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Regulating the coordination environment of atomically dispersed catalysts is vital for catalytic reaction but still remains a challenge. Herein, an ionic exchange strategy is developed to fabricate atomically dispersed copper (Cu) catalysts with controllable coordination structure. In this process, the adsorbed Cu ions exchange with Zn nodes in ZIF‐8 under high temperature, resulting in the trapping of Cu atoms within the cavities of the metal−organic framework, and thus forming Cu single‐atom catalysts. More importantly, altering pyrolysis temperature can effectively control the structure of active metal center at atomic level. Specifically, higher treatment temperature (900 °C) leads to unsaturated Cu–nitrogen architecture (CuN3 moieties) in atomically dispersed Cu catalysts. Electrochemical test indicates atomically dispersed Cu catalysts with CuN3 moieties possess superior oxygen reduction reaction performance than that with higher Cu–nitrogen coordination number (CuN4 moieties), with a higher half‐wave potential of 180 mV and the 10 times turnover frequency than that of CuN4. Density functional theory calculation analysis further shows that the low N coordination number of Cu single‐atom catalysts (CuN3) is favorable for the formation of O2* intermediate, and thus boosts the oxygen reduction reaction.

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We report the controlled synthesis of four kinds of cobalt basic salts with different morphologies and colors (pink, blue, green, and lavender) using urea as a hydrolysis agent in the presence of block copolymer P123. Li 2 SO 4 and LiCl were used as salt additives to control the type of cobalt basic salts. It