Molecular Catalysis
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2023
·
IF 4.6
Weikun Chen,Xiao Fu,Xiaoying Liu,Linmin Ye,Youzhu Yuan
N -alkylated piperazines can be synthesized by the thermal catalytic alkylation of piperazine with alkyl halides or alcohols in the presence of supported metal catalysts. However, these processes either discharge large amounts of waste or require harsh conditions. Here, we report the results of N -alkylation of piperazine with lower alcohols (methanol, ethanol, and propanol) without external hydrogen addition at room temperature in the presence of a TiO 2 -supported Pd catalyst (Pd/TiO 2 -P) prepared by photodeposition method. Compared with the catalysts prepared by the conventional chemical reduction or hydrogen reduction, the Pd/TiO 2 -P catalyst showed the highest conversion of piperazine and the best selectivity to N -alkypiperazines. The mechanistic studies indicated that this phenomenon occurs via tandem photocatalytic reactions involving alcohol dehydrgenation to aldehyde, aldehyde condensation with piperazine to enamine, and enamine hydrogenation to N -alkylated piperazines. Considering the experimental results of methanol isotope kinetics, the α-C–H cleavage of methanol to form hydroxymethyl radical (·CH 2 OH) was proven to be the rate-determining step in the N -alkylation reaction of piperazine with low carbon alcohols. The characterization and control experiments revealed that the size of Pd nanoparticles and the valence of Pd species were vital to the reaction. The Pd/TiO 2 -P catalyst with an average of 2.5 ± 0.5 nm Pd particles and approximately 68% Pd 0 species on surfaces presented the highest activity for the photocatalytic tandem reactions of methanol dehydrogenation and enamine hydrogenation.
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ACS Applied Energy Materials
·
2023
·
IF 6.4
Bin Wang,Pei-ya Li,Qian Dong,Li-qin Chen,Hai-qiang Wang,Pei-long Han,Tao Fang
Liquid organic hydrogen carrier technology (LOHC) is considered to be the most promising solution for hydrogen storage and transport, but its development is limited by the high cost of noble metal catalysts. In this paper, four kinds of Ni/Co bimetallic catalysts with different proportions were prepared by the impregnation method. The effects of the Ni/Co molar ratio and the reduction temperature on the hydrogenation performance of N-ethylcarbazole (NEC) were studied. The relationship between the structure and the properties of the catalyst was discussed by combining various characterization methods. The results show that when cobalt is added to 50%, the hydrogenation activity is the most significant. Meanwhile, 100% of NEC conversion and 98.99% of 12H-NEC selectivity were achieved. The hydrogenation capacity is 5.77 wt %, when the catalyst reduction temperature is 450 °C. The characterizations show that the two metals are uniformly doped and highly dispersed with a good pore structure, and the metal particles have good alloy morphology. The synergistic interaction between Ni/Co metals is the key factor for the remarkable catalytic activity of the catalyst. The design and application of highly efficient nonprecious metal hydrogenation catalysts provide more feasibility to promote the commercial development of liquid organic hydrogen carrier technology.
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JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
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2023
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IF 3.5
Lei Ni,Dongyan Yang,Yinshan Liu,Chenghao Li,Qiang Chen,Juncheng Jiang,Yong Pan
Reaction thermal runaway accidents occur frequently and occupy a high proportion in chemical accidents. Reducing accidents by controlling reaction temperature is of great implication to enhance the safety level of chemical processes. Phase change materials (PCMs) have a good energy storage potential, which can rapidly convert the reaction exotherm in the reaction process into its own phase change latent heat, urgently control the reaction temperature, and enhance the process thermal safety level. In this study, using n -octadecane as the core and melamine-formaldehyde (MF) resin as the shell, microencapsulated phase change materials (microPCMs) was made, which has a smooth spherical shape, good thermal stability , and a phase change enthalpy up to 162.87 J/g. The homogeneous esterification reaction of 2-butanol (2 B) and propionic anhydride (PA) was selected as the target reaction, and then the reaction was scaled up equivalently to investigate the effect of amplification to the reaction system. The results indicated that the temperature control of the esterification reaction system by microPCMs is the synergy between physical inhibition and chemical inhibition. The reaction temperature could be controlled by adding microPCMs, and the temperature control effect improved with the increase of microPCMs addition. In large scale reactors, microPCMs still has certain temperature control ability after being added.
