Single‐atom catalysts (SACs) have emerged as promising materials in heterogeneous catalysis. Previous studies reported controversial results about the relative level in activity for SACs and ...nanoparticles (NPs). These works have focused on the effect of metal atom arrangement, without considering the oxidation state of the SACs. Here, we immobilized Pt single atoms on defective ceria and controlled the oxidation state of Pt SACs, from highly oxidized (Pt0: 16.6 at %) to highly metallic states (Pt0: 83.8 at %). The Pt SACs with controlled oxidation states were then employed for oxidation of CO, CH4, or NO, and their activities compared with those of Pt NPs. The highly oxidized Pt SACs presented poorer activities than Pt NPs, whereas metallic Pt SACs showed higher activities. The Pt SAC reduced at 300 °C showed the highest activity for all the oxidations. The Pt SACs with controlled oxidation states revealed a crucial missing link between activity and SACs.
The oxidation state of Pt single‐atom catalysts (SACs) was controlled from highly oxidized to highly metallic states by reducing Pt single atoms deposited on defective ceria at various temperatures. The optimum oxidation state of the Pt SAC was found for maximizing the catalytic activity for the oxidation of CO, CH4, and NO.
The past decade has witnessed a phenomenal rise in nanotechnology research due to its broad range of applications in diverse fields including food safety, transportation, sustainable energy, ...environmental science, catalysis, and medicine. The distinctive properties of nanomaterials (nano-sized particles in the range of 1 to 100 nm) make them uniquely suitable for such wide range of functions. The nanoparticles when manufactured using green synthesis methods are especially desirable being devoid of harsh operating conditions (high temperature and pressure), hazardous chemicals, or addition of external stabilizing or capping agents. Numerous plants and microorganisms are being experimented upon for an eco–friendly, cost–effective, and biologically safe process optimization. This review provides a comprehensive overview on the green synthesis of metallic NPs using plants and microorganisms, factors affecting the synthesis, and characterization of synthesized NPs. The potential applications of metal NPs in various sectors have also been highlighted along with the major challenges involved with respect to toxicity and translational research.
Minimizing the use of precious metal catalysts is important in many applications. Single-atom catalysts (SACs) have received much attention because all of the metal atoms can be used for surface ...reactions. However, SACs cannot catalyze some important reactions that require ensemble sites. Here, Rh catalysts were prepared by treating 2 wt % Rh/CeO2 hydrothermally at 750 °C for 25 h. Nearly 100% dispersion was obtained, but the surface Rh atoms were not isolated (denoted as ENS). They catalyzed the oxidation of C3H6 or C3H8 at low temperatures, but these oxidations did not occur on the Rh SAC. When the simultaneous oxidation of CO, C3H6, and C3H8 was performed, the T 20 (temperature at conversion 20%) for CO oxidation increased significantly from 40 °C for sole CO oxidation to 180 °C on SAC due to the competitive adsorption of hydrocarbons. However, T 20 increased much less on ENS, from 60 to 100 °C. ENS exhibited superior activity for low-temperature oxidation. During hydrothermal treatment for 25 h, the Rh size initially increased from 2.3 to 6.7 nm then decreased to 0.9 nm. The surface hydroxyl groups formed on the catalyst surface help detach Rh atoms from Rh clusters, while preventing the reaggregation of dispersed Rh atoms into Rh clusters. This fully dispersed catalyst would have maximum atom-efficiency while catalyzing various surface reactions.
Salt tolerance is an important constrain for rice, which is generally categorized as a typicalglycophyte. Soil salinity is one of the major constraints affecting rice production worldwide, especially ...inthe coastal areas. Susceptibility or tolerance of rice plants to high salinity is a coordinated action ofmultiple stress responsive genes, which also interacts with other components of stress signaltransduction pathways. Salt tolerant varieties can be produced by marker-assisted selection or geneticengineering by introducing salt-tolerance genes. In this review, we have updated on mechanisms andgenes which can help in transferring of the salt tolerance into high-yielding rice varieties. We havefocused on the need for integrating phenotyping, genomics, metabolic profiling and phenomics intotransgenic and breeding approaches to develop high-yielding as well as salt tolerant rice varieties.
Halide perovskites have emerged as promising candidates for various applications, such as photovoltaic, optoelectronic and thermoelectric applications. The knowledge of the thermal transport of ...halide perovskites is essential for enhancing the device performance for these applications and improving the understanding of heat transport in complicated material systems with atomic disorders. In this work, the current understanding of the experimentally and theoretically obtained thermal transport properties of halide perovskites is reviewed. This study comprehensively examines the reported thermal conductivity of methylammonium lead iodide, which is a prototype material, and provides theoretical frameworks for its lattice vibrational properties. The frameworks and discussions are extended to other halide perovskites and derivative structures. The implications for device applications, such as solar cells and thermoelectrics, are discussed.
