Electrochemical gas evolution reactions are of vital importance in numerous electrochemical processes including water splitting, chloralkaline process, and fuel cells. During reactions, bubbles vigorously constantly forming influencing these processes. In the past few decades, extensive studies have been performed to understand bubbles, elucidate mechanisms how impact exploit new bubble-based strategies improve efficiency reactions. this feature article, we summarize classical theories as...

Two-dimensional covalent organic frameworks (COFs) are an emerging class of photocatalytic materials for solar energy conversion. In this work, we report a pair structurally isomeric COFs with reversed imine bond directions, which leads to drastic differences in their physical properties, photophysical behaviors, and CO2 reduction performance after incorporating Re(bpy)(CO)3Cl molecular catalyst through bipyridyl units on the COF backbone (Re-COF). Using combination ultrafast spectroscopy...

The electrochemical generation of individual H(2) nanobubbles at Pt nanodisk electrodes immersed in a 0.5 M H(2)SO(4) solution is reported. A sudden drop current associated with the transport-limited reduction protons observed i–V response radii less than 50 nm. This decrease (~95% blockage) corresponds to formation single nanobubble attached nanoelectrode that blocks proton transport surface. which occurs, i(nb)(p), independent scan rate and concentration (for [H(2)SO(4)] > 0.1 M),...

Single H2 nanobubble nucleation is studied at Pt nanodisk electrodes of radii less than 50 nm, where produced through electrochemical reduction protons in a strong acid solution. The critical concentration dissolved required for measured to be ∼0.25 M. This value ∼310 times larger the saturation room temperature and pressure was found independent type (e.g., H2SO4, HCl, H3PO4) nanoelectrode size. effects different surfactants on are consistent with classic theory. As surfactant H2SO4...

Ion current rectification (ICR) refers to the asymmetric potential-dependent rate of passage solution ions through a nanopore, giving rise electrical current-voltage characteristics that mimic those solid-state diode. Since discovery ICR in quartz nanopipettes two decades ago, synthetic nanopores and nanochannels various geometries, fabricated membranes on wafers, have been extensively investigated understand fundamental aspects ion transport highly confined geometries. It is now generally...

The development of nanopore fabrication methods during the past decade has led to resurgence resistive-pulse analysis nanoparticles. newly developed enable researchers simultaneously study properties a single nanoparticle and statistics large ensemble This review covers basic theory recent advances in applying extends more complex transport motion (e.g., stochastic thermal nanoparticle) unusual electrical responses response sensitive surface charge), followed by brief summary numerical...

The catalytic properties of bulk-immiscible alloys are less explored than their bulk-miscible counterparts due to inherent difficulties in synthesis and stabilization. development alternative synthetic methods can, however, provide routes toward nanoparticles with metastable randomly alloyed structures. In this study, we combine computational screening a microwave-based method target that show enhanced reactivity over pure metals for the oxygen reduction reaction (ORR). A number systems...

In this paper, we show that PtAu and PdAu random alloy dendrimer-encapsulated nanoparticles with an average size of ∼1.6 nm have different catalytic activity trends for allyl alcohol hydrogenation. Specifically, exhibit a linear increase in increasing Pt content, whereas maximum at Pd content ∼60%. Both experimental theoretical results suggest contrasting behavior is caused by differences the strength H binding on surfaces. The significant implications predicting performance bimetallic basis...

Paired electrolysis has a limited reaction scope for organic synthesis because it is often not compatible with reactions involving short-lived intermediates. We addressed this limitation using alternating current (ACE). Using trifluoromethylation of (hetero)arenes as model reaction, we showed that the yield was improved from 13% paired to 84% ACE. have also developed theory guiding rational design parameters future applications

In the present work, we report a novel colorimetric sensor array for rapid identification of heavy metal ions. The sensing mechanism is based on competition between thiols and urease binding with Due to different ion-binding abilities urea, percentages are free ions become catalytically active in presence varied ion-free catalyzes decomposition urea releasing ammonia changing pH analyte solution. Bromothymol blue, indicator, changes its color response metal-caused change. Three...