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NANOTECHNOLOGY
·
2023
·Vol. 34
·期 12
·125501
·
IF 3.5
Shenna Chen,Yunping Hao,Ronghui Li,Yanxu Liu,Jinxia Li,Lina Geng
Recently, carbon dots (CDs) have exhibited promising applications in the fluorescence detection of various ions and biomolecules. In this work, one kind of nitrogen-doped CDs (N-CDs) with high fluorescence intensity was synthesized, characterized by transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier-transform infrared, UV–vis absorption spectra, and fluorescence spectra. The results show that the spherical and uniform N-CDs (quantum yield: 60.2%) have remarkable fluorescence properties and photostability, which makes N-CDs can be utilized as an 'on-off-on' sensor for Hg2+ and glutathione (GSH). In addition, the pH-sensitive behavior of N-CDs makes it also applicable to H+ detection under acid conditions (pKa = 3.53). The linear range of the 'turn-off' sensor detecting Hg2+ was 0.014–50 μM, with a 0.014 μM limit of detection (LOD). GSH was detected by the fluorescence 'turn-on' method with a linear range of 0.125–60 μM and a LOD of 0.125 μM. The outstanding performance of N-CDs makes it potential applications in ecological pollution and biomolecule visualization monitoring.
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Polymers
·
2022
·Vol. 14
·期 23
·5080
·
IF 4.967
Leixuan Li,Yan Xin,Fengze Wu,Xiangrong Lyu,Qiyuan Yao,Xiaoting Yin,Qiang Zhang,Wenjuan Shan,Yong Chen,Qiuxia Han
CyclicN-halamines are highly antimicrobial, very stable, and not susceptible to bacterial resistance. A polysiloxane delivery vehicle was synthesized to deliver cyclic imideN-halamine onto cellulose via a benign and universal procedure that does not require a harmful solvent or chemical bonding. In brief, Knoevenagel condensation between barbituric acid and 4-hydroxybenzaldehyde furnished 5-(4-hydroxybenzylidene)pyrimidine-2,4,6-trione, whose phenolic O−H was subsequently reacted with the Si−H of poly(methylhydrosiloxane) (PMHS) via silane alcoholysis. The product of silane alcoholysis was interpenetrated into cellulose in supercritical CO2(scCO2) at 50 °C, to form a continuous modification layer. The thickness of the modification layer positively correlated with interpenetration pressure in the experimental range of 10 to 28 MPa and reached a maximum value of 76.5 nm, which demonstrates the ability for tunable delivery, to control the loading of the imide N−H bond originating from barbituric acid unit. The imide N−H bonds on cellulose with the thickest modifier were then chlorinated into N−Cl counterparts usingtert-butyl hypochlorite, to exert a powerful biocidability, providing ~7 log reductions of bothS. aureusandE. coliin 20 min. The stability and rechargeability of the biocidability were both very promising, suggesting that the polysiloxane modifier has a satisfactory chemical structure and interlocks firmly with cellulose via scCO2interpenetration.Keywords:cyclic imideN-halamines;polysiloxane;delivery vehicle;antibacterial surface;cellulose;scCO2interpenetration
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高影响因子
Crystals
·
2023
·Vol. 13
·期 6
·983
·
IF 2.7
Hao Zhao,Zishuai Jiang,Chengyu Wang,Yudong Li
The research on rapid and efficient detection of microplastics in water is still in its early stages. Fluorescence feature recognition represents an important and innovative approach to microplastic detection. While carbon quantum dots have been widely used in various environmental detection methods, their use for detecting microplastics in water environments has been rarely reported. In this study, N and Cl co-doped carbon quantum dots were synthesized via a hydrothermal method. The heteroatom doping process endowed them with blue luminescence properties, and their adsorption for microplastics was improved through the introduction of positive and negative charges and intermolecular forces. By utilizing a combined mechanism of fluorescence and Rayleigh scattering, the detection of polystyrene microplastics with three different particle sizes was achieved. In the detection process, it exhibits excellent light stability. Notably, the nano-polystyrene exhibited a good nonlinear relationship within the range of 0.01 g/L to 0.001 g/L, with R2values of 0.923 and 0.980 and a detection limit of 0.4 mg/L. These findings provide a novel approach for the detection of nano microplastics.Keywords:lignin;carbon quantum dots;co-doping;microplastic detection
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DIAMOND AND RELATED MATERIALS
·
2023
·
IF 4.1
Hui Zhao,Feifei Nie,Shuhui Liu,Yuanhao Li,Kezhong Wu,Mingxing Wu
Molybdenum-based carbides , as one of the representatives of transition metal compounds, are a promising alternative to the expensive and resource constrained Pt-based counter electrode (CE) in dye-sensitized solar cells (DSSCs). Herein, a series of hierarchical α-MoC 1- x @N-doped carbon (MDNC) composites are transformed from the step-by-step pyrolysis of uniformly Mo-based compounds and dopamine precursors at the temperatures of 650, 750, 850, and 950 °C under N 2 atmosphere, respectively. The MDNC precursors were synthesized by a simple one-step self-polymerization in a water-in-oil system. And then, the obtained MDNC nanocrystalline composites can accelerate electron conduction and improve the electrocatalytic property of the tri-iodide reduction reaction (IRR) owing to the C carrier obtained through the pyrolysis process and the N-doped of α-MoC 1- x by the carbonization of dopamine and the high temperature nitrogen atmosphere. In addition, the distinct hierarchical structure of MDNC with well-developed porosity and high specific surface area can expose numerous active catalytic sites. The DSSCs using the MDNC series as CEs for I 3 − /I − exhibit power conversion efficiencies (PCE) of 5.99 %, 6.35 %, 6.57 % and 5.57 %, respectively, which were versus 5.83 % of Pt CE.
