Creative approaches to the design of catalytic nanomaterials are necessary in achieving environmentally sustainable energy sources. Integrating dissimilar metals into a single nanoparticle (NP) offers unique avenue for customizing activity and maximizing surface area. Alloys containing five or more equimolar components with disordered, amorphous microstructure, referred as High-Entropy Metallic Glasses (HEMGs), provide tunable performance based on individual properties incorporated metals....

Experimental electrochemistry offers unique opportunities for interactive instruction at all levels of education; however, widespread adoption in curricula is hindered by high costs associated with electrochemical instrumentation. Thus, the development affordable instruments represents an essential step toward making accessible to everyone. While numerous commercially available three-electrode potentiostats exist, two-electrode provide a simple and inexpensive alternative. Herein, we present...

Per- and polyfluoroalkyl substances (PFAS) are emerging as a hazardous class of environmental micropollutant, robust, sensitive, inexpensive sensing modalities needed to detect the earliest onset contamination surface water. Here, we present molecularly imprinted polymer (MIP)-modified microelectrode (r = 6.25 μm) sensor for quantification pervasive PFAS, GenX (HFPO-DA), in water obtained from Haw River North Carolina. A 20 nm film o-phenylenediamine was electropolymerized presence generate...

We demonstrate a method to electrodeposit and observe the electrocatalysis of small platinum clusters nanoparticles (NPs) in real time as they form on an ultramicroelectrode (UME). Water droplets ( rdrop ∼ 700 nm), stabilized by sodium dodecyl sulfate (SDS), were suspended solution dichloromethane (DCM) tetrabutylammonium perchlorate ([TBA][ClO4]), which was used mitigate charge balance during droplet electrolysis. When collided with UME biased sufficiently negative drive water reduction,...

Prodigious resources are currently being devoted to control the size and morphology of metal nanoparticles (NPs). Several homogeneous chemical photochemical techniques exist for synthesis NPs; however, these synthetic methods generally leave a distribution NP shapes sizes require stabilizing ligand prevent aggregation. Electrodeposition NPs onto conductive surfaces is versatile technique. However, spatial on surface difficult attain, even well-behaved materials like highly oriented pyrolytic...

Reactivity at phase boundaries is central to many areas of chemistry, from synthesis heterogeneous catalysis. New tools are necessary gain a more detailed understanding processes occurring these boundaries. We describe series experiments visualize using electrogenerated chemiluminescence (ECL) on glassy carbon electrodes. By taking advantage the solubilities ECL luminophore and coreactant in different liquid phases, we demonstrate that interface various phases (i.e., formed between water...

Porous metal nanoparticles (NPs) are important to a variety of applications; however, robust control over NP porosity is difficult achieve. Here, we demonstrate using nanodroplet-mediated electrodeposition by introducing glycerol into water droplets. Porosity approached 0 under viscous conditions (>6 cP), and intermediate viscosities allowed the fine-tuning between 15%. This method also for average pore radius (1 5 nm) density (2 6 × 1015 pores per square meter). Reduced mass transfer within...

We demonstrate the application of open circuit potentiometry (OCP) to measure enzyme turnover kinetics, kturn. The electrode surface will become poised by addition a well-behaved redox pair, such as ferrocenemethanol/ferrocenium methanol (FcMeOH/FcMeOH+), which acts cosubstrate for enzymatic process. A measurable change in potential results when an consumes one-electron transfer mediator. Glucose oxidase was studied test-case, but method is generalizable across oxidoreductase enzymes that...

We report a set of voltammetric experiments for studying redox reactions and ion transfer in water microdroplets emulsified 1,2-dichloroethane (DCE). The electrochemistry (rdrop ∼ 700 nm) loaded with either ferrocyanide ([Fe(CN)6]4–) or ferricyanide ([Fe(CN)6]3–), chosen due to their hydrophilic nature, was tracked using cyclic voltammetry. These heterogeneous necessitated at the droplet interface maintain charge balance two liquid phases during oxidation reduction, which facilitated by...

