Latest ArticlesNitric oxide reduction to ammonia by electrocatalysis is the potential application in the elimination of smog and energy conversion. In this work, the feasibility of the application of two-dimensional metal borides (MBenes) in nitric oxide electroreduction reaction (NOER) was investigated through density functional theory calculations. Including the geometry and electronic structure of five kinds of MBenes, the adsorption of NO on the surface of these substrates, the selective adsorption of hydrogen protons during the hydrogenation process, and the overpotential in the electrocatalytic ammonia synthesis process. As a result, MnB exhibited the most favorable catalytic performance according to the associative pathways, which is thermodynamically performed spontaneously, and WB has a minimum overpotential of 0.37 V vs. RHE in the process of ammonia production according to the dissociative pathway. Overall, our work is the first to explore the electrocatalytic NO through the dissociative mechanism to synthesize ammonia in-depth and proves that MBenes are efficient NO electrocatalytic ammonia synthesis catalysts. These research results provide a new direction for the development of electrocatalytic ammonia synthesis experimentally and theoretically.
Despite the continuously increased requirement on automated synthesis of medicines for distributed manufacturing and personal care, it remains a challenge to realize automated synthesis which requires solid-liquid phase reactions. In this work, we demonstrated an automated solid-liquid synthesis for gadopentetate dimeglumine, the most widely used magnetic resonance imaging (MRI) contrast agent. The high-efficiency reaction was performed in a 3D microfluidic chip which was fabricated by femtosecond laser micromachining. The structure of the chip realized 3D shear flow which was essential for highly efficient mixing and movement of the solid-liquid mixtures. Ultraviolet visible (UV-vis) spectrometer was employed for in-line analysis to help automation of this system. Comparing with the round-bottom flask system, this synthetic system showed significantly higher reaction rate, indicating the advantage of the 3D microfluidic technology in micro chemical engineering.
A large surface area with high active site exposure is desired for the nano-scaled electrocatalysts fabrication. Herein, taking NiMoO4 nanorods for example, we demonstrated the advantages of the microwave-assisted hydrothermal synthesis method compared to the traditional hydrothermal approaches. Both monoclinic structured NiMoO4 in the nanorods morphology are found for these samples but it is more time-saving and efficient in the Ni-Mo synergism for the catalyst obtained by microwave-assisted hydrothermal syntheses method. When evaluated for urea oxidation, the current density can reach 130.79 mA/cm2 at 1.54 V, about 2.4 times higher than that of the counterpart catalyst (54.08 mA/cm2). Moreover, largely improved catalytic stability, catalytic kinetics and rapid charge transfer ability are found on the catalyst obtained by the microwave-assisted approach. The high catalytic performance can be attributed to the high surface area and active site exposure of NiMoO4 nanorods formed by microwave irradiation. Considering the less time, facile synthesis condition and efficient components synergism, the microwave-assisted hydrothermal synthesis method might work better for the nanostructure electrocatalysts fabrication.
In the field of advanced oxidation processes (AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species (ROS) to decompose refractory pollutants. Perovskite oxide, an emerging catalyst in the field of AOPs, has been extensively studied in wastewater treatment. Nevertheless, the application of perovskite in AOP systems still faces some problems, such as leaching of metal ions, a small surface area, a low number of active sites, etc. Herein, this critical review comparatively examines the activation mechanisms of peroxymonosulfate, hydrogen peroxide, and peroxydisulfate. Furthermore, the formation pathways of oxidizing species based on recent advances in experimental and theoretical studies were evaluated. In addition, the impacts of water parameters and constituents such as initial pH, oxidant concentration, catalyst dosage, natural organic matter, halide, phosphate, and carbonate were discussed. Finally, a critical discussion and prospects of mechanism exploration and possible materials development are proposed to confront the existing challenges in the application of perovskite oxides in AOPs.
A simple and effective method for constructing highly efficient oxygen reduction catalysts with trace amount of isolated cobalt was firstly developed by the pyrolysis of Co-centered polyoxometalate@metal-organic framework (Co-POM@MOF). The Co-centered polyoxometalate ([CoW12O40]6−) was confined in the well-defined void space of ZIF-8 to achieve homogeneous dispersion of polyoxoanions, where the isolated Co centers were well surrounded by the W-O shell and ZIF-8 framework. The Co-POM@MOF-derived N-doping porous carbon (Co-W-NC) with trace cobalt content was facilely prepared by the pyrolysis of the Co-POM@MOF under Ar atmosphere. The single dispersion of polyoxoanions in the metal-organic framework with complete separation of Co center surrounding by W-O shell and ZIF-8 framework ensures the uniform dispersion of Co atoms, confirmed by the Fourier transform extended X-ray absorption fine structure measurement. The Co-W-NC composite catalysts exhibit high performance for oxygen reduction reactions with a half-wave potential of 0.835 V in 0.1 mol/L KOH solution with excellent durability, which is much superior to that of the control samples derived from the [PW12O40]@ZIF-8, and the commercial Pt/C. This work highlights a new insight for constructing highly efficient catalysts via the introduction of metal-centered polyoxometalate into metal-organic framework following the high temperature treatment process.
