Latest ArticlesHydrogen (H2) is a promising renewable energy which finds wide applications as the world gears toward low-carbon economy. However, current H2 production via steam methane reforming of natural gas or gasification of coal are laden with high CO2 footprints. Recently, methane (CH4) pyrolysis has emerged as a potential technology to generate low-carbon H2 and solid carbon. In this review, the current state-of-art and recent progress of H2 production from CH4 pyrolysis are reviewed in detail. Aspects such as fundamental mechanism and chemistry involved, effect of process parameters on the conversion efficiency and reaction kinetics for various reaction media and catalysts are elucidated and critically discussed. Temperature, among other factors, plays the most critical influence on the methane pyrolysis reaction. Molten metal/salt could lower the operating temperature of methane pyrolysis to < 1000 ℃, whereas plasma technology usually operates in the regime of > 1000 ℃. Based on the reaction kinetics, metal-based catalysts were more efficient in lowering the activation energy of the reaction to 29.5–88 kJ/mol from that of uncatalyzed reaction (147–420.7 kJ/mol). Besides, the current techno-economic performance of the process reveals that the levelized cost of H2 is directly influenced by the sales price of carbon (by-product) generated, which could offset the overall cost. Lastly, the main challenges of reactor design for efficient product separation and retrieval, as well as catalyst deactivation/poisoning need to be debottlenecked.
Herein, we constructed defective UiO-66 with rich Zr vacancy structure model, in which the defective structure was verified by various characterizations. Also, the Pb adsorption experiments affirmed that defective UiO-66 could display better adsorption and selective adsorption ability than that of perfect UiO-66. The results of partial density of states (PDOS) and Mulliken charge population indicated that the blue shift of O 2p and Zr 4d orbit induced the electron rearrangement of atoms closed to the bonding sites, while the positive charge number of Zr atoms decreased than before. Combining with the expansion of pore size, Pb atom was more inclined to transfer and bond with unsaturated coordination oxygens. More significantly, quantitative structure-activity relationships (QSARs) demonstrated that selective capture of Pb instead of Zn, Cu, Cd and Hg displayed by defective UiO-66 was determined jointly by bond strength, adsorption energy and electron transfer. This work provided some theoretical direction for the purpose of the fabrication of adsorbent and the investigation of mechanism.
Organic thermoelectric (OTE) materials and devices have garnered significant attention in the past decade for flexible and wearable electronics. Due to the numerous combinations of different backbones, side chains, and functional groups for polymer molecules, further efficient developments of high performance OTEs rely on reverse and rational molecular design as well as fundamental understanding to the structure-property relationship, which both require precise theoretical input. Recently, many theoretical efforts and progresses have been made to predict TE properties and develop high performance OTE materials. Here, we present first the general methods and principles for OTE theoretical calculations. Subsequently, the latest theoretical advances regarding the effects of molecular design, chemical doping, ambipolar charge transport etc., to TE conversion are carefully reviewed. These theoretical advances not only significantly deepen the fundamental understanding of OTEs, but also provide precise guidance to the molecular design of OTE materials. Finally, we propose several perspectives for future theoretical investigations of OTEs.
In Fenton-like oxidation, the catalyst directly influences the reaction mechanism for the degradation of pollutants from water. Here, a α-MnO2 catalyst (OAm-1) was synthesized via a self-assembly method with the assistance of a surfactant. OAm-1 possessed a large specific surface area of 221 m2/g, abundant mesoporous structures and a large proportion of Mn(Ⅲ). Further characterization exhibited that OAm-1 had abundant oxygen vacancies and excellent reducibility and conductivity. The adsorption and catalytic ability of OAm-1 were studied in the degradation of oxytetracycline (OTC) via the activation of hydrogen peroxide (H2O2). Through the radical quenching experiments, electron resonance spectroscopy (EPR), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) analysis, Mn(Ⅲ) of OAm-1 was proved to be the active sites for the chemisorption of OTC. Systematic electrochemical experiments and analysis have shown that a process of electron transfer mediated by OAm-1 occurred between the pollutant and H2O2 during a Fenton-like reaction. This work experimentally verifies the electron transfer process dominated nonradical mechanism over α-MnO2, which is helpful for understanding the catalytic mechanism of the Fenton-like oxidation.
The isolation of circulating tumor cells (CTCs) from complex biological samples is of paramount significance for advancing cancer diagnosis, prognosis, and treatment. However, the low concentration of CTCs and nonspecific adhesion of white blood cells (WBCs) present challenges that hinder the efficiency and purity of captured CTCs. Microfluidic-based strategies utilize precise fluid control at the micron level to incorporate specific micro/nanostructures or recognition molecules, enabling effective CTCs separation. Moreover, by employing surface modification designs that exhibit exceptional anti-adhesion properties against WBCs, the purity of isolated CTCs can be further enhanced. This review offers an in-depth exploration of recent advancements, challenges, and opportunities associated with microfluidic-based CTCs isolation from biological samples. Firstly, we will comprehensively introduce the microfluidic-based strategies for achieving high-efficiency CTCs isolation, which includes the morphological design of microchannels for physical force-based CTCs isolation and the specific modification of microchannel surfaces for affinity-based CTCs isolation. Subsequently, a review of recent research advances in microfluidic-based high-purity CTCs isolation is presented, focusing on strategies that decrease the nonspecific adhesion of WBCs through surface micro-/nanostructure construction or chemical and biological modification. Finally, we will summarize the article by providing the prospective opportunities and challenges for the future development of microfluidic-based CTCs isolation.
