Adsorption Energy in Oxygen Electrocatalysis

Adsorption energy (AE) of reactive intermediate is currently the most important descriptor for electrochemical reactions (e.g., water electrolysis, hydrogen fuel cell, electrochemical nitrogen fixation, electrochemical carbon dioxide reduction, etc.), which can bridge the gap between catalyst's structure and activity. Tracing the history and evolution of AE can help to understand electrocatalysis and design optimal electrocatalysts. Focusing on oxygen electrocatalysis, this review aims to provide a comprehensive introduction on how AE is selected as the activity descriptor, the intrinsic and empirical relationships related to AE, how AE links the structure and electrocatalytic performance, the approaches to obtain AE, the strategies to improve catalytic activity by modulating AE, the extrinsic influences on AE from the environment, and the methods in circumventing linear scaling relations of AE. An outlook is provided at the end with emphasis on possible future investigation related to the obstacles existing between adsorption energy and electrocatalytic performance.

Engineering of core−shell Au nanorods@ZIF−8 electrocatalyst for sensitive voltammetric determination of 2−chlorophenol in aquaculture

Herein, polyvinylpyrrolidone−stabilized Au nanorods were controllably implanted into ZIF−8 to form well−uniformed AuNRs@ZIF−8 electrocatalyst with multicore−shell structure. After characterizing the chemical and physical properties, a novel electrochemical sensing platform was fabricated for 2−chlorophenol (2−CP) monitoring based on the AuNRs@ZIF−8 modified glassy carbon electrode. Due to the unique electrochemical property of AuNRs cores and ultra−porous architecture of ZIF−8 shell, the electrocatalyst would effectively accelerate the electron transfer and greatly improve the electrochemical response of 2−CP. Under the optimized experimental conditions, the oxidation peak current of 2−CP enhanced linearly with the increase of its concentration between 0.010 and 40 μM, and the limit of detection was 3.6 nM based on S/N = 3. Meanwhile, the prepared AuNRs@ZIF−8 electrode showed favorable stability, reproducibility, and selectivity, which could be applied to the accurate analysis of 2−CP in aquaculture with standard addition recovery ranging from 96.67% to 104.0%.

Investigation of antisolvent effect on gold nanoparticles during postsynthesis purification

Gold nanoparticles (Au NPs) were synthesized by reducing HAuCl₄ using borane tert-butylamine complex in the presence of alkylamine (dodecylamine, hexadecylamine, and octadecylamine) and didodecyldimethylammonium bromide. Ethanol was used as an antisolvent for the postsynthesis purification of Au NPs. Au NPs had uniform size distribution after first wash with ethanol and the aggregation and growth of Au NPs happened after second wash with ethanol. The Au NPs were characterized by TEM, SEM, XRD, ¹H NMR, UV-vis absorption and FTIR spectroscopy. The aggregated mechanism after the second wash with ethanol was proposed. Au NPs still retained their monodispersity after second wash compared with after first wash using the antisolvents, such as acetonitrile, dimethyl sulfoxide and acetone. The presented results suggest that the good choice of antisolvent is critical for the postsynthesis purification of Au NPs.