A novel iron-hydrogen battery system, whose Fe3+/Fe2+ cathode circumvents slowly dynamic oxygen reduction reaction and anode is fed with clean and cordial hydrogen, is systematically investigated. The maximum discharge power density of the iron-hydrogen battery reaches to 96.0 mW/cm2 under the room temperature. The capacity reaches to 17.2 Ah/L and the coulombic and energy efficiency are achieved to 99% and 86%, respectively, during the galvanostatic charge-discharge test. Moreover, stable cycling test is observed for more than 240 h and 100 cycles with the iron sulfate in the sulfuric acid solutions. It is found that air plasma treatment onto the cathode carbon paper can generate the oxygen-containing groups and increase the hydrophilic pores proportion to ca. 40%, enlarging nearly 6-fold effective diffusion coefficient and improving the mass transfer in the battery performance. The simple iron-hydrogen energy storage battery design offers us a new strategy for the large-scale energy storage and hydrogen involved economy.
As an antibiotic, sulfadiazine has posed a serious threat to humans and ecosystems due to its chronic toxicity. The advanced oxidation processes (AOPs) via heterogeneous catalytic activation of peroxymonosulfate (PMS) have significant potential for the degradation of antibiotics. However, there are multiple restrictions including non-specifically binding to target contaminants, which would deplete oxidation capacity, and lacking energy effectiveness due to inefficient utilization of reactive oxygen species (ROS). To overcome these obstacles, we adopted the "bait-hook & destroy" strategy in this study. Herein, we synthesized a novel micrometer-sized NiOOH hierarchical spheres assembled from nanosheets, which have relatively large specific surface areas and yield specified cavities to "bait-hook" sulfadiazine and PMS onto the surface cavities. This process was further conductive to effective generation of ROS and subsequently "destruction" of sulfadiazine with elevated mass transformation rate. 20.4% of sulfadiazine can adsorb to NiOOH surface in less than 30 min (0.0051 min−1), and then sulfadiazine was completely degraded in 90 min intervals in the NiOOH/PMS system. The degradation rate constant (k = 0.0537 min−1) was about 5.3, 2.5 and 2.2 times higher than that in Ni2O3/PMS, NiO/PMS and Ni(OH)2/PMS system, respectively. This was ascribed to the synergistic catalytic oxidation and adsorption process occurred on the surface of NiOOH. Appreciably, there were both non-radicals (1O2) and radicals (O2•− and SO4•−) involved in the NiOOH/PMS system, and 1O2 was distinguished as the dominated ROS for degradation of sulfadiazine. This study provides a novel strategy via synergistic adsorption and catalytic oxidation, and indicates that the micrometer-sized NiOOH hierarchical sphere as heterogeneous catalyst is an attractive candidate for potential application of the SR-AOPs technology in water treatment.
We have prepared well-resolved Nbn+ (n = 1–10) clusters and report here an in-depth study on the essentially different reactivity with N2 and O2, by utilizing a multiple-ion laminar flow tube reactor in tandem with a customized triple quadrupole mass spectrometer (MIFT-TQMS). As results, the Nbn+ clusters are found to readily react with N2 and form adsorption products NbnN2m+; in contrast, the reactions with O2 give rise to NbnO1−4+Oproducts, and the odd-oxygen products indicate O-O bond dissociation, as well as increased mass abundance of NbO+ pertaining to oxygen-etching reactions. We illustrate how N2 prefers a physical adsorption on Nbn+ clusters with an end-on orientation for all the products, and allow for size-selective Nbn+ clusters to act as electron donor or acceptor in forming NbnN2m+. In contrast to these nitrides, the dioxides NbnO2+ display much larger binding energies, with O2 always as an electron acceptor, corresponding to superoxide or peroxide states in the initial reactions. Density-of-states and orbital analyses show that the interactions between Nbn+ and O2 are dominated by strong π-backdonation indicative of incidental electron transfer; whereas weak π-backdonation and simultaneous σ donation interactions exist in NbnN2+. Further, reaction dynamics analysis illustrates the different interactions for N2 and O2 in approaching the Nbn+ clusters, showing the energy diagrams for N2 adsorption and O-O bond dissociation in producing odd-oxygen products. Fragment analyses with orbital correlation and donor-acceptor charge transfer are also performed, giving rise to full insights into the reactivities and interactions of such transition metal clusters with typical diatomic molecules.
We comment the recent paper which reported a series of TPA derivatives to show acid-induced tunable white light emission.
Wood-derived carbons have been demonstrated to have large specific capacities as the anode materials of lithium-ion batteries (LIBs). However, these carbons generally show low tap density and minor volumetric capacity because of high specific surface area and pore volume. Combination with metal oxide is one of the expected methods to alleviate the obstacles of wood-derived carbons. In this work, the composites of MnO loaded wood-derived carbon fibers (CF@MnO) were prepared via a simple and environmentally friendly method, showing decreased specific surface area due to the generation of MnO nanoparticles on carbon fibers. Furthermore, the CF@MnO compostites exhibit superior electrochemical performance as anode materials of LIBs, which show high reversible capacity in the range of 529–734 mAh/g at a current density of 100 mA/g. The optimal CF@MnO product (MnO: carbon = 1:2) delivers reversible capacity of 734 and 265.3 mAh/g at current density of 100 and 2000 mA/g, respectively. Besides, the material presents outstanding stability with coulombic efficiency around 100% after 200 cycles at a high current density of 400 mA/g, revealing a potential as promising anode materials for high-performance LIBs.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