The extraction of radioactive minor actinides (An(Ⅲ)) from lanthanides (Ln(Ⅲ)) is an extremely important step in nuclear waste reprocessing. Designing ligands with high-performance actinide-selectivity remains an essential task. Recent works have reported that some polyazole based ligands exhibit good An(Ⅲ)/Ln(Ⅲ) separation performance. Herein, we first evaluated the effects of different polyazole side chains on the Am(Ⅲ)/Eu(Ⅲ) selectivity by exploring three pyridine-derived polyazole ligands L1, L2 and L3 with 1,2,4-triazole, 1,2,3-triazole, and pyrazole side chains, respectively, using scalar relativistic theoretical methods. The coordination structures, bonding properties and thermodynamic behaviors of AmL(NO3)3 and EuL(NO3)3 complexes were investigated, which clarifies that the side chains do affect the electronic structure of ligand and its selectivity for Am(Ⅲ)/Eu(Ⅲ) ions. Moreover, L1 with 1,2,4-triazole side chains exhibited the highest selectivity for Am(Ⅲ) over Eu(Ⅲ) while the lowest complexation ability for metal ions among the three pyridine-derived polyazole ligands. Subsequently, we designed a new ligand L4 containing 1,2,4-triazole side chains and a preorganized phenanthroline backbone. Theoretically, such a new ligand was verified to show stronger complexation ability and higher selectivity for Am(Ⅲ)/Eu(Ⅲ) ions than L1. This work clarifies the complexation nature of polyazole based ligands with Am(Ⅲ)/Eu(Ⅲ) ions and provides design strategies for highly efficient polyazole based ligands for An(Ⅲ)/Ln(Ⅲ) separation.
Heterogeneous porous carbon (PC) materials have gained unique importance in the catalysis community due to their captivating properties, including high specific surface area, tunable porosity, and functionality. PC can play a prominent role in the sustainable synthesis of functional heterocycles, as they are a low-cost alternative while being an efficient and user-friendly material. This review examines the preparation and applicability of these carbonaceous materials used as catalysts or support for biologically active heterocycles synthesis, including hydrogenation, oxidation, oxidative dehydrogenation, cross-coupling, and other organic reactions. Moreover, the challenges, potential future development directions, and opportunities in the synthesis of potent bioactive heterocycles over PC materials have been addressed. This review will inspire further research to explore novel PC materials and their implications in heterocyclization.
In recent years, the application of smartphone in various fields has received great attention, and it has become a promising tool in virus detection, data processing and data exchange. During the rapid spread of COVID-19 around the world, many traditional detection methods have been combined with smartphone to assist in the analysis and detection of the novel coronavirus (SARS-CoV-2), including electrochemistry, fluorescence and colorimetry. With the gradual development of artificial intelligence (AI), the combination of AI and smartphone to analyze SARS-CoV-2 was also the focus of research. Based on the summary of the traditional methods combined with smartphone to detect SARS-CoV-2 virus, in addition to AI-based data processing, AI algorithms are also employed for SARS-CoV-2 detection itself. This review discussed both strategies and focused on the application of the former. The combination of AI algorithm and smartphone to detect SARS-CoV-2 has high accuracy, which is more conducive to meeting the needs of portable detection. In addition, the classification of SARS-CoV-2 virus samples in biological fluids such as blood and saliva was also discussed. Finally, this paper briefly discussed the limitations of using smartphone analysis to detect SARS-CoV-2, as well as the prospect and future development of virus detection. In conclusion, the detection methods based on smartphone and AI algorithms show great potential in the detection of SARS-CoV-2 and can be a valuable complement to traditional analysis methods.
Effective adjustment and control of the oxidation state of plutonium (Pu) and neptunium (Np) is an indispensable component of Np/Pu separation in spent nuclear fuel reprocessing. Some hydrazine derivatives including methylhydrazine (CH3N2H3) effectively achieves the reduction of Np(Ⅵ) to Np(Ⅴ) without reducing Pu(Ⅳ). Herein, we explored the reduction mechanisms of Pu(Ⅳ) and Np(Ⅵ) by CH3N2H3 in HNO3 solution using scalar-relativistic density functional theory. We elucidated the difference in the reduction mechanism between Np(Ⅵ) and Pu(Ⅳ) ions by CH3N2H3. The energy barrier for the reduction of [NpⅥO2(H2O)5]2+ and [NpⅥO2(NO3)(H2O)3]+ by CH3N2H3 is largely different due to the coordination of nitrate ion. Moreover, the energy barrier of the reduction of [NpⅥO2(H2O)5]2+ is apparently lower than that of [PuⅣ(NO3)2(H2O)7]2+, which is in line with the experimental observations. The results of Mayer bond order and localized molecular orbitals clarify the structural evolution of the reaction pathways. Analysis of the spin density demonstrates that the first Np(Ⅵ) and Pu(Ⅳ) reduction belongs to the outer-sphere electron transfer and the second Np(Ⅵ) and Pu(Ⅳ) reduction is the hydrogen transfer. This study explains theoretically why CH3N2H3 reduces Np(Ⅵ) but not Pu(Ⅳ), and helps to design promising reductants for the Np/Pu separation in spent nuclear fuel reprocessing.
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