查看更多>>摘要：The photoreduction of soluble U(VI) to insoluble U(IV) with conjugated microporous polymers (CMPs) is a promising channel to remove uranium from radioactive wastewater efficiently. However, the rapid backward charge recombination and unsatisfactory forward charge transfer lead to undesirable photocatalytic activity of CMPs. Herein, for the first time, a series of D-A(1)-A(2) terpolymers is developed with statistical copolymerization through adjusting the monomer feed molar ratio (FMR) for photoreduction of uranium. Compared with D-A binary copolymer, such D-A(1)-A(2) terpolymers can inhibit charge recombination and simultaneously facilitate charge separation due to its larger dipole moment and giant built-in electric field. Therefore, the PTrSO-2 which the FMR is 0.75: 1.0: 0.75 achieves 99.5% photocatalytic U(VI) reduction efficiency within 120 min visible-light irradiation, outshining most reported photocatalysts for such applications. This work cultivates an emerging stratagem and unconventional thinking for the development of CMPs photocatalysts used in the effective treatment of radioactive wastewater.
查看更多>>摘要：Here we report an integrated reduced graphene oxide/polypyrrole hybrid aerogel with highly efficient photodegradation performance and ultrahigh solar-powered water evaporation for simultaneous freshwater production and decontamination from complex wastewater. The nanohybrids were successfully fabricated by the combined hydrothermal reduction and freeze-drying process. The pi-pi interactions between two components not only prevent the stacking of reduced graphene oxide nanosheets to endow aerogels with abundant water transport channels and ideal mechanical stability, but also facilitate the interactions with organic molecules to realize high removal efficiency toward volatile organic compounds (VOCs). The wide-spectrum light harvesting, photothermal effect and solar-driven photocatalysis in the hybrid aerogel are beneficial for the synergistically enhanced thermal-assisted photodegradation toward VOC-contaminated water with a water evaporation rate of 2.08 kg m(-2) h(-1) and a phenol removal efficiency of 94.8%. Our findings may help the development of novel functional nanostructures for applications in environmental remediation and solar steam generation.
查看更多>>摘要：Direct conversion of ethanol to butadiene (ETB) is a promising process for the production of renewable butadiene, but it still confronts great obstacles such as low butadiene selectivity and poor stability. Here, we report a hierarchical nano-sized ZnZr-Silicalite-1 multifunctional catalyst with high catalytic performance and stability in direct ETB process, and it was prepared by a facile one-pot crystallization process. The hierarchical nano-sized ZnZr-Silicalite-1 multifunctional catalyst achieved excellent butadiene selectivity of 61.4% and ethanol conversion of 89.8% at 350 degrees C and 0.38 h(-1). More importantly, it possessed superior stability compared to the previously reported catalyst systems. The effect of catalyst properties on catalytic performance were investigated using multiple characterized techniques. The results displayed that the ZnZr-Silicalite-1 catalyst possessed a hierarchical nano-sized structure, synergistic effects of various active centers, and suitably balanced acid-base properties. These properties realized excellent catalytic performance and stability for direct ETB conversion.
查看更多>>摘要：The reaction mechanism of the reverse water-gas shift reaction (rWGSR) over Au/ceria catalysts was investigated by monitoring the catalyst dynamics and reaction intermediates using operando and transient spectroscopies, as well as by DFT calculations. Combined operando Raman and UV-Vis spectroscopic analysis allows establishing a correlation between subsurface oxygen vacancies and catalytic activity. Comparison of different ceria support materials, i.e., polyhedra and polycrystalline sheets, reveals that the defect concentration is not rate-determinant. Using transient DRIFTS, we are able to identify individual steps of hydrogen dissociation on supported gold and to gain detailed insight into the reduction of CO2 via formate and carbonate formation. It is demonstrated that CO2 reduction is influenced by the surface pretreatment. Considering all spectroscopic findings, we propose an associative mechanism via carbonate and formate intermediates as the main route for the rWGSR over Au/ceria(111) catalysts, while a redox mechanism plays only a minor role.
查看更多>>摘要：Nanozyme has attracted great attention due to its diverse enzymatic catalytic activities. But there are still challenges in constructing novel nanozyme with robust catalytic activity. Here, we report an atomically dispersed and fully exposed Cu-3 cluster stabilized on defect-rich nanodiamond-graphene hybrid support (Cu-3/ND@G) with unique active adsorption sites, which benefit the adsorption and cleavage of O-2, resulting in enhanced oxidase-like and antibacterial activity. The catalytic rate constant of Cu-3/ND@G (K-cat = 1.474 x 10(-1) s(-1)) is higher than those of previously reported copper single atom oxidase mimics (0.5 x 10(-3) s(-1)) and even the commercial Pt/C mimics (1.01 x 10(-2) s(-1)). DFT calculation revealed that the atomically dispersed Cu-3 cluster as active center significantly improves the oxidase-like activity, attributing to the easy dissociation of O-2 into reactive oxygen species (center dot OH). The atomically dispersed Cu-3 cluster with an antibacterial rate of 100% in the NaAc buffer presents its potential application in the field of antibacterial materials.
