Engineering Lewis-Acid Defects on ZnO Quantum Dots by Trace Transition-Metal Single Atoms for High Glycerol-to-Glycerol Carbonate Conversion.

Efficient conversion of biomass wastes into valuable chemicals has been regarded as a sustainable approach for green and circular economy. Herein, a highly efficient catalytic conversion of glycerol (Gly) into glycerol carbonate (GlyC) by carbonylation with the commercially available urea is presented using low-cost transition metal single atoms supported on zinc oxide quantum dots (M-ZnO QDs) as a catalyst without using any solvent. A facile one-step wet chemical synthesis allows various types of metal single atoms to simultaneously dope and introduce Lewis-acid defects in the ZnO QD structure.

Photocatalytic Production of Ethanolamines and Ethylenediamines from Bio-Polyols over a Cu/TiO Catalyst.

Valorization of biomass-derived polyols into high-value-added ethanolamines and ethylenediamines is highly attractive. Herein, we report a one-step photocatalytic protocol to convert bio-polyols into a 60 % yield of ethanolamines and ethylenediamines over a multifunctional Cu/TiO catalyst. This catalyst enables a tandem process of photocatalytic polyol C-C bond cleavage and reductive amination in one pot at room temperature, and also allows the selective conversion of various bio-polyols and amines.

Reactant enrichment in hollow void of Pt NPs@MnOx nanoreactors for boosting hydrogenation performance.

In confined mesoscopic spaces, the unraveling of a catalytic mechanism with complex mass transfer and adsorption processes such as reactant enrichment is a great challenge. In this study, a hollow nanoarchitecture of MnO-encapsulated Pt nanoparticles was designed as a nanoreactor to investigate the reactant enrichment in a mesoscopic hollow void. By employing advanced characterization techniques, we found that the reactant-enrichment behavior is derived from directional diffusion of the reactant driven through the local concentration gradient and this increased the amount of reactant.

A highly selective red-emitting fluorescent probe and its micro-nano-assembly for imaging endogenous peroxynitrite (ONOO) in living cells.

Endogenous peroxynitrite plays a very important role in the regulation of life activities. However, validated tools for ONOO tests are currently insufficient. We designed a fluorescent probe TPA-F-NO with a low fluorescence background in water based on the D-π-A structure for the imaging of endogenous ONOO in living cells.

Heterogenization of Salen Metal Molecular Catalysts in Covalent Organic Frameworks for Photocatalytic Hydrogen Evolution.

Integrating a molecular catalyst with a light harvester into a photocatalyst is an effective strategy for solar light conversion. However, it is challenging to establish a crystallized framework with well-organized connections that favour charge separation and transfer. Herein, we report the heterogenization of a Salen metal complex molecular catalyst into a rigid covalent organic framework (COF) through covalent linkage with the light-harvesting unit of pyrene for photocatalytic hydrogen evolution.

Selective Oxidation of Glycerol into Formic Acid by Photogenerated Holes and Superoxide Radicals.

Photocatalysis is a promising technology for conversion of the glycerol into formic acid, but photocatalytic oxidation of C-C bonds in glycerol exhibits poor selectivity towards formic acid because the photogenerated radicals (e.g., hydroxyl radicals) further oxidize formic acid to CO .

Precise Drift Tracking for Transmission Electron Microscopy via a Thon-Ring Based Sample Position Measurement.

Visualizing how a catalyst behaves during chemical reactions using in situ transmission electron microscopy (TEM) is crucial for understanding the activity origin and guiding performance optimization. However, the sample drifts as temperature changes during in situ reaction, which weakens the resolution and stability of TEM imaging, blocks insights into the dynamic details of catalytic reaction. Herein, a Thon-ring based sample position measurement (TSPM) was developed to track the sample height variation during in situ TEM observation.

Data synchronization in operando gas and heating TEM.

Time-resolved correlations of the environment, the reaction products, the energy transfer and the material structures during the reaction processes make operando gas and heating TEM more and more attractive in recent years. The time delays existing among parameter measurement locations need to be calibrated for valid correlations. Otherwise, erroneous conclusions would be drawn, such as over/under-estimating the critical temperatures, mismatching the structure and composition relationships to activities, and so on.

Holistic Valorization of Hemp through Reductive Catalytic Fractionation.

Despite the increased use of hemp fiber, negligible attention has been given to upgrade the hemp hurd, which constitutes up to 70 wt % of the hemp stalk and is currently considered a low-value byproduct. In this work, valorization of hemp hurd was performed by reductive catalytic fractionation (RCF) in the presence of a metal catalyst. We found an unexpectedly high yield of monophenolic compounds (38.

Light-driven directional ion transport for enhanced osmotic energy harvesting.

Light-driven ion (proton) transport is a crucial process both for photosynthesis of green plants and solar energy harvesting of some archaea. Here, we describe use of a TiO/CN semiconductor heterojunction nanotube membrane to realize similar light-driven directional ion transport performance to that of biological systems. This heterojunction system can be fabricated by two simple deposition steps.

Yb-Alloyed CsPbI-CsPbI Perovskite Nanocomposites for Efficient and Stable Pure-Red Emission.

A series of Yb-alloyed CsPbYbI ( = 0, 0.2, 0.4, 0.

NbO-Based Photocatalysts.

Photocatalysis is one potential solution to the energy and environmental crisis and greatly relies on the development of the catalysts. Niobium pentoxide (NbO), a typically nontoxic metal oxide, is eco-friendly and exhibits strong oxidation ability, and has attracted considerable attention from researchers. Furthermore, unique Lewis acid sites (LASs) and Brønsted acid sites (BASs) are observed on NbO prepared by different methods.