Miniaturization of analytical instrumentation is paramount to enabling convenient in-field sensing. The recent thrust in potentiostat miniaturization for electrochemical sensing and general use has led the development commercial application specific integrated circuits (ASICs) that pack all power a benchtop instrument into one 5 mm × chip. While capabilities these far exceed those open-source potentiostats literature, activation barrier their implementation requires extensive electrical...

We demonstrate quantification of porosity, nanopore tortuosity, and electrical connectivity at the single-nanoparticle (NP) level for NPs synthesized by nanodroplet-mediated electrodeposition. Focused ion beam nanoslice tomography was used to slice with ca. 10 nm resolution followed imaging using scanning electron microscopy (SEM), allowing measurement these parameters on not amenable transmission microscopy. Slices were reconstructed in three dimensions revealed pores an average size 3 ± 2...

We present a robust and facile method to produce metal nanoparticle (NP) alloys in one-step synthesis using direct electrodeposition onto highly oriented pyrolytic graphite (HOPG). Precursor salts, H2PtCl6 Pd(NO3)2, were dissolved 1 mM sodium dodecylsulfate (SDS) water droplet with 1× phosphate buffered saline solution suspended dichloroethane (DCE) continuous phase. Tetrabutylammonium perchlorate was added the DCE phase maintain charge balance during electrodeposition. NP fabrication via...

The progression of nanoscience necessitates quantitative tools to understand reactivity at the nanoscale. Here, we report a model that describes both electrokinetic and diffusion-limited growth single nanoparticle (NP) within sub-femtoliter reactors apply quantify kinetics platinum NPs aqueous nanodroplets (rdrop ≈ 500 nm). time-resolved mechanism can be observed by studying collisions chloroplatinate-filled with ultramicroelectrodes (UMEs). If potential UME is biased sufficiently negative...

The interfacial properties of multiphase systems are often difficult to quantify. We describe the observation and quantification immiscible solvent entrapment on a carbonaceous electrode surface using microscopy-coupled electrogenerated chemiluminescence (ECL). As aqueous microdroplets suspended in 1,2-dichloroethane collide with glassy carbon surface, small volumes become entrapped between phase, resulting an overestimation true microdroplet/electrode contact area. To quantify contribution...

Molecularly imprinted polymers (MIPs) may be used to confer specific recognition properties a variety of practical sensors and sorbents. However, the synthetic parameters (monomer species, template/monomer ratio, etc.) generate MIPs significantly impact their sensitivity selectivity, generally requiring arduous empirical optimization obtain materials with maximal target affinity. We present MIP synthesis strategy that prioritizes pre-polymerization complex as predictive model for final...

Electrochemical measurements over an array of electrodes may be accomplished with one three potentiostat architectures: a single-channel device which averages the signal from number interconnected electrodes, multichannel dedicated circuits for each electrode, or multiplexer interface to isolate specific electrodes. Of these architectures, use is best suited facilitate individual without need large numbers channels. We present versatile strategy development flexible printed circuit (FPC)...

The ubiquitous Faraday cage, an experimental component particularly essential for nanoelectrochemical measurements, is responsible neutralizing noise introduced by electromagnetic interference (EMI). cage designs abound in the literature, often exhibiting varying thicknesses, mesh sizes, and base materials. fact that composition most goes unreported underscores many electrochemical researchers assume a 100% EMI reduction any given design. In this work, assumption challenged from theoretical...

Over 200 years ago, Alessandro Volta published his observations of a steady voltage when piece electrolyte-soaked cardboard was sandwiched between two dissimilar metals. This observation initiated century argument as to the origin voltaic electricity (contact vs chemical) and catalyzed practical advances, such first demonstration water electrolysis by William Nicholson Anthony Carlisle within few months Volta's announcement. A deep dive into literature demonstrates that practitioners at time...

Trace analysis of heavy metals in complex, environmentally relevant matrices remains a significant challenge for electrochemical sensors employing stripping voltammetry-based detection schemes. We present an alternative method capable selectively preconcentrating Cu2+ ions at the electrode surface using chelating polymer-wrapped multiwalled carbon nanotubes (MWCNTs). An sensor consisting poly-4-vinyl pyridine (P4VP)-wrapped MWCNTs anchored to poly(ethylene terephthalate) (PET)-modified gold...