查看更多>>摘要：Selective electrocatalytic conversion of NO3- to N-2 is an environmental-friendly strategy to close the anthropogenic nitrogen-based cycle. This work reported a metal-organic framework-derived electrocatalyst with earthabundant bimetallic sites, showing quantitative (similar to 97.9% conversion) and selective (similar to 99.3%) nitrate-to-N-2 transformation. More importantly, both post-catalysis concentrations of NO3- and NO2- meet the drinking water limit requirements, set by World Health Organization. The reaction intermediates and mechanistic pathways in electrocatalytic reduction of NO3- to N-2 are elucidated by a variety of in-situ experimental studies and DFT calculations. The enhanced and selective electrocatalytic performances are ascribed to the relay catalytic effects of the neighboring Fe-Ni catalytic sites residing in the porous carbon electrocatalysts, which are structurally determined by X-ray absorption spectroscopy (XAS) as well as calculated structural model, with Fe sites decreasing the reaction barrier for NO3- conversion and Ni centers facilitating the adsorption and activation of reaction intermediates (NO2-, NO* and N2O*).
查看更多>>摘要：Single-atom catalysts (SACs) can achieve ultimate atomic utilization of precious metals to improve water splitting's economy. However, active sites in SACs are usually insufficient. Therefore, we propose the use of porous Co1NC which is rich in defects as support to prepare Pt1/Co1NC by mild electrochemical reduction at room temperature. Pt1/Co1NC showed record-high hydrogen evolution reaction (HER) activity, with an overpotential of only 4.15 mV at a current density of 10 mA cm-2. Its mass activity reached 32.4 A mg- 1Pt at an overpotential of 20 mV, which is 54 times that of Pt/C. The turnover frequency was up to 32.86 s- 1 at 20 mV, with excellent stability in long-term service. Our strategy suggests that nitrogen/carbon defects are vital for anchoring&forming monodispersed Pt active sites while preventing agglomeration. These sites possess low energy barriers, as verified by theoretical simulations. Therefore, our method presents a technical breakthrough for reducing cost of hydrogen energy.
查看更多>>摘要：In this study, N/B co-doped biochars were employed as metal-free activators of peroxydisulfate (PDS) for tetracycline degradation, more importantly, the roles of dopants and the relative contribution of radical vs nonradical oxidations were comprehensively investigated. Integrating with electron paramagnetic resonance and kinetics calculations, we showed that co-doping N and B into biochars not only boosted the catalytic activity but also switched the radical PDS-activated process into the electron transfer-dominated nonradical process. Compared with pristine biochar/PDS systems (22%), the nonradical contribution of N/B co-doped biochar/PDS systems increased to 59%, exhibiting outstanding stability and selectivity. Galvanic oxidation tests and theoretical simulations unveiled that doped biochars as conductive tunnels accelerate the potential difference-driven electron transfer from the highest occupied molecular orbital of pollutants to the lowest unoccupied molecular orbital of PDS due to the lower energy gap. This study provided new insights into the critical role of heteroatom-doped carbocatalysts in PDS nonradical activation.
Pasha, MujaheedTong, YongfengMansour, Said A.Haik, Yousef...
14页
查看更多>>摘要：Seawater electrolysis offers a promising technology for environmental remediation and mass production of sustainable hydrogen. However, intricated synthetic routes, limited oxygen selectivity, and electrode corrosion severely hamper the practical viability of this technology. Here, we designed an effective strategy to assemble interface-rich, Au NCs decorated Gd-Co2B nanoflakes embedded in Tio(2) nanosheets grown on Ti foil (Au-GdCo2B@TiO2) to meet the multiple needs of electrodes for seawater electrolysis. Benefiting from the high electrical conductivity, superior intrinsic activity, and improved transfer coefficient, this free-standing, Au-Gd-Co2B@TiO2 electrocatalyst demonstrates outstanding performance towards overall seawater splitting needing a small overpotential of 510 mV to attain a geometric activity of 1000 mAcm(-2) in alkaline seawater. The higher activity and specificity of Au-Gd- Co2B@TiO2 are credited to the oxygen vacancies and the presence of the Co-Au surface. Furthermore, its super hydrophilic-aerophobic features, improved corrosion resistance, and impressive durability reveal its practical viability for actual seawater electrolysis.
查看更多>>摘要：The coronavirus disease 2019 (COVID-19) global pandemic poses a major threat to human health and health care systems. Urgent prevention and control measures have obstructed patients' access to pain treatment, and many patients with pain have been unable to receive adequate and timely medical services. Many patients with COVID-19 report painful symptoms including headache, muscle pain, and chest pain during the initial phase of the disease. Persistent pain sequela in patients with COVID-19 has a physical or mental impact and may also affect the immune, endocrine, and other systems. However, the management and treatment of neurological symptoms such as pain are often neglected for patients hospitalized with COVID-19. Based on the China's early experience in the management of COVID-19 symptoms, the possible negative effects of preexisting chronic pain in patients with COVID-19 and the challenges of COVID-19 prevention and control bring to the diagnosis and treatment of chronic pain are discussed. This review calls to attention the need to optimize pain management during and after COVID-19.
NSTL
Elsevier
Lippincott Williams & Wilkins