Molecular Catalysis
·
2023
·
IF 4.6
Jie Huang,Wenhao Yang,Sen Zhang,Jingjie Luo,Changhai Liang
Catalytic hydrogenation of adiponitrile to hexamethylenediamine (HMDA) via alkali-free processes is essential to produce high-value downstream chemicals. In this work, we synthesized a series of Co@C CNT x catalysts using CNT promotion to strength the carbon skeleton derived by ZIF-67. Compared to the Co@C without CNT promotion, great enhancement of HMDA yield was achieved by Co@C CNT x . Characterizations suggested that CNT in the precursor modified the crystallization of the active Co centers as well as the surface composition in the Co@C CNT x . Strong Co-carbon interaction was formed via Co-N coordination caused by the facilitated re-dispersion of N- containing functionalities. The ethanol contact angle on Co@C CNT x was changed for better mass transfer and diffusion of reaction liquid on the catalyst. As a final result, the oxidation of cobalt sites was greatly suppressed in Co@C CNT 0.3 and Co@C CNT 0.5 , which was proved an essential factor for their fast reaction rates. 88 % yield of HMDA with the rate of 4.5 mol HMDA /mol Co /h was reached under a much higher utilization rate of Co center.
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APL Materials
·
2023
·Vol. 11
·期 10
·
IF 6.1
Li Xia,Deng Min,Cao Tingting,Ma Jun,Geng Shuo,Ren Yuan,Yao Mengqin,Liu Fei,Dong Yonggang
Formic acid (FA, HCOOH), as a liquid chemical hydrogen storage carrier with low cost, high hydrogen content, and convenient storage and transportation, has attracted extensive attention. Pd-based catalysts for hydrogen production from FA are easy to aggregate and deactivate in the reaction process, which hinders the further development of FA as a hydrogen storage carrier. Therefore, the exploitation of carriers with simple preparation methods and excellent performance can effectively improve the catalytic activity of Pd-based catalysts. Porous carbon and SiO 2 have been widely used for their unique structural properties, and the preparation of composite carriers by combining the advantages of both is a current research hotspot. Herein, this work synthesized C–SiO 2 for the deposition of Pd nanoparticles by a one-step method, and the obtained Pd/C–SiO 2 exhibits a superior FA dehydrogenation activity with a turnover frequency value of 1278 h −1 and a favorable stability with only a slight decrease in activity after five cycles.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Xinle Wang,Jin Chen,Yuzhao Ma,Jianye Shi,Yueying Wang,Xiaofeng Yang,Meidan Que,Yuxi Zhou,Yanjun Li
Two-dimensional (2D) transition metal carbide MXene (Ti 3 C 2 T x ) exhibits great potential in electromagnetic wave (EMW) absorbing materials due to its abundant surface functional groups and defects, tunable conductivity and high specific surface area. The Co@NC/TiO 2 /C composites were successfully synthesized through a solvothermal method and carbonization process using Ti 3 C 2 T x /Co-BTC as precursor. The incorporation of magnetic metal Co nanoparticles and Rutile-TiO 2 effectively addresses the issue of single loss mechanism in Ti 3 C 2 T x . The results show that CTC-100 exhibits excellent EMW absorption performance with a minimum reflection loss (RL) value of −51.3 dB at a thickness of only 1.48 mm, and the corresponding effective absorption bandwidth is (EAB, RL < −10 dB) 4.3 GHz. Simultaneously, by adjusting the matching thickness of the material from 1.29 mm to 5.0 mm, the EAB can achieve 15.42 GHz (from 2.85 GHz to 18 GHz). The excellent EMW absorption performance of CTC-100 composite is primarily attributed to the synergistic effect of magnetic loss and dielectric loss. This study provided an effective strategy for the design of Ti 3 C 2 T x -based EMW absorbing materials with high absorption intensity, reduced thickness, and broad effective absorption bandwidth (EAB).
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Nanoscale
·
2023
·Vol. 15
·期 39
·16188-16198
·
IF 6.7
Qingxue Lai,Hongmei Zheng,Wanying Zhang,Yi Sheng,Luanjie Nie,Jing Zheng
Fe–N–C catalysts with highly dispersed metal active centers were developed as promising non-precious metal materials for acidic oxygen reduction reaction (ORR) electrocatalysis. However, such kind of novel catalysts still suffer from major challenges in the manipulation of dispersion, utilization, and stability of the Fe-based metal centers. Herein, a N-rich molecular dual-guided pyrolysis strategy was proposed to develop an efficient yolk-shelled Fe–N–C ORR electrocatalyst. A unique yolk-shelled nanostructure with a relatively ordered shell and disordered yolk of a carbon skeleton was controllably constructed via this guided-pyrolysis route from the precursor of Fe-doped zeolitic imidazolate framework-8 (Fe-ZIF-8). Moreover, the atomic-level dispersion of Fe element in the carbon skeleton could be achieved via the dual guidance from phenanthroline and melamine molecules. The optimized Fe–N–C catalyst demonstrated a half-wave potential of 0.78 V vs. RHE in acid media, close to commercial 30% Pt/C, along with a small negative shift of 19 mV after an accelerated durability test. These enhanced electrocatalytic properties could be attributed to the preferred transformation of the Fe precursors to atomically dispersed Fe–Nx active configurations, as well as the enhanced three-phased interfacial reaction kinetics.
