In Situ Monitored Self-Assembly of Three-Dimensional Polyhedral Nanostructures

The self-assembly of 3D nanostructures is a promising technology for the fabrication of next generation nanodevices and the exploration of novel phenomena. However, the present techniques for assembly of 3D nanostructures are invisible and have to be done without physical contact, which bring great challenges in controlling the shapes with nanoscale precision. This situation leads to an extremely low yield of self-assembly, especially in 3D nanostructures built with metal and semiconductor materials. Here, an in situ self-assembly process using a focused ion beam (FIB) microscopy system has been demonstrated to realize 3D polyhedral nanostructures from 2D multiple pieces. An excited ion beam in the FIB microscopy system offers not only a visualization of the nanoscale self-assembly process but also the necessary energy for inducing the process. Because the beam energy that induces the self-assembly can be precisely adjusted while monitoring the status of the self-assembly, it is possible to control the self-assembly process with sub-10 nm scale precision, resulting in the realization of diverse 3D nanoarchitectures with a high yield. This approach will lead to state-of-the-art applications utilizing properties of 3D nanostructures in diverse fields

Improved Charge Separation and CO₂ Affinity of In₂O₃ by K Doping with Accompanying Oxygen Vacancies for Boosted CO₂ Photoreduction

The CO2 photocatalytic conversion efficiency of the semiconductor photocatalyst is always inhibited by the sluggish charge transfer and undesirable CO2 affinity. In this work, we prepare a series of K-doped In2O3 catalysts with concomitant oxygen vacancies (OV) via a hydrothermal method, followed by a low-temperature sintering treatment. Owing to the synergistic effect of K doping and OV, the charge separation and CO2 affinity of In2O3 are synchronously promoted. Particularly, when P/P0 = 0.010, at room temperature, the CO2 adsorption capacity of the optimal K-doped In2O3 (KIO-3) is 2336 cm3·g–1, reaching about 6000 times higher than that of In2O3 (0.39 cm3·g–1). As a result, in the absence of a cocatalyst or sacrificial agent, KIO-3 exhibits a CO evolution rate of 3.97 μmol·g–1·h–1 in a gas–solid reaction system, which is 7.6 times that of pristine In2O3 (0.52 μmol·g–1·h–1). This study provides a novel approach to the design and development of efficient photocatalysts for CO2 conversion by element doping

Silole-Containing Polymer Nanodot: An Aqueous Low-Potential Electrochemiluminescence Emitter for Biosensing

A novel D–A conjugated polymer backbone containing silole and 9-octyl-9<i>H</i>-carbazole units was synthesized via Sonogashira reaction. This silole-containing polymer (SCP) was further used to prepare SCP dots with a nanoprecipitation method, which showed an electrochemiluminescence (ECL) emission at relatively low potential in aqueous solution. The strong anodic ECL emission could be observed at +0.4 V (vs Ag/AgCl) with a peak value at +0.78 V in the presence of tri-n-propylamine (TPrA) as a co-reactant, which came from the band gap emission of the excited SCP dots. The ECL emission could be quenched via resonance energy transfer from the excited SCP dots to an acceptor. Thus, a low-potential anodic ECL sensing strategy was proposed for ECL detection of the acceptor-related analytes. Using dopamine as the analyte, whose electro-oxidation product could act as the energy acceptor to quench the ECL emission of SCP dots, the ECL detection method showed a detection limit of 50 nM and high anti-interference ability. This work demonstrates an example of polymer dots as an ECL emitter and its potential application in ECL detection methodology

Friedel–Crafts Amidoalkylation via Thermolysis and Oxidative Photocatalysis

Friedel–Crafts amidoalkylation was achieved by oxidation of dialkylamides using persulfate (S₂O₈^2–) in the presence of the visible light catalyst, Ru­(bpy)₃Cl₂, at room temperature, via a reactive <i>N</i>-acyliminium intermediate. Alternatively, mild heating of the dialkylamides and persulfate afforded a metal and Lewis acid-free Friedel–Crafts amidoalkylation. Alcohols and electron-rich arenes served as effective nucleophiles, forming new C–O or C–C bonds. In general, photocatalysis provided higher yields and better selectivities

Light-Mediated Reductive Debromination of Unactivated Alkyl and Aryl Bromides

Cleavage of carbon–halogen bonds via either single-electron reduction or atom transfer is a powerful transformation in the construction of complex molecules. In particular, mild, selective hydrodehalogenations provide an excellent follow-up to the application of halogen atoms as directing groups or the utilization of atom transfer radical addition (ATRA) chemistry for the production of hydrocarbons. Here we combine the mechanistic properties of photoredox catalysis and silane-mediated atom transfer chemistry to accomplish the hydrodebromination of carbon–bromide bonds. The resulting method is performed under visible light irradiation in an open vessel and is capable of the efficient reduction of a variety of unactivated alkyl and aryl substrates

Construction of BiOIO₃/AgIO₃ Z‑Scheme Photocatalysts for the Efficient Removal of Persistent Organic Pollutants under Natural Sunlight Illumination

The efficient removal of persistent organic pollutants (POPs) in natural waters is vital for human survival and sustainable development. Photocatalytic degradation is a feasible and cost-effective strategy to completely disintegrate POPs at room temperature. Herein, we develop a series of direct Z-scheme BiOIO3/AgIO3 hybrid photocatalysts via a facile deposition–precipitation method. Under natural sunlight irradiation, the light intensity of which is ∼40 mW/cm2, a considerable rate constant of 0.185 min–1 for photodecomposing 40 mg/L MO is obtained over 0.5 g/L Bi@Ag-5 composite photocatalyst powder, about 92.5 and 5.3 times higher than those of pristine AgIO3 and BiOIO3. The photoactivity of Bi@Ag-5 for photodecomposing MO under natural sunlight illumination surpasses most of the reported photocatalysts under Xe lamp illumination. After natural sunlight irradiation for 20 min, 95% of MO, 82% of phenol, 78% of 2,4-DCP, 54% of ofloxacin, and 88% of tetracycline hydrochloride can be photodecomposed over Bi@Ag-5. Relative to the commercial photocatalyst TiO2 (P25), Bi@Ag-5 exhibits greatly higher photoactivity for the treatment of MO–phenol–tetracycline hydrochloride mixture pollutants in the scale-up experiment of 500 mL of solution, decreasing COD, TOC, and chromaticity value by 52, 19, and 76%, respectively, after natural sunlight irradiation for 40 min. The photodegradation process and mechanism of MO have been systematically investigated and proposed. This work provides an archetype for designing efficient photocatalysts to remove POPs