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JOURNAL OF POWER SOURCES
·
2023
·
IF 9.2
Lei Zhang,Bing Sun,Qinghua Liu,Lin Song,Teibang Zhang,Xiaobo Duan
Lithium (Li) metal anode has attracted extensive research interest, while lithium dendrites and the resulting irreversible effects have restricted its development. In this study, a thin and dense solid electrolyte interface is constructed by introducing 3-(1-pyridinio)-1-propane sulfonate (PPS), a pyridine functional groups additive in DME/DOL based electrolyte to inhibit the lithium dendrite growth. The preferential decomposition of PPS has resulted in a reduction of gas generation. Subsequently, this process leads to forming of an N-rich solid electrolyte interface , which has been found to cause a decrease in polarization potential and change the behavior of lithium deposition from dendrites to a more cellular Li metal surface. As a result, our proposed electrolyte provides multiple functionalities, including remarkable rate capability, cyclic stability, and coulombic efficiency. Significantly, Li | Li symmetrical cells exhibited a stable cycle over 1200 h at a high current density and capacity of 5 mA cm −2 /15 mAh cm −2 . We are optimistic that our proposed method can be employed in future research to identify electrolytes appropriate for use in lithium metal anodes.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Jilin Liu,Kai Yu,Qianlong Zhu,Zhiyuan Qiao,Hong Zhang,Jie Jiang
Electroreduction of carbon dioxide (CO2) to C2 products (ethylene and ethanol) using efficient catalysts is a feasible approach to alleviate the climate crisis. Cuprous oxide nanoparticles (Cu2O NPs) are a promising catalyst for C2 production but suffer from inherent selectivity and durability. To address this challenge, a Cu2O NPs-nitrogen-doped carbon nanotube (Cu2O NPs-NCNT) composite was prepared with carbon nanotubes (CNTs), Cu2O NPs, and phthalocyanine (Pc). The results indicate that Cu2O NPs-NCNT has excellent Faradic efficiency of C2 products (77.61%) at −1.1 V vs RHE, which is 103.43% higher than that of Cu2O NPs. In the potentiostatic electrolysis combined with Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements, Cu2O NPs-NCNT exhibited structural and catalytic current stability over 10 h. Finally, density functional theory calculations combined with XPS demonstrated that the NCNT in Cu2O NPs-NCNT can selectively absorb CO2 through specific N–CO2 interactions. Our work provides a unique strategy to promote the selectivity of Cu2O NPs for C2 production by introducing N-doped linear carbon materials to fabricate composite.
