Perovskite oxides are significant candidates to develop electrochemical catalysts for water oxidation in consideration of their high catalysis capacity,low costing and excellent stability.Rational design of coordination structure and overcoming poor electronic transport are regarded as critical factors for outstanding perovskite-based oxygen evolution reaction (OER) catalysts.Herein,we report a mild chemical oxidation method to realize ligancy engineering from strongly-correlated brownmillerite Sr2Co2O5 to perovskite phase Sr2Co2O5.5,along with abundant oxygen vacancies formation and greatly boosted electric conductivity,which helps to form the active species of Co hydroxide/oxide on the surface of catalysts.The coupling effect of catalytic kinetics and unimpeded electronic movement brings high OER activities in Sr2Co2O5.5 with a low onset potential and a small Tafel slope.Our work not only displays in-depth understanding into the relationship among catalysis performance and multiple physical degrees of freedom,but also paves a new path to develop high-efficient electrochemical catalysts.
The nitrile functionality is a key building block in synthetic chemistry, and has wide applications in pharmaceuticals. However, traditional methodologies for the synthesis of nitriles are limited to harsh reaction conditions. Herein, we report a new and efficient access to aryl nitriles by an electrochemical synthesis. Compared with the conventional synthetic methods, this electrochemical synthesis is more environmentally friendly and easier to handle.
Jia-Qian YeZhen-Lei ZhangZheng-Gen ZhaZhi-Yong Wang
β-Keto acids are unstable to heat,acids,and bases,and have rarely been employed as carbon nucleophiles for the formation of carbon-carbon bonds.In this context,an efficient decarboxylative alkylation reaction of β-keto acids with benzylic alcohols has been developed,for the first time,through sequential cleavage of carbon-oxygen and carbon-carbon bonds.In the presence of 10 mol% of ferric chloride,a range of β-keto acids smoothly undergo decarboxylative alkylation with benzylic alcohols to give structurally diverse unsymmetric ketones in moderate to excellent yields and with extremely high regioselectivity.Preliminary mechanistic studies indicate that the reaction proceeds through an SN1 alkylation followed by decarboxylation.