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ACS Biomaterials Science & Engineering
·
2023
·
IF 5.8
Kaibo Xu,Liqin Cao,Zhouyu Wang,Liu-ping Chen
Hemoperfusion (HP) is one of the most prominent therapies for treating uremia, hyperbilirubinemia, and acute drug toxicity. The comprehensive performance of currently used porous HP adsorbents needs to be improved due to the impediment to their synthesis strategy. Herein, green carbon dioxide-in-water high internal phase emulsions (C/W HIPEs) were utilized and emulsified with poly(vinyl alcohol) (PVA) for the formation of a heparin-mimetic chitosan oligosaccharides/poly(acrylamide-co-sodium 4-styrenesulfonate) [COS/P(AM-co-SSS)] monolith, which exhibited good mechanical properties, stable swelling performance, hydrophilic properties, anticoagulant effect, and low hemolysis. It showed a strong toxin adsorption capacity (415.2 mg/g for creatinine, 199.3 mg/g for urea, 279.5 mg/g for bilirubin, and 160 mg/g for tetracycline). The adsorption process of porous COS/P(AM-co-SSS) followed the pseudo-second-order kinetic and Langmuir isotherm models. Moreover, the porous materials had a strong electrostatic force on creatinine. The removal of creatinine by simulated in vitro blood perfusion was 80.2% within 30 min. This work provides a green preparation strategy for developing novel HP materials, highlighting their potential application value in blood and environmental purification.
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MICROCHEMICAL JOURNAL
·
2019
·
IF 3.206
Xiaoli Liu,Yanyi Fu,Qinglin Sheng,Jianbin Zheng
Herein, a simple electrochemical sensor for dopamine (DA) detection was developed based on Ag@C core-shell structure and Au nanocomposites (Ag@C/Au). The Ag@C core-shell nanoparticles were synthesized by one-pot hydrothermal method , which were supported on Au nanoparticles in situ reduction process. The as-prepared nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV–vis absorption spectra. The electrochemical investigations indicated that Ag@C/Au nanocomposites possessed intriguing properties towards DA. These results could be attributed to the synergistic effect of Ag@C with enhanced substrate accessibility and conductivity, Au nanoparticles with surface of negative charges. Under the optimum experimental conditions, the liner range was 0.5 μM to 27.5 μM, 27.5 μM to 0.2775 mM and 0.2775 mM to 4.278 mM. The detection limit was 0.21 μM (S/N = 3). Furthermore, the electrochemical sensor showed favorable selectivity in the presence of interferents such as ascorbic acid (AA) and uric acid (UA). In general, the work could provide a promising possibility to develop excellent electrochemical sensors for DA detection.
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DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 24
·8457-8466
·
IF 4.39
Shao Yan,Yanjie Liang,Yafei Chen,Jingwei Liu,Dongxun Chen,Zhengwei Pan
Visible and infrared persistent phosphors have gained considerable attention in recent years and are being widely used as glow-in-the-dark materials in dark environments. In contrast, the progress in persistent phosphors emitting at the other end of the spectrum, i.e., the shorter-wavelength ultraviolet-C (UVC; 200–280 nm), is rather slow. Here we report the design and synthesis of a well-performing Pr3+-doped UVC emissive persistent phosphor, Lu2SiO5:Pr3+, which exhibits intense UVC persistent luminescence peaking at 270 nm and a long persistence time of more than 12 h after excitation with a 254 nm UV lamp. Besides, the UVC persistent luminescence of a UV pre-irradiated sample can be repeatedly revived after repeated short-illumination with low-energy white light via a process called photostimulated persistent luminescence. Owing to the distinct spectral features of UVC light and the self-sustained luminescence properties, the UVC persistent luminescence of the Lu2SiO5:Pr3+ persistent phosphor can be clearly monitored and imaged using a corona camera in bright environments including direct sunlight and indoor light. The Lu2SiO5:Pr3+ persistent phosphor is expected to find promising applications in the covert optical tagging field.
