다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The construction of heterostructures is regarded as an excellent strategy to achieve efficient charge separation and improved photocatalytic activity. Herein, a series of Bi2MoO6/ZnO hierarchical heterostructured photocatalysts were synthesized by a solvothermal method. The morphology of Bi2MoO6 grown on the surface of ZnO nanorods could be controlled by adjusting the experimental conditions. The synthesized samples were characterized by various analytical techniques and their photocatalytic performance was evaluated by photocatalytic reduction of Cr(VI) under visible-light irradiation. Compared with those of pure Bi2MoO6 and ZnO, the Bi2MoO6/ZnO composites showed higher photocatalytic activity towards the reduction of Cr(VI). The enhanced photocatalytic activity was mainly attributed to the formation of a heterojunction between Bi2MoO6 and ZnO, which effectively facilitated the separation and transfer of electrons and holes. In addition, the Bi2MoO6/ZnO photocatalysts maintained good stability after three cycles of Cr(VI) photoreduction. A possible photocatalytic mechanism of the as-synthesized composites was proposed.

Fabrication of Bi2MoO6/ZnO hierarchical heterostructures with enhanced visible-light photocatalytic activity

Luminescent carbon quantum dots (CQDs) represent a new form of nanocarbon materials which have gained widespread attention in recent years, especially in chemical sensor, bioimaging, nanomedicine, solar cells, light-emitting diode (LED), and electrocatalysis. CQDs can be prepared simply and inexpensively by multiple techniques, such as the arc-discharge method, microwave pyrolysis, hydrothermal method, and electrochemical synthesis. CQDs show excellent physical and chemical properties like high crystallization, good dispersibility, photoluminescence properties. In particular, the small size, superconductivity, and rapid electron transfer of CQDs endow the CQDs-based composite with improved electric conductivity and catalytic activity. Besides, CQDs have abundant functional groups on the surface which could facilitate the preparation of multi-component electrical active catalysts. The interactions inside these multi-component catalysts may further enhance the catalytic performance by promoting charge transfer which plays an important role in electrochemistry. Most recent researches on CQDs have focused on their fluorescence characteristics and photocatalytic properties. This review will summarize the primary advances of CQDs in the synthetic methods, excellent physical and electronic properties, and application in electrocatalysis, including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reduction (HER), and CO2 reduction reaction (CO2RR).

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A Mini Review on Carbon Quantum Dots: Preparation, Properties, and Electrocatalytic Application.

Cu2O/BiVO4 heterostructures: synthesis and application in simultaneous photocatalytic oxidation of organic dyes and reduction of Cr(VI) under visible light

Improved performance of Ni/Al2O3 catalyst deriving from the hydrotalcite precursor synthesized on Al2O3 support for dry reforming of methane

In the ammonia borane (AB) hydrolysis reaction, overcoming the weak activation of H2O by metal catalysts can be achieved by introducing transition metal oxides (TMOs) for catalyst active-sites design. Herein, we uncovered that oxygen vacancy (VO)-attired Cu/Cu0.76Co2.24O4 dual-active-sites catalysts significantly increase the hydrogen production rate of AB hydrolysis. The turnover frequency of Cu/Cu0.76Co2.24O4-VO dehydrogenation in 0.10 M NaOH can reach 50.33 molH2/(molcat·min), which is 45.9 times that of metal Cu. By means of a joint experimental and computational study, the VO defects promote the formation of electron-rich surface of Cu0.76Co2.24O4, and the Cu also enriches the surface electrons due to the strong interaction with TMOs, which enhances the activation of O–H and B–H bonds, respectively, and significantly accelerates the rate-determining step of the reaction. This work demonstrates the important role of constructive defects in regulating surface electrons of dual-active-sites catalysts on the performance enhancement and provides a broader idea for the design of excellent AB hydrolysis catalysts. 

Oxygen Vacancy-attired Dual-active-sites Cu/Cu0.76Co2.24O4 drives Electron Transfer for Efficient Ammonia Borane Dehydrogenation

Synthesis of SnS2/WO3 nanocomposite with enhanced photocatalytic activity

Electrochemical water splitting is a promising approach for the production of H2 fuel while greatly limited by the sluggish anodic oxygen evolution reaction (OER). In this regard, searching for a highly efficient and durable OER catalyst with low cost, abundant active sites, and excellent durability is increasingly demanded. Herein, a facile one-pot hydrothermal method that using urea as pH regulator is demonstrated to engineer nanobundle-like CoNi layered double hydroxides (CoNi LDHs) with high surface areas and rich oxygen vacancies. As a result, by virtue of the nanobundle-like structure, abundant oxygen vacancies, as well as the modified electronic structures, the optimized Co1Ni0.3 LDHs can deliver the current density of 10 mA/cm2 with the overpotentials of only 266 mV, much superior than those of Ir/C, Co(OH)2, and Ni(OH)2 catalysts. More importantly, the resultant Co1Ni0.3 LDHs also possesses excellent stability catalytic activity without negligible activity decay for at least 22 h. Our work not only establishes a potential OER electrocatalyst, but also open up a new avenue for the design and development of highly active electrocatalysts with controlled shapes.

Construction of hierarchical bundle-like CoNi layered double hydroxides for the efficient oxygen evolution reaction

Chitosan has several shortcomings that limit its practical application for the adsorption of heavy metals: mechanical instability, a challenging separation and recovery process, and low equilibrium capacity. This study describes the synthesis of a magnetic xanthate-modified polyvinyl alcohol and chitosan composite (XMPC) for the efficient removal and recovery of heavy metal ions from aqueous solutions. The XMPC was synthesized from polyvinyl alcohol, chitosan, and magnetic Fe3O4@SiO2 nanoparticles. The XMPC was characterized, and its adsorption performance in removing heavy metal ions was studied under different experimental conditions. The adsorption kinetics fit a pseudo-second-order kinetic model well. This showed that the adsorption of heavy metal ions by the XMPC is a chemical adsorption and is affected by intra-particle diffusion. The equilibrium adsorption isotherm was well described by the Langmuir and Freundlich equations. The XMPC reached adsorption equilibrium at 303 K after approximately 120 min, and the removal rate of Cd(II) ions was 307 mg/g. The composite material can be reused many times and is easily magnetically separated from the solution. This makes the XMPC a promising candidate for widespread application in sewage treatment systems for the removal of heavy metals.

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Xihua Du

Papers

Improved performance of Ni/Al2O3 catalyst deriving from the hydrotalcite precursor synthesized on Al2O3 support for dry reforming of methane

Oxygen Vacancy-attired Dual-active-sites Cu/Cu0.76Co2.24O4 drives Electron Transfer for Efficient Ammonia Borane Dehydrogenation

Synthesis of SnS2/WO3 nanocomposite with enhanced photocatalytic activity

Construction of hierarchical bundle-like CoNi layered double hydroxides for the efficient oxygen evolution reaction

Xanthate-Modified Magnetic Fe3O4@SiO2-Based Polyvinyl Alcohol/Chitosan Composite Material for Efficient Removal of Heavy Metal Ions from Water