Reaction Kinetics Mechanisms and Catalysis
·
2024
·
IF 1.7
Lu Tengfei,Wang Yongjie,Zhang Yi
In this study, Methane dehydrogenation aromatization (MDA) over the 1Zn3Pt/Al 2 O 3 -6Mo/HZSM-5 physically mixed catalyst overcame the thermodynamic limitations through an efficient two-step cascade reaction at 550 °C and atmospheric pressure. Meanwhile, MDA reaction realized long-term stability during 30 h with methane conversion of 2.6% and as high as 98% selectivity of aromatics. A series of characterizations of this bifunctional physically mixed catalyst proved that the bifunctional physically mixed catalyst inhibits the coke deposition induced by over-aromatization and deep dehydrogenation, and the added Zn promoter promotes hydrogen spillover on Pt metal and inhibits further the sintering of Pt particles, contributing to the stable cascade conversion of methane to aromatics at low temperatures.
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International Journal of Minerals Metallurgy and Materials
·
2024
·Vol. 31
·期 5
·899-906
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IF 5.6
Lei Haiping,Wei Tianwei,Tu Jiguo,Jiao Shuqiang
Incorporating a selenium (Se) positive electrode into aluminum (Al)-ion batteries is an effective strategy for improving the overall battery performance. However, the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction products. In this work, we aim to harness the advantages of Se while reducing its limitations by preparing a core–shell mesoporous carbon hollow sphere with a titanium nitride (C@TiN) host to load 63.9wt% Se as the positive electrode material for Al–Se batteries. Using the physical and chemical confinement offered by the hollow mesoporous carbon and TiN, the obtained core–shell mesoporous carbon hollow spheres coated with Se (Se@C@TiN) display superior utilization of the active material and remarkable cycling stability. As a result, Al–Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g −1 at a current density of 1000 mA·g −1 while maintaining a discharge specific capacity of 86.0 mAh·g −1 over 200 cycles. This improved cycling performance is ascribed to the high electrical conductivity of the core–shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN.
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 5
·1-13
·
IF 5.3
Hu Anqi,Chen Guoqing,Li Lei,Ma Chaoqun,Yang Taiqun,Gao Hui,Gu Jiao,Zhu Chun,Wu Yamin
Nitrogen, boron co-doped carbon quantum dots (gCQDs), and a coloration probe (PPD-NPs) with response to cobalt ions (Co 2+ ) were prepared by using 4-hydroxyphenylboric acid as the common precursor, with ethylenediamine and p-phenylenediamine (PPD) adopted as nitrogen-doped reagents, respectively. A noticeable brown-to-purple color change can be observed with the addition of Co 2+ , and a broad absorption band emerges at 535 nm. At the same time, gCQDs, which is introduced as the fluorescence signal source, will be significantly quenched due to the enhanced inner filtration effect, induced by the overlap between the emission spectrum of gCQDs and the emerging absorption band. Therefore, a colorimetric/fluorescent dual-mode sensing probe for Co 2+ is constructed by combining the recognition unit PPD-NPs and the fluorescent gCQDs into PPD-NP/gCQD. Under the optimized experimental conditions, the calculated limits of detection are 1.51 × 10 −7 M and 3.75 × 10 −7 M for the colorimetric mode and the fluorescence mode, respectively, well qualified for the determination of Co 2+ maximum permitted level in drinking water. The feasibility of the proposed method has been verified in tap water, lake water, and black tea samples. Graphical Abstract
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 11
·1-11
·
IF 5.3
Jin Yao,Ai Wenhui,Chen Ge,Zhang Guodong,Wang Fang,Zhou Ting,Zhang Zhiqing,Wang Xiufeng