Coupling during bone remodeling refers to the spatial and temporal coordination of bone resorption with bone formation. Studies have assessed the subtle interactions between osteoclasts and ...osteoblasts to preserve bone balance. Traditionally, coupling research related to osteoclast function has focused on bone resorption activity causing the release of growth factors embedded in the bone matrix. However, considerable evidence from in vitro, animal, and human studies indicates the importance of the osteoclasts themselves in coupling phenomena, and many osteoclast-derived coupling factors have been identified. These include sphingosine-1-phosphate, vesicular–receptor activator of nuclear factor-κB, collagen triple helix repeat containing 1, and cardiotrophin-1. Interestingly, neuronal guidance molecules, such as slit guidance ligand 3, semaphorin (SEMA) 3A, SEMA4D, and netrin-1, originally identified as instructive cues allowing the navigation of growing axons to their targets, have been shown to be involved in the intercellular cross-talk among bone cells. This review discusses osteoclast–osteoblast coupling signals, including recent advances and the potential roles of these signals as therapeutic targets for osteoporosis and as biomarkers predicting human bone health.
Epidemiologic studies of Kawasaki disease (KD) have shown a new pattern or change of its occurrence suggestive of its pathophysiology or risk factors from the first patient with KD reported in 1961. ...The incidence of KD in Northeast Asian countries including Japan, South Korea, China, and Taiwan is 10-30 times higher than that in the United States and Europe. Knowing the true epidemiology of KD in each country and the availability of publications of KD epidemiology also could benefit general health care providers and general population. This would enable the early detection and treatment of KD, ultimately reducing the incidence of coronary artery complications and mortality. Therefore, efforts to investigate the true epidemiology of KD should be continued in every country using a questionnaire survey, National Health Insurance system data, or combined methods depending on each country's medical environment to ensure high-quality care of patients with KD.
The emission of volatile organic compounds (VOCs) has led to significant deterioration in air quality, making it imperative to ensure that these compounds are removed from emission sources before ...they are released into the atmosphere. In this context, the present study recycled spent primary batteries to use their zinc rods waste (ZRW) as a palladium catalyst support for the removal of harmful VOCs. To this end, palladium supported on ZRW (Pd/ZRW) catalysts were prepared and tested for the catalytic oxidation of benzene, methylbenzene and 1,2-dimethylbenzene. The physicochemical properties of the Pd/ZRW catalysts were carefully characterized by ICP-OES, BET, SEM, XRD, FE-TEM, XPS, and H2-TPR analyses. The main component of ZRW was identified as ZnO. Consistent with expectations, increases in the loading of Pd from 0.1 to 1.0 wt% in the Pd/ZRW catalysts resulted in enhanced VOCs removal efficiency. The reaction temperature required for the complete oxidation (100% removal efficiency) of methylbenzene and 1,2-dimethylbenzene on the 1.0 wt% Pd/ZRW catalyst was below 340 °C at a gas hourly space velocity of 50,000 h−1. TEM, XPS, and H2-TPR results implied that the enhancement of catalytic activity with the addition of Pd could be attributed to the readily movable surface lattice oxygen as well as the active component (Pd species). Ultimately, ZRW of spent primary batteries appear to show promise as a catalyst support for VOCs removal. This study has introduced a novel strategy for reducing air pollutants by utilizing waste, which promotes the disposal of hazardous solid waste and ensures clean air quality.
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•The zinc rods waste (ZRW) was separated from spent primary batteries.•The recovered zinc rods were used as a support for a palladium catalyst.•The Pd/ZRW catalysts removed harmful volatile organic compounds very efficiently.•The temperature at 100% C7H8 conversion was 340 °C for the 1.0 wt% Pd/ZRW catalyst.
Co3O4 is an attractive alternative to precious metal catalyst for CO oxidation due to its low cost and earth abundance, but its high catalytic activity is severely degraded in the presence of water. ...Here, we show that doping La into Co3O4 surfaces significantly enhances CO oxidation activity under moisture-rich condition. While bare Co3O4 is deactivated under moisture, the La-doped Co3O4 catalysts exhibit greatly improved activity and water resistance. The higher ratio of active Co3+ on the La-doped Co3O4 surface results in the enhanced activity. Especially, the La doping greatly reduces the formation of surface OH on the Co3O4 surface, which causes the poor water resistance. Density functional theory calculations reveal that the La doping suppresses the vacancy-assisted dissociative adsorption of H2O, resulting in less formation of surface OH and thereby mitigating water poisoning on the Co3O4 surface. This work can provide an insight into the surface restructuring for highly active and water-resistant Co3O4 catalysts.
All‐solid‐state lithium batteries (ASSLBs) are promising energy‐storage devices with high energy density and safety. However, the discharge capacity of ASSLBs that use sulfide solid electrolytes ...(SEs) and Ni‐rich cathode active materials (CAMs) deteriorates significantly during electrochemical cycling. Interfacial coatings between CAM and sulfide SEs are known to effectively alleviate capacity deterioration. Among the various coating materials, lithium phosphate (LPO) was selected and synthesized via atomic layer deposition (ALD). The crystal phase of the LPO thin film irreversibly changed, and the Li‐ion conductivity deteriorated after heat treatment. Additionally, particle ALD (P‐ALD) of LPO was successfully performed to completely passivate the CAM particles. Torque cells with the LPO‐coated CAMs showed excellent capacity retention, whereas the cells without the LPO coating showed a significantly deteriorated discharge capacity with increased internal resistances. The passivation effect of the LPO coating was confirmed by the cross‐sectional images from a FIB and scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM–EDS) dual system. We believe that the study will help us investigate the effects of side reactions between sulfide SEs and CAMs on the performance and stability of P‐ALD.
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