Cascaded Excited-State Intramolecular Proton Transfer Towards Near-Infrared Organic Lasers Beyond 850 nm.

Near-infrared (NIR) organic solid-state lasers play an essential role in applications ranging from laser communication to infrared night vision, but progress in this area is restricted by the lack of effective excited-state gain processes. Herein, we originally proposed and demonstrated the cascaded occurrence of excited-state intramolecular proton transfer for constructing the completely new energy-level systems. Cascading by the first ultrafast proton transfer of <430 fs and the subsequent irreversible second proton transfer of ca.

Microstructural Investigation and On-Site Repair of Thin Pd-Ag Alloy Membranes.

Pd membranes act in an important role in H2 purification and H2 production in membrane reactors. Pd-Ag alloy membranes fabricated by consecutive electroless- and electroplating process on alumina tubes exhibited good stability under stringent heating/cooling cycles at a ramp rate of 10 K/min, imitating practical fast initiation or emergency shutdown conditions. Bilayer Pd-Ag membranes can form dense and uniform alloy after thermal treatment for 24 h at 823 K under H2 atmosphere, despite a porous structure due to the development of liquid-like properties above Tamman temperature to enforce the migrativity.

Dialing in Catalytic Sites on Metal Organic Framework Nodes: MIL-53(Al) and MIL-68(Al) Probed with Methanol Dehydration Catalysis.

Many metal organic frameworks (MOFs) incorporate metal oxide clusters as nodes. Node sites where linkers are missing can be catalytic sites. We now show how to dial in the number and occupancy of such sites in MIL-53 and MIL-68, which incorporate aluminum-oxide-like nodes.

Amine-Mediated Bond Cleavage in Oxidized Lignin Models.

Introducing amines/ammonia into lignin cracking will allow novel bond cleavage pathways. Herein, a method of amines/ammonia-mediated bond cleavage in oxidized lignin β-O-4 models was studied using a copper catalyst at room temperature, demonstrating the effect of the amine source on the selectivity of products. For primary and secondary aliphatic amines, lignin ketone models underwent oxidative C -C bond cleavage and C -N bond formation to generate aromatic amides.

Heteroatom-participated lignin cleavage to functionalized aromatics.

Lignin, the most abundant aromatic polymer in nature, enables sustainable supply of miscellaneous aromatics as green fuels and chemicals. Obtaining the value-added aromatics from lignin, though subjected to enormous research efforts, mainly relies on depolymerization induced by activated hydrogen species or oxygen species, delivering hydrocarbons and oxygenates. The future bio-refinery demands a broad spectrum of fine chemicals, especially those containing elements other than C, H and O.

Construction of hollow mesoporous silica nanoreactors for enhanced photo-oxidations over Au-Pt catalysts.

It is highly desirable to design hollow structures with multi-scale functions by mimicking cells for the construction of micro/nanoreactors. Herein, we report the construction of hollow-structured submicrometer-photoreactors with bimetallic catalysts loaded within mesoporous silicas. The synthesis parameters are optimized to study the evolution of hollow structure through hydrothermal treatment and an 'adhesive-contraction' formation mechanism is proposed.

Detection of atherosclerosis-related hypochlorous acid produced in foam cells with a localized endoplasmic reticulum probe.

We have synthesized a turn-on fluorescent probe, termed NB4OH, to detect cellular hypochlorite. NB4OH is mainly localized in the endoplasmic reticulum and detects ClO- in foam cells. The fluorescence change of the probe was explained by theoretical calculation as a PET process.

Aqueous Batteries Operated at -50 °C.

Insufficient ionic conductivity and freezing of the electrolyte are considered the main problems for electrochemical energy storage at low temperatures (low T). Here, an electrolyte with a freezing point lower than -130 °C is developed by using dimethyl sulfoxide (DMSO) as an additive with molar fraction of 0.3 to an aqueous solution of 2 m NaClO (2M-0.

ESIPT Fluorescence Probe Based on Double-Switch Recognition Mechanism for Selective and Rapid Detection of Hydrogen Sulfide in Living Cells.

A novel fluorescence probe, HBTSeSe, was designed and synthesized for the detection of HS with a double-switch mechanism of a broken diselenide bond followed by thiolysis of ether. Then, 2-(2'-hydroxyphenyl)benzothiazole (HBT) was released as fluorophore, which has large Stokes shift based on the excited state intramolecular proton transfer process. The probe responded selectively and rapidly to HS, with the fluorescence increased by 47-fold immediately after the addition of HS.

Substitution Dependent Ultrafast Ultraviolet Energy Dissipation Mechanisms of Plant Sunscreens.

An ultraviolet energy dissipation mechanism plays a critical role in the photoprotection effect of sunscreens. In this work, we discovered substitution dependent UV energy dissipation mechanisms of model plant sunscreen methyl sinapate (MS). We found that the initially populated V(ππ*) states of MS and -OMeMS relax to the ground state nonradiatively along an ultrafast trans-cis photoisomerization in tens of picoseconds.

New Insight into the Photoprotection Mechanism of Plant Sunscreens: Adiabatic Relaxation Competing with Nonadiabatic Relaxation in the → Photoisomerization of Methyl Sinapate.

A great deal of thermally instable form photoisomerization products will be formed from the thermally stable form of the plant sunscreens sinapate esters upon ultraviolet radiation. To reveal the photoisomerization mechanism of the -isomer, we explore the photodynamics of a model plant sunscreen methyl sinapate (MS) in the form in organic solution. The high photoisomerization quantum yield of the -isomer results in the relatively higher photostability of -MS.