Mandal, SubrataNanavati, Sachin P.Willock, David J.Ananthakrishnan, Rajakumar...
20页
查看更多>>摘要：We developed a one-pot synthetic route to design Ag nanoparticles (NPs) coupled mixed ligand Ag(I) coordination polymer (CP), Ag@Ag(I)-CP (40% NH2) for photocatalysis. Initial combined (experimental and DFT) study on mixed ligand CPs demonstrates that a rational substitution of ligand L1 : 1,4-benzenedicarboxylate by L2: 2 amino 1,4-benzenedicarboxylate enhances porosity and reduction of energy gap (2.9 eV) due to highest occupied crystal orbital (HOCO; + 2.4 V vs. NHE) suitable for BA oxidation selectively to benzaldehyde (BD) ((E-BA/BD(0) = + 1.9 V). When Ag NP (similar to 6-7 nm) is in-situ encapsulated on CP, formed a coupled structure Ag@Ag(I)-CP (40% NH2), which offered advantages on BA oxidation (k (O-2) = 7.4 x 10(-4) min(-1); yield: 19.1% BD, and k (persulfate) = 38.7 x 10(-4) min(-1); yield: 54.1% BD) along with significant stability, reusability and competitiveness than other Ag or precious metal NPs. The new material offers numerous possibilities for applications in oxidative organic transformations reactions. The simple synthetic strategy demonstrated in this work for the coupling of Ag(I) based coordination polymers with metal nanoparticles at the molecular scale for semiconductor like applications under visible light will accelerate extensive research in near future.
Kovalskii, Andrey M.Volkov, Ilia N.Evdokimenko, Nikolay D.Tkachenko, Olga P....
16页
查看更多>>摘要：Environmental protection requires solving the problem of utilization and reduction of CO and CO2 emissions. Herein, Au/h-BN(O) and Pt/h-BN(O) nanohybrids are thoroughly analyzed in CO oxidation and CO2 hydrogenation reactions. The nanohybrids differ in catalytic particle size and particle distribution. The particles are smaller (1-6 nm) and display a narrower size distribution in the case of Pt-based nanomaterials. The Pt/h-BN(O) nanohybrids exhibit high catalytic activity in CO conversion and carbon dioxide hydrogenation reactions. For both systems, the oxidative state of BN support affects the catalytic activity. The possible catalytic reaction mechanisms are proposed based on DFT calculations. A charge density distribution at the Pt/h-BN interface increases oxygen absorption, thereby accelerating oxygen-associated chemical reactions.
查看更多>>摘要：High-entropy oxides (HEOs), as a new family of materials with five or more principal cations, have shown promising properties for various applications. In this work and inspired by inherent defective and strained structure of HEOs, photocatalytic CO2 conversion is examined on a dual-phase TiZrNbHfTaO11 synthesized by a two-step high-pressure torsion mechanical alloying and high-temperature oxidation. The HEO, which had various structural defects, showed simultaneous photocatalytic activity for CO2 to CO and H2O to H2 conversion without the addition of a co-catalyst. The photocatalytic activity of this HEO for CO2 conversion was better than conventional photocatalysts such as anatase TiO2 and BiVO4 and similar to P25 TiO2. The high activity of HEO was discussed in terms of lattice defects, lattice strain, light absorbance, band structure, photocurrent generation and charge carrier mobility to activation centers. The current study confirms the high potential of HEOs as a new family of photocatalysts for CO2 conversion.
查看更多>>摘要：Polymeric carbon nitride (g-C3N4) exhibits only mediocre catalytic activity in photocatalytic environmental remediation and energy conversion because of its limited light absorption and sluggish charge transfer. Herein, we assembled novel, tubular carbon nitride (D-TCN450) with nitrogen defects/boron dopants via a self-supramolecular reaction and NaBH4 thermal reduction approach. Advanced characterization results suggested that introducing the nitrogen defects/boron dopants can effectively promote light trapping, charge separation, and valance-band downshift. Density functional theory and electron spin resonance results further proved that the fusion of cyano groups (nitrogen defects) into the framework of D-TCN450 can facilitate oxygen adsorption to form superoxide radicals. As a result, D-TCN450 exhibited dramatically improved photocatalytic hydrogen evolution and photodegradation of tetracycline hydrochloride at a 4- and 9-fold enhancement compared to pristine g-C3N4, respectively. This integrated engineering strategy might provide a unique paradigm for the rational design of novel photocatalysts for sustainable remediation and energy innovation.
NSTL
Elsevier