In this article, we address the fundamental question: "What is critical size of a single cluster gas molecules that grows and becomes stable (or continuously growing) bubble during evolving reactions?" Electrochemical reactions produce dissolved are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, often lead to formation gaseous bubbles. Herein, demonstrate measurements concentration, at instant prior nucleation an...

Atmospheric NO

Here, we report a unique electrosynthetic method that enables the selective one-electron oxidation of tertiary amines to generate α-amino radical intermediates over two-electron iminium cations, providing easy access arylation products by simply applying an optimal alternating current (AC) frequency. More importantly, have discovered electrochemical descriptor from cyclic voltammetry studies predict AC frequency for various amine substrates, circumventing time-consuming trial-and-error...

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals widely used for their oil water-repellent properties. Their environmental persistence potential health risks have raised significant concerns. As PFAS degrades through remediation or natural processes, they form complex mixtures of the original chemicals, transformation byproducts, degradation additives. Analyzing after presents analytical challenges due to possible chemical physical interactions, including ion pairing,...

A room-temperature Ni-catalyzed reductive approach to homocoupling of unactivated primary, secondary, and tertiary alkyl bromides is described. The catalytic system can be easily generated from air-stable cheap materials demonstrates broad functional group tolerance, thus allowing facile access useful dimeric triterpene lignan-like molecules. Moreover, the dimerization bromide 6 efficiently establishes sterically hindered vicinal quaternary carbons (C3a C3a′), which a key linkage intriguing...

Conical nanopores are a powerful tool for characterizing nanoscale particles and even small molecules. Although the technique provides wealth of information, such pores limited in their ability to investigate particle dynamics due high velocities through very short sensing zone. In this report, we demonstrate use applied pressure balance electrokinetic forces acting on 8 nm diameter Au nanoparticles as they translocate ∼10 orifice. This force means vary nanoparticle velocity by 3 orders...

We report the electrochemical generation of a single hydrogen bubble within cavity recessed Pt nanopore electrode. The electrode is conical pore in glass that contains micrometer-scale disk (1-10 μm radius) at base and nanometer-scale orifice (10-100 nm restricts diffusion electroactive molecules dissolved gas between bulk solution. formation H2 voltammetric experiments results from reduction H(+) 0.25 M H2SO4 solution; liquid-to-gas phase transformation indicated response by precipitous...

We present an origami paper-based electrophoretic device (oPAD-Ep) that achieves rapid (∼5 min) separation of fluorescent molecules and proteins. Due to the innovative design, required driving voltage is just ∼10 V, which more than 10 times lower used for conventional electrophoresis. The oPAD-Ep uses multiple, thin (180 μm/layer) folded paper layers as supporting medium This approach significantly shortens distance between anode cathode, this, in turn, accounts high electric field (>1 kV/m)...

We present the first bubble-nucleation-based electrochemical method for selective and sensitive detection of surfactants. Our takes advantage high surface activity surfactant analyte to affect bubble nucleation then transduces change in condition signal determining concentration. Using this method, we demonstrate quantitation perfluorinated surfactants water, a group emerging environmental contaminants, with remarkable limit (LOD) down 30 μg/L linear dynamic range over 3 orders magnitude....

ConspectusMetal chalcogenide quantum dots (QDs) are prized for their unique and functional properties, associated with both intrinsic (quantum confinement) extrinsic (high surface area) effects, as dictated by size, shape, characteristics. Thus, they have considerable promise diverse applications, including energy conversion (thermoelectrics photovoltaics), photocatalysis, sensing. QD gels macroscopic porous structures consisting of interconnected QDs pore networks in which the pores may be...

Abstract Here, we report CdS quantum dot (QD) gels, a three‐dimensional network of interconnected QDs, as new type direct hydrogen atom transfer (d‐HAT) photocatalyst for C−H activation. We discovered that the photoexcited QD gel could generate various neutral radicals, including α‐amido, heterocyclic, acyl, and benzylic from their corresponding stable molecular substrates, amides, thio/ethers, aldehydes, compounds. Its activation ability imparts broad substrate reaction scope. The...