CuO nanoparticles with good water solubility and uniform particle size were successfully prepared. Interestingly, the oxidase-like activity of CuO NPs was continuously enhanced by the addition of thiourea (TU), and the enzyme activity was further enhanced by the addition of aluminum ion (Al 3+ ). By systematically exploring and optimizing the experimental conditions, including the key parameters such as temperature, reaction time, and pH, a fluorescence-colorimetric dual-mode sensing system based on CuO nanoparticles was constructed. The detection range of TU and Al 3+ were 1-100 µM and 1-100 µM, respectively, and the selectivity and precision of detection were further improved. In addition, the catalytic mechanism of CuO NPs as oxidase-like catalysts and the specific process in the reaction were investigated. Finally, the nano-sensing system was successfully applied to the analysis of three real environmental samples, namely, tap water, lake water and river water, which provided an effective new strategy for the future development of nano-sensing technology for TU and Al 3+ . Graphical
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Nature Communications
·
2024
·Vol. 15
·期 1
·1-14
·
IF 14.7
Xie Liangyiqun,Cai Yanming,Jiang Yujing,Shen Meikun,Lam Jason Chun-Ho,Zhu Jun-jie,Zhu Wenlei
Direct converting low concentration CO 2 in industrial exhaust gases to high-value multi-carbon products via renewable-energy-powered electrochemical catalysis provides a sustainable strategy for CO 2 utilization with minimized CO 2 separation and purification capital and energy cost. Nonetheless, the electrocatalytic conversion of dilute CO 2 into value-added chemicals (C 2+ products, e.g., ethylene) is frequently impeded by low CO 2 conversion rate and weak carbon intermediates’ surface adsorption strength. Here, we fabricate a range of Cu catalysts comprising fine-tuned Cu(111)/Cu 2 O(111) interface boundary density crystal structures aimed at optimizing rate-determining step and decreasing the thermodynamic barriers of intermediates’ adsorption. Utilizing interface boundary engineering, we attain a Faradaic efficiency of (51.9 ± 2.8) % and a partial current density of (34.5 ± 6.4) mA·cm −2 for C 2+ products at a dilute CO 2 feed condition (5% CO 2 v/v), comparing to the state-of-art low concentration CO 2 electrolysis. In contrast to the prevailing belief that the CO 2 activation step ( \({{CO}}_{2}+{e}^{-}+\, * \,\to {}^{ * }{CO}_{2}^{-}\) ) governs the reaction rate, we discover that, under dilute CO 2 feed conditions, the rate-determining step shifts to the generation of *COOH ( \({}^{ * } {{CO}}_{2}^{-}+{H}_{2}O\to {}^{ * } {COOH}+{{OH}}^{-}({aq})\) ) at the Cu 0 /Cu 1+ interface boundary, resulting in a better C 2+ production performance.
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JOURNAL OF POROUS MATERIALS
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2024
·
IF 2.5
Xue Changhao,Hou Xiaohui,Sun Weijie,Yuan Xia
The acidic molecular sieve carrier Hβ supported non-noble metal catalyst Ni/Hβ was prepared by equal volume impregnation method and applied to the hydroalkylation of benzene to cyclohexylbenzene. The effects of calcination procedures on the particle size of Ni and the dispersion degree of metal on the carrier were investigated. Compared with the samples reduced by hydrogen after calcination, the active site Ni of Ni/Hβ obtained by direct thermal reduction in hydrogen is mainly dispersed on the surface of the carrier, with better metal dispersion and smaller particle size of Ni. Under the optimized reaction conditions, the initial pressure of H 2 is 2.5 MPa, the amount of catalyst is 4% of the total reaction liquid, and at the reaction temperature 190 °C for 3 h, the conversion of benzene is 38.4%, the selectivity of cyclohexylbenzene is 72.8%, the selectivity of cyclohexane is 5.2%, the selectivity of dicyclohexylbenzene is 16.5%, and the selectivity of other by-products decreased to 5.5%. After the catalyst was reused for 5 times, the conversion of benzene and selectivity of cyclohexylbenzene were both have a slight decrease. Characterization results showed that the structure of the recovered catalyst was stable, but the specific surface area and pore volume decreased significantly, the resulted problem of catalyst pore blockage can be restored through calcination treatment.
