadband UC emission covering the visible spectral region at 480–720 nm has been achieved for the first time in Yb 3+ /Mn 2+ co-doped glass ceramics (GCs) functionalized with the precipitation of dual-phase γ -Ga 2 O 3 / β -YF 3 nanocrystals . A tunable UC emissive color from yellowish to orange could be obtained under 980 nm excitation by varying the Mn 2+ doping content and heat treatment temperature of GCs. We ascribe this phenomenon to the typical transition of exchange-coupled Yb 3+ -Mn 2+ dimers in tetrahedral and octahedral ligand environments. The Stokes and power-dependent UC luminescence properties, fluorescence lifetimes, site occupation and the involved UC mechanism are discussed in detail. This research contributes to a better understanding of the UC process between Yb 3+ and Mn 2+ in transparent hosts and provides a novel perspective for designing broadband-emitting UC materials.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 36
·e55915
·
IF 2.7
Tianyuan Liu,Weihao Wang,Tian Yin,Zhikui Jiang,Zhichao Zhen,Guochun Yan,Junhui Ji
The application and promotion of biodegradable plastics are hindered by the imbalance between their mechanical and degradation performance imbalance, as well as high costs. Herein, a series of poly(ethylene adipate-co-terephthalate) (PEAT) copolyesters with excellent mechanical and degradation properties are synthesized by one-step melt polycondensation. The influence of the proportion of aliphatic groups in the molecular chain on the structure and properties, especially the degradation performance, of the copolyesters was studied. The molecular chain flexibility and degradability of PEAT increases with increasing of adipic acid content and decreasing of ET fragment length ( L ET ). The comprehensive mechanical properties of PEAT60 can be comparable to traditional packaging material poly(butylene adipateco-terephthalate) (PBAT). The degradation performance of PEAT can be adjusted the molecular chain structure. PEAT with L ET < 3 exhibit degradation performance, and PEAT with L ET < 2.2 exhibit significant degradation acceleration. The excellent mechanical and degradable properties of PEAT copolyester make it expected to be used in degradable packaging and other fields to help solve plastic pollution, while its lower cost will aid in the promotion of degradable materials.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Qinbo Jiang,Zijuan Yu,Zong Meng
Edible double network oleogels were prepared by hydroxypropyl methylcellulose (HPMC) and glyceryl monostearate (GMS) by the cryogel-templated method. Hot GMS soybean oil solutions were absorbed by HPMC cryogels, which were further homogenized and cooled to form oleogels containing both the HPMC network and GMS network. The crystal network constructed by GMS crystal clusters significantly enhanced the mechanical and rheological attributes of oleogels. Both the HPMC network and the GMS network were built up due to hydrogen bonds. According to the normalization analysis of FTIR and the deepening of the shift of the absorption peak, hydrogen bonds could also be formed between HPMC and GMS to connect the two independent networks. Double network oleogels were further used to fabricate cookies and cakes, assessed by the texture profile analysis. The combination of the HPMC network and GMS network in preparing oleogels will promote the application of oleogels as the fat replacer .
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Nanomaterials
·
2022
·Vol. 12
·期 16
·2839
·
IF 5.719
Yuruo Zheng,Ghulam Hussain,Shuyi Li,Shanta Batool,Xiawa Wang
In this work, nanoparticles of Co1−xRexFe2O4and CoFe2−xRexO4(0 ≤ x ≤ 0.05) were synthesized by the sol-gel method. The Rietveld refinement analysis of XRD and Raman data revealed that all of the prepared samples were single phase with a cubic spinel-type structure. With the substitution of Re, the lattice parameters were slightly increased, and Raman spectra peak positions corresponding to the movement of the tetrahedral sublattice shifted to a higher energy position. Furthermore, Raman spectra showed the splitting of T2gmode into branches, indicating the presence of different cations at crystallographic A- and B-sites. The SEM micrograph confirms that surface Re exchange changes the coordination environment of metals and induces Fe-site structure distortion, thereby revealing more active sites for reactions and indicating the bulk sample’s porous and agglomerated morphology. The vibrating sample magnetometer (VSM) results demonstrated that the synthesized nanoparticles of all samples were ferromagnetic across the entire temperature range of 300–4 K. The estimated magnetic parameters, such as the saturation magnetization, remanent magnetization, coercivity, blocking temperature (TB), and magnetic anisotropy, were found to reduce for the Co-site doping with the increasing doping ratio of Re, while in the Fe site, they enhanced with the increasing doping ratio. The ZFC-FC magnetization curve revealed the presence of spin-glass-like behavior due to the strong dipole–dipole interactions in these ferrite nanoparticles over the whole temperature range. Finally, the dielectric constant (εr′) and dielectric loss (tanδ) were sharply enhanced at low frequencies, while the AC conductivity increased at high frequencies. The sharp increases at high temperatures are explained by enhancing the barrier for charge mobility at grain boundaries, suggesting that samples were highly resistive. Interestingly, these parameters (εr′,tanδ) were found to be higher for the Fe-site doping with the increasing Re doping ratio compared with the Co site.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Yanyan Duan,Gen Zhao,Xiaotao Liu,Jiale Ma,Shuyao Chen,Yanlin Song,Xiaodong Pi,Xuegong Yu,Deren Yang,Yiqiang Zhang,Feng Guo
High power conversion efficiency (PCE) and good long-term stability are everlasting pursuit for perovskite solar cells. We present here CsPbBr 3 perovskite film deposited by vacuum co-evaporation of CsBr and PbBr 2 . By optimizing evaporation rate ratio of the two precursor and annealing temperature, perovskite films with large grain and high crystallinity are obtained. Furthermore, by regulating spinning speed of TiO 2 precursor solution and thickness of CsPbBr 3 film, a best PCE of 9.43% is recorded under 100 mW cm −2 illumination, providing a significant enhancement in contrast with 6.26% of device based on spin-coating method. Additionally, the PCE of resulting perovskite solar cell without encapsulation remains at 96% of initial value after storing for 480 h under humidity of 40% in air. Our findings in this work deliver an effective strategy to fabricate high-performance inorganic perovskite solar cells.
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Nuclear Materials and Energy
·
2021
·
IF 2.32
S. Krat,Yu. Gasparyan,Ya. Vasina,A. Prishvitsyn,G.De Temmerman,A. Pisarev
Available literature data for beryllium content in D-Be co-deposited layers was modeled using newly developed model. It was shown that the model adequately describes the experimental results. An empirical scaling for the available trap concentrations as a function of deuteron energy was introduced in order to improve the agreement between the experimental data and model predictions. The limited recombination rate describes the co-deposition better than the unlimited one. Assuming two types of traps in the film with detrapping energies of 0.8–0.9 and 1.2–1.3 eV and trap concentrations of 10 at. % and 1 at. %, respectively, and the deuterium implantation energy of 15.6 eV, the average relative deviation between experimental and predicted D/Be values of 1.9 was observed, which is better than the empirical D/Be scalings.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Jiami Ma,Weihong Guo,Cheng Ni,Xiaoping Chen,Weihao Li,Juan Zheng,Wei Chen,Zhu Luo,Jinlong Wang,Yanbing Guo
Ground-level ozone (O3) pollution has emerged as a significant concern due to its detrimental effects on human health and the ecosystem. Catalytic removal of O3 has proven to be the most efficient and cost-effective method. However, its practical application faces substantial challenges, particularly in relation to its effectiveness across the entire humidity range. Herein, we proposed a novel strategy termed “dual active sites” by employing graphitized carbon-loaded core–shell cobalt catalysts (Co@Co3O4-C). Co@Co3O4-C was synthesized via the pyrolysis of a Co-organic ligand as the precursor. By utilizing this approach, we achieved a nearly constant 100% working efficiency of the Co@Co3O4-C catalyst for catalyzing O3 decomposition across the entire humidity range. Physicochemical characterization coupled with density functional theory calculations elucidates that the presence of encapsulated metallic Co nanoparticles enhances the reactivity of the cobalt oxide capping layer. Additionally, the interface carbon atom, strongly influenced by adjacent metallic Co nuclei, functions as a secondary active site for the decomposition of O3 decomposition. The utilization of dual active sites effectively mitigates the competitive adsorption of H2O molecules, thus isolating them for adsorption in the cobalt oxide capping layer. This optimized configuration allows for the decomposition of O3 without interference from moisture. Furthermore, O3 decomposition monolithic catalysts were synthesized using a material extrusion-based three-dimensional (3D) printing technology, which demonstrated a low pressure drop and exceptional mechanical strength. This work provides a “dual active site” strategy for the O3 decomposition reaction, realizing O3 catalytic decomposition over the entire humidity range.
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PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 12
·16577-16588
·
IF 2.478
Zhang Dongke,Huang Ting,Zhao Pengfei,Zhang Ze,Qi Xingtao,Yang Zhenyu,Cai Jianxin
Due to the low conductivity of sulfur and the dissolution of polysulfides, the application of lithium–sulfur (Li–S) batteries have encountered certain resistance. Increasing conductivity and introducing polarity into the sulfur host can effectively overcome these long-standing problems. Herein, we first prepared Co 3 W 3 C@ C@CNTs/S material and used it in the cathode of lithium–sulfur batteries. Carbon nanotubes treated with acidification have good dispersibility in aqueous solution, good adsorption on positively charged metal ions due to abundant oxygen-containing functional groups on the surface. After carbonization treatment, Co 3 W 3 C will be firmly anchored on the surface of carbon nanotubes, which is conducive to improving the electrical conductivity and stability of its own materials. Polar Co 3 W 3 C can form a strong interaction with polysulfide intermediates, effectively inhibiting its shuttle effect, improving the utilization of sulfur cathode electrodes, and keeping the capacity and cycle stability. The Co 3 W 3 C@C@CNTs/S electrode material has a capacity of 1093 mA h g −1 at 0.1 A g −1 and 482 mA h g −1 at 5 A g −1 . Even after 500 cycles of 2 A g −1 , the capacity of each cycle is only reduced by 0.08%. The excellent stability of this material can provide a new idea for the future development of lithium–sulfur batteries.
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