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Materials
·
2023
·Vol. 16
·期 14
·5137
·
IF 3.4
Yanling Jin,Jiayi Wang,Xin Gao,Fang Ren,Zhengyan Chen,Zhenfeng Sun,Penggang Ren
Titanium dioxide (TiO2) is an ideal photocatalyst candidate due to its high activity, low toxicity and cost, and high chemical stability. However, its practical application in photocatalysis is seriously hindered by the wide band gap energy of TiO2and the prone recombination of electron-hole pairs. In this study, C, N doped TiO2were supported on spent coffee grounds-derived carbon (ACG) via in situ formation, which was denoted as C, N–TiO2@ACG. The obtained C, N–TiO2@ACG exhibits increased light absorption efficiency with the band gap energy decreasing from 3.31 eV of TiO2to 2.34 eV, a higher specific surface area of 145.8 m2/g, and reduced recombination rates attributed to the synergistic effect of a spent coffee grounds-derived carbon substrate and C, N doping. Consequently, the optimal 1:1 C, N–TiO2@ACG delivers considerable photocatalytic activity with degradation efficiencies for methylene blue (MB) reaching 96.9% within 45 min, as well as a high reaction rate of 0.06348 min−1, approximately 4.66 times that of TiO2(0.01361 min−1). Furthermore, it also demonstrated greatly enhanced photocatalytic efficiency towards methyl orange (MO) in the presence of MB compared with a single MO solution. This work provides a feasible and universal strategy of synchronous introducing nonmetal doping and biomass-derived carbon substrates to promote the photocatalytic performance of TiO2for the degradation of organic dyes.Keywords:titanium dioxide;spent coffee grounds–derived carbon;C, N doping;photocatalytic degradation;organic dyes;dye mixture
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Zhezhu Nan,Hengyu Liu,Linrong Shi,Hongrui Zhu,Junjie Chen,Tali Ilovitsh,Daocheng Wu,Mingxi Wan,Yi Feng
Focused ultrasound, as a protocol of cancer therapy, might induce extracellular adenosine triphosphate (ATP) release, which could enhance cancer immunotherapy and be monitored as a therapeutic marker. To achieve an ATP-detecting probe resistant to ultrasound irradiation, we constructed a Cu/N-doped carbon nanosphere (CNS), which has two fluorescence (FL) emissions at 438 and 578 nm to detect ultrasound-regulated ATP release. The addition of ATP to Cu/N-doped CNS was conducted to recover the FL intensity at 438 nm, where ATP enhanced the FL intensity probably via intramolecular charge transfer (ICT) primarily and hydrogen-bond-induced emission (HBIE) secondarily. The ratiometric probe was sensitive to detect micro ATP (0.2–0.6 μM) with the limit of detection (LOD) of 0.068 μM. The detection of ultrasound-regulated ATP release by Cu,N-CNS/RhB showed that ATP release was enhanced by the long-pulsed ultrasound irradiation at 1.1 MHz (+37%, p < 0.01) and reduced by the short-pulsed ultrasound irradiation at 5 MHz (−78%, p < 0.001). Moreover, no significant difference in ATP release was detected between the control group and the dual-frequency ultrasound irradiation group (+4%). It is consistent with the results of ATP detection by the ATP-kit. Besides, all-ATP detection was developed to prove that the CNS had ultrasound-resistant properties, which means it could bear the irradiation of focused ultrasound in different patterns and detect all-ATP in real time. In the study, the ultrasound-resistant probe has the advantages of simple preparation, high specificity, low limit of detection, good biocompatibility, and cell imaging ability. It has great potential to act as a multifunctional ultrasound theranostic agent for simultaneous ultrasound therapy, ATP detection, and monitoring.
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JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Run Li,Ying Yang,Zezhou Zhang,Shaohan Lian,Quan Zhao,Chunfeng Song
As a promising strategy to reduce greenhouse gas emissions, carbon dioxide capture from industrial and power plants has been proposed. Due to its advantages of low consumption and a modest environmental impact, membrane technology has been widely used in the gas separation process. Advanced porous fillers can be successfully added into the polymer matrix to create mixed matrix membranes (MMMs) with simple processing and applicable gas separation performance. The high porosity and stability of microporous carbon materials make them desirable for use in the gas separation process. Herein, N-doped microporous carbon microparticles (NMCP) were successfully synthesized and incorporated into UV crosslinked polyethylene oxide (XLPEO) matrix membranes. Fast CO 2 transport channels are created in MMMs by rationally constructing NMCP fillers with ultra-micropores (∼0.53 nm), high-content heteroatoms (N, 13.94%), and two-dimensional morphology. The relationship between the structure of the NMCP samples and the gas separation performance of MMMs was discussed. Additionally, tests were conducted on the effects of NMCP loading, operating conditions, and long-term stability of NMCP/XLPEO membranes. NMCP/XLPEO membranes with a 2.5 wt% NMCP loading displayed a CO 2 permeability of 606 Barrer and a CO 2 /N 2 selectivity of 56.4, approaching the 2019 upper bound. This work offers a novel perspective to build fast gas transport channels in porous carbon-based MMMs for carbon capture.
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