The electroreduction of nitrate offers a promising, sustainable, and decentralized route to generate valuable ammonia. However, a key challenge in the nitrate reduction reaction is the energy efficiency of the reaction, which requires both a high ammonia yield rate and a high Faradaic efficiency of ammonia at a low working potential (≥−0.2 V versus reversible hydrogen electrode). We propose a bimetallic Co–B/Ru₁₂ electrocatalyst which utilizes complementary effects of Co–B and Ru to modulate the quantity of adsorbed hydrogen and to favor the specific hydrogenation for initiating nitrate reduction reaction at a low overpotential. This effect enables the catalyst to achieve a Faradaic efficiency for ammonia of 90.4 ± 9.2% and a remarkable half-cell energy efficiency of 40.9 ± 4% at 0 V versus reversible hydrogen electrode. The in-situ electrochemical reconstruction of the catalyst contributes to boosting the ammonia yield rate to a high level of 15.0 ± 0.7 mg h⁻¹ cm⁻² at −0.2 V versus reversible hydrogen electrode. More importantly, by employing single-entity electrochemistry coupled with identical location transmission electron microscopy, we gain systematic insights into the correlation between the increase in the catalyst’s active sites and its structural transformations during the nitrate reduction reaction.

High‐entropy alloys (HEAs), especially in the form of compositional complex solid solutions (CCSS), have gained attention in the field of electrocatalysis. However, exploring their vast composition space concerning their electrocatalytic properties imposes significant challenges. Scanning electrochemical cell microscopy (SECCM) offers high‐speed electrochemical analysis on surface areas with a lateral resolution down to tens of nm. However, high‐precision piezo positioners often used for the motion of the tip limit the area of SECCM scans to the motion range of the piezo positioners which is typically a few tens of microns. To bridge this experimental gap, the study proposes a long‐range SECCM system with a rapid gas‐exchange environmental cell for high‐throughput electrochemical characterization of 100 mm diameter HEA thin‐film material libraries (ML) obtained by combinatorial co‐sputtering. Due to the gas–liquid interface at the positioned SECCM droplet on the sample, high‐throughput evaluation under industrial current density conditions becomes feasible. This allows the direct correlation between electrocatalytic activity and material composition with high statistical reliability. The multidimensional data obtained accelerates materials discovery, development, and optimization.

Scanning electrochemical microscopy (SECM) and scanning electrochemical cell microscopy (SECCM) were integrated in a single bifunctional probe for simultaneous mapping of the oxygen reduction current and the oxidation current of the produced H₂O₂. The dual probe is fabricated from a double-barrel θ capillary, comprising one open barrel filled with the electrolyte and another filled with pyrolytic carbon. Pt is deposited with a gas injection system (GIS) at the end of the carbon barrel. The probe integrates the advantages of both SECM and SECCM by forming an electrochemical droplet cell that embeds the Pt working electrode of the carbon barrel directly into the electrolyte meniscus formed upon sample contact from the electrolyte barrel. The versatility of the dual probe is demonstrated by mapping the oxygen reduction reaction (ORR) current and the H₂O₂ oxidation current of a Pt microstrip on a gold substrate. This allows simultaneous localized electrochemical measurements, highlighting the potential of the dual probe for broader applications in characterizing the electrocatalytic properties of materials.

In this study, the modification of glassy carbon electrodes by potentiostatic pulsed deposition of platinum nanoparticles and potentiostatic pulsed polymerization of polyaniline nanofibers was investigated. During the preparation of the nano-composite materials, the control of the potentiostatic pulsed deposition and potentiostatic pulsed polymerization parameters, such as pulse potential, pulse width time, duty cycle, and platinum precursor concentration allowed the optimization of the size, shape, and distribution of the deposited Pt nanoparticles. It is noteworthy that the polymerization method, cyclic voltammetry method, or potentiostatic pulsed polymerization method show an important effect in the morphology of the deposited polyaniline (PANI) film. The obtained modified electrodes, with highly uniform and well dispersed platinum nanoparticles, exhibit good electrocatalytic properties towards methanol oxidation.

Metal–organic frameworks (MOFs) are considered promising electrocatalytic materials due to their adjustable coordination bonds between metal ions and organic ligands. The abundance of metal centers within MOFs offers potential active sites. However, the limited availability of adsorption sites in the case of fully coordinated metal ions might lead to insufficient electrocatalytic activity. The selectivity is tuned during the electrochemical CO ₂ reduction reaction (eCO ₂ RR) using Cu‐1H‐1,2,3‐triazole MOF from C ₁ products to C ₂₊ products by generating defects to enable a local increase in CO ^* coverage, thus improving eCO ₂ RR performance. The catalyst exhibits ≈78.4% of total Faradaic efficiency for C ₂₊ products at −200 mA cm ⁻² current density in 1.0 m KOH as electrolyte.