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 2
·1-10
·
IF 5.3
Xia Guangping,Hu Haoyun,Huang Yipeng,Ruan Guihua
Controllable synthesis of micro-flower covalent organic frameworks (MFCOFs) with controllable size, monodisperse, spherical, and beautiful flower shape was realized by using 2,5-diformylfuran (DFF) and p-phenylenediamine (p-PDA) as building blocks at room temperature. High-quality MFCOFs (5 − 7 μm) were synthesized by controlling the kind of solvent, amounts of monomers, catalyst content, and reaction time. The synthesized MFCOFs possessed uniform mesopores deriving from the intrinsic pores of frameworks and wide-distributed pores belonging to the gap between the petals. The MFCOFs-packed solid-phase extraction (SPE) column shows adsorption capacity of about 8.85 mg g −1 for 2,4-dichlorophenol (2,4-DCP). The MFCOF-based SPE combined with the HPLC method was established for the determination of 2,4-DCP in environmental water. The linear range of this method is 20–1000 ng mL −1 ( R 2 > 0.9994), and limit of detection (S/N = 3) is 10.9 ng mL −1 . Spiked recoveries were 94.3–98.5% with relative standard deviations lower than 2.3%. Graphical Abstract
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COLLOID AND POLYMER SCIENCE
·
2024
·
IF 2.2
Hu Guang,Khan Humayun,Ali Farman,Begum Siddiqa,Mehmood Sahid,Arif Umar,Ali Nisar,Hayat Mudassir
This study focuses on advancing epoxy-polyamide composites through the incorporation of chitosan, derived from crab shells, a sustainable polymeric bio filler known for its ability to enhance mechanical and thermal properties. Utilizing a solution casting technique, composites were fabricated by blending various concentrations of chitosan into the epoxy-polyamide matrix. Several analytical methods, including FT-IR, XRD, SEM, DSC, and mechanical testing, were used to evaluate the modifications and properties of the composites. FT-IR confirmed successful chitosan incorporation into the ER-PA composites, supported by SEM analysis showing improved structural integrity. XRD revealed prominent diffraction peaks, reflecting increased crystallinity and efficient chitosan integration. SEM indicated uniform chitosan dispersion on smooth surfaces, enhancing fracture toughness. Mechanical study of the 1% chitosan blend demonstrated superior results, with an elasticity of 6.79 GPa and fracture elongation of 2.2%, surpassing the 5% blend. DSC data showed improved thermal stability, with the uncured composite exhibiting endothermic behavior at 100 °C and exothermic behavior at 400 °C. TGA confirmed enhanced thermal properties up to 780 °C, particularly for the 1% Cs blend, which also displayed outstanding amorphous characteristics. Overall, the mechanical study confirmed Young’s best modulus, toughness, and tensile strength in the 1% blend. A noticeable shift toward higher temperatures during accelerated heating indicated enhanced material durability. These findings highlight the significant potential of chitosan to improve the mechanical strength and thermal stability of epoxy-polyamide composites, making them suitable for demanding engineering applications where endurance and performance are critical. Graphical abstract
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Science China-Chemistry
·
2024
·
IF 10.4
Qiang Yue,Cao Huaiman,Pan Yuzhen,Chi Yi,Zhao Liangyu,Yang Yingguo,Li Hai-Bei,Gao Yan,Sun Licheng,Yu Ze
Metal phthalocyanines (MPcs) have gained considerable research attention as hole-transport materials (HTMs) in perovskite solar cells (PSCs) because of their superb stability. However, the photovoltaic performance of MPc-based HTMs in PSCs is still lagging behind their small molecule and polymeric counterparts, largely due to their relatively low hole mobility. Here, we report for the first time the application of a copper naphthalocyanine derivative (namely t Bu-CuNc) as a hole-transport material (HTM) in perovskite solar cells (PSCs), and systematically study its optoelectronic and photovoltaic property compared with its CuPc analog (tBu-CuPc). Combined experiments disclose that the extension of π -conjugation from Pc to Nc core leads to not only an enhanced hole-carrier mobility associated with a stronger intermolecular interaction, but also an elevated glass transition temperature ( T g ) of 252 °C. The resultant PSCs employing t Bu-CuNc deliver an excellent power conversion efficiency of 24.03%, which is the record efficiency reported for metal complex-based HTMs in PSCs. More importantly, the encapsulated t Bu-CuNc-based devices also show dramatically improved thermal stability than the devices using the well-known Spiro-OMeTAD, with a T 80 lifetime for more than 1,000 h under damp-heat stress. This study unfolds a new avenue for developing efficient and stable HTMs in PSCs.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 32
