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Nanoparticles are an indispensable part of our lives. From electronic devices to drug delivery to catalysis and energy storage, nanoparticles have found various important applications. Out of the many synthetic strategies to generate nanoparticles, electrodeposition has stood out due to its cost effectiveness, low time consumption and simplicity. However, traditional electrodeposition techniques have suffered from controlling the size, shape, morphology and microstructure of nanoparticles. Here, we use a technique called nanodroplet‐mediated electrodeposition, where nanodroplets carrying the metal salt precursor collide with a negatively‐biased electrode. In this work, we use this nanodroplet‐mediated electrodeposition technique along with transmission electron microscopy, selected‐area electron diffraction and high‐angle‐annular dark‐field scanning transmission electron microscopy to show control over the microstructure of single nanoparticles. Along with that, we use X‐ray photoelectron spectroscopy to get mechanistic insights behind the alteration of microstructure observed. Having achieved a control over the microstructure, we show the application by synthesising polycrystalline alloys at room temperature and evaluating the electrocatalytic behavior of the different microstructures towards the hydrogen evolution reaction. This fundamental work of controlling microstructures of single nanoparticles and its applications in alloy synthesis and electrocatalysis opens a new avenue of tuning nanoparticles for various applications. 

Triple-barrel electrodes can monitor temperature and freezing events in microdroplets in real time, delivering enhanced temporal resolution and standalone insights into the ice nucleation and the thermoelectrochemical properties of aqueous systems. 

The curious chemistry observed in microdroplets has captivated chemists in recent years and has led to an investigation into their ability to drive seemingly impossible chemistries. One particularly interesting capability of these microdroplets is their ability to accelerate reactions by several orders of magnitude. While there have been many investigations into which reactions can be accelerated by confinement within microdroplets, no study has directly compared reaction acceleration at the liquid|liquid and gas|liquid interfaces. Here, we confine glucose oxidase, one of life’s most important enzymes, to microdroplets and monitor the turnover rate of glucose by the electroactive cofactor, hexacyanoferrate (III). We use stochastic electrochemistry to monitor the collision of single femtoliter water droplets on an ultramicroelectrode. We also develop a measurement modality to robustly quantify reaction rates for femtoliter liquid aerosol droplets, where the majority of the interface is gas|liquid. We demonstrate that the gas|liquid interface accelerates enzyme turnover by over an order of magnitude over the liquid|liquid interface. This is the first apples-to-apples comparison of reaction acceleration at two distinct interfaces that indicates that the gas|liquid interface plays a central role in driving curious chemistry. 

Abstract The commercialization of zinc metal batteries (ZMBs) for large‐scale energy storage is hindered by challenges such as dendrite formation, the hydrogen evolution reaction (HER), and passivation/corrosion, which lead to poor stability of zinc metal anodes. HER is a primary contributor to this instability, and despite efforts to enhance ZMB cyclability, a significant knowledge gap remains regarding the origin of HER in these systems. Prior works, based primarily on theoretical calculations with minimal experimental support, suggest that HER originates from Zn²⁺‐solvated water. For the first time, by employing scanning electrochemical microscopy (SECM), and electrochemical mass spectrometry (ECMS), in real‐time the inherently intertwined nature of Zn electrodeposition and H₂ liberation is revealed, both exhibiting the same onset potential in voltammetry. The findings show that water molecules surrounding Zn²⁺ ions undergo reduction simultaneously during Zn²⁺ deposition. Additionally, ECMS conducted under chronopotentiometric/galvanostatic conditions at battery‐relevant current densities elucidates why elevated electrolyte concentrations enhance the prolonged cyclability of ZMBs. Understanding the origin of HER opens avenues for developing high‐performance, reliable aqueous ZMBs, addressing key challenges in their commercialization and advancing their technological capabilities.