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Scientific Reports
·
2021
·Vol. 11
·期 1
·1-10
·
IF 4.38
Yang Kun,Xu Jialu,Zhang Ming,Lin Daohui
Biochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH 4 ), exhibits better reduction performance for contaminants than bare NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into the interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe 2+ /Fe 3+ and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe 2+ and Fe 3+ , rather than adsorption, is responsible for the removal of Fe 2+ and Fe 3+ by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH 4 . In addition to SEM or P-TEM, therefore, C-TEM is a potential technique to characterize the interior morphology of NZVI/BC for better understanding the improved reduction performance of contaminants by NZVI/BC than bare NZVI.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Xin Ge,Weili Song,Xinzhi Chen,Chao Qian,Shaodong Zhou,Xuemin Liu
A tandem process of micellar catalysis and cloud point extraction (CPE) is developed for copper-catalyzed Ullmann C-S coupling reactions in water. The functional nonionic surfactant, amine terminated polyether M2070, affords nano-micelle environment in the aqueous system; the latter splits to two phases above the cloud point temperature (CPT). The nature of the micellar catalysis in M2070 aqueous was investigated by DLS, EDS, XPS, IR, TEM and 1 H NMR. M2070 was verified to provide nano-space for encapsulation and aggregation of the substrates. More importantly, the metallic micelle formed by M2070 chelating copper was identified. It is noteworthy that excellent productivity in pre-micellar catalysis of C-S coupling reactions was obtained with good tolerance of substrate. Finally, the water-micelle system was separated into two phases above the CPT thus to achieve the product separation. Furthermore, the M2070/water system can be recycled and reused.
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ACS Applied Energy Materials
·
2021
·
IF 6.024
Yuda Lin,Kehua Zhong,Junqing Zheng,Mingxing Liang,Guigui Xu,Qian Feng,Jiaxin Li,Zhigao Huang
Rational engineering of nanostructured anode materials is important to develop lithium-ion batteries (LIBs). In this study, hierarchical composites of fluoridated carbonaceous GeO2 (F-GeO2@C) with rich oxygen vacancies were prepared by a simple annealing method. It is found that F– ions not only exist in the carbon matrix but also replace O2– of metallic oxides. The abundant introduced oxygen vacancies can provide more active sites and contribute to better electronic conductivity. Moreover, density functional theory (DFT) calculations confirm that F-doping greatly changes the electronic structure of the GeO2 composite, exhibiting interesting metallic behavior. Consequently, the F-GeO2@C anode shows an enhanced initial Coulombic efficiency (ICE) value of 71.6% and delivers excellent rate capability, much higher than most reported GeO2-based anodes. The enhancement of the electrochemical performance for F-GeO2@C is attributed to the hierarchical nanostructure and F-doping by increased reaction kinetics, reversibility, and cycling stability. Thus, such rational fabrication of the composite can motivate other high-performance germanium-based materials in LIBs.
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Journal of Oleo Science
·
2021
·
IF 1.601
Xing Wang,Shujie Wang,Yang Nan,Guoqin Liu
Vitamin C (VC)-loaded oleogel (VCOG) with corn oil and monoglyceride stearate was used to replace lipid phase of margarine completely. The oxidative stability of VCOG was evaluated at 60±1°C in a lightproof oven for 18 days and the result showed that VCOG peroxide (> 6 days) and p-anisidine value (> 4 days) was significantly lower than that of bulk oil and VC-free oleogel (p < 0.05). Then, the margarine containing 79.70% VCOG (VCOGM) was in comparison with four commercial butter in sensory and physical characteristic. Results showed that firmness, solid fat content and trans fatty acid of VCOGM were in the lowest values while unsaturated fatty acid and adhesiveness of VCOGM was in the highest values. Furthermore, VCOGM presented the similar springiness, cohesiveness, gumminess, score appearance, texture, taste and overall impression to some/all commercial butters selected in this research (p > 0.05). These results implied that VC-loaded oleogel was an excellent alternative of lipid phase in margarine which confirmed by 55% “definitely buy” and 25% “try once-then decide”.
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RSC Advances
·
2021
·Vol. 11
·期 42
·26319-26325
·
IF 3.361
Xin Hao
High-efficiency, porous and renewable magnetic microwave absorbing (MA) materials have been enthusiastically pursued due to their suitable impedance matching, light weight, strong multiple scattering and the synergy effect of dielectric and magnetic loss. Herein, a three-dimensional (3D) Co@C/ANF aerogel, composed of magnetic MOF derivatives embedded in biomass aramid nanofiber (ANF), was prepared for the first time through a directional-freezing method followed by an annealing process. To evaluate their MA attenuation performance, the electromagnetic parameters of Co@C/ANF composites with different component ratios were measured at 2–18 GHz. Profiting from the preserved porous structure of MOF derivatives, the construction of multiple heterogeneous interfaces and suitable electromagnetic parameters, Co@C/ANF 2 : 1 exhibited a good MA performance of RLmin = −64.3 dB (indicating more than 99.99996% microwaves were absorbed) and EABmax = 6.8 GHz. Considering the admirable overall performance, the Co@C/ANF aerogel is deemed to be a promising candidate for the next-generation of lightweight, reproducible, and high-performance MA materials.
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