·1-13
·
IF 2.8
Tang Guohui,Ren Qian,Chen Zheng,Ding Zixuan,Zhu Changtian,Chen Jin,Xu Gaojie,Liu Fenghua
In this study, an economical graphene-based electrothermal composite slurry was synthesized via a facile liquid-phase ball milling technique, employing mechanically exfoliated graphene as the conductive filler, aluminum dihydrogen phosphate as the binding agent and span85 as a dispersing agent. The resultant slurry was utilized to fabricate electrothermal coatings through screen printing technology. A comprehensive investigation was conducted to evaluate the influence of graphene concentration on the physical appearance, microstructure, electrothermal characteristics, and mechanical adherence of the electrothermal coatings. The findings indicate a positive correlation between graphene content and the electrical conductivity of the coatings, with a concurrent increase in the attainable heating temperature. Specifically, a coating comprising an equal ratio of graphene to aluminum dihydrogen phosphate exhibited a diminished square resistance of 16.10 Ω sq −1 and was capable of swiftly elevating to a temperature of 431 °C under an applied voltage of 36 V. Moreover, the coatings demonstrated robust adhesion to borosilicate glass, quartz glass, and stainless steel substrates, with particularly noteworthy adhesion strength of up to 49,160 mN on borosilicate glass. These attributes suggest a broad spectrum of high-temperature applications for the developed electrothermal coatings.
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JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 31
·14313-14327
·
IF 3.5
An Boyuan,Zhang Dongjie,Liu Yuyan,Fan Zhimin,Tan Huifeng,Xie Zhimin
Ti 3 C 2 T x (MXene)-based composites are considered electromagnetic wave absorption (EMA) materials due to their dielectric properties, microstructure, and synergistic interactions with magnetic particles. A better understanding of the effect of the MXene content in composites on the EMA performance is essential for their application, yet it remains unclear. Here, MXene/PU@Fe 3 O 4 (MPF) microspheres with different MXene contents were produced through the incorporation of magnetic particles and multiple electrostatic self-assembly processes. The results show that when the molar ratio of MXene to Fe 3 O 4 is less than 0.5:1, the EMA performance of the MPF microspheres gradually increases with increasing MXene content. MPF microspheres exhibit the best EMA performance when the molar ratio of MXene to Fe 3 O 4 is 0.5:1, with a maximum reflection loss (RL) of 44.0 dB and an effective absorption bandwidth (EAB) of 2.30 GHz. Further increases in this ratio led to an increase in the EAB but a slight reduction in the maximum RL. Additionally, the combination of the same MXene and Fe 3 O 4 nanoparticle ratio had no significant effect on the EMA performance. We expect that this work will enrich the EMA performance research on MXene-based composites.
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JOURNAL OF NANOBIOTECHNOLOGY
·
2024
·Vol. 22
·期 1
·1-16
·
IF 10.6
Zhang Xuwu,Zhang Xinyue,Liu Shiqi,Zhang Weidong,Dai Liang,Lan Xifa,Wang Desong,Tu Wenkang,He Yuchu,Gao Dawei
Background Elevated interstitial fluid pressure within tumors, resulting from impaired lymphatic drainage, constitutes a critical barrier to effective drug penetration and therapeutic outcomes. Results In this study, based on the photosynthetic characteristics of algae, an active drug carrier (CP@ICG) derived from Chlorella pyrenoidos a (CP) was designed and constructed. Leveraging the hypoxia tropism and phototropism exhibited by CP, we achieved targeted transport of the carrier to tumor sites. Additionally, dual near-infrared (NIR) irradiation at the tumor site facilitated photosynthesis in CP, enabling the breakdown of excessive intratumoral interstitial fluid by generating oxygen from water decomposition. This process effectively reduced the interstitial pressure, thereby promoting enhanced perfusion of blood into the tumor, significantly improving deep-seated penetration of chemotherapeutic agents, and alleviating tumor hypoxia. Conclusions CP@ICG demonstrated a combined effect of photothermal/photodynamic/starvation therapy, exhibiting excellent in vitro/in vivo anti-tumor efficacy and favorable biocompatibility. This work provides a scientific foundation for the application of microbial-enhanced intratumoral drug delivery and tumor therapy. Graphical Abstract
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