RESUMEN
Renewable-driven electrocatalytic nitrate conversion offers a promising alternative to alleviate nitrate pollution and simultaneously harvest green ammonia. However, due to the complex proton-electron transfer processes, the reaction mechanism remains elusive, thereby limiting energy efficiency. Here, we adopt Ni(OH)2 as a model catalyst to investigate the dynamic evolution of the reaction interface. A proposed OH cycle mechanism involves the formation of a locally OH-enriched microenvironment to promote the hydrogenation process, which is identified through in-situ spectroscopy and isotopic labelling. By further activating the dynamic state through the implementation of surface vacancies via plasma, we achieve a high Faradaic efficiency of almost 100%. The activated interface accelerates the OH cycle by enhancing dehydroxylation, water dissociation, and OH adsorption, thereby promoting nitrate electroreduction and inhibiting hydrogen evolution. We anticipate that rational activation of the dynamic interfacial state can facilitate electrocatalytic interface activity and improve reaction efficiency.
RESUMEN
Retinal organoids (ROs) are a three-dimensional culture system mimicking human retinal features that have differentiated from induced pluripotent stem cells (iPSCs) under specific conditions. Synapse development and maturation in ROs have been studied immunocytochemically and functionally. However, the direct evidence of the synaptic contact ultrastructure is limited, containing both special ribbon synapses and conventional chemical synapses. Transmission electron microscopy (TEM) is characterized by high resolution and a respectable history elucidating retinal development and synapse maturation in humans and various species. It is a powerful tool to explore synaptic structure in ROs and is widely used in the research field of ROs. Therefore, to better explore the structure of RO synaptic contacts at the nanoscale and obtain high-quality microscopic evidence, we developed a simple and repeatable method of RO TEM sample preparation. This paper describes the protocol, reagents used, and detailed steps, including RO fixation preparation, post fixation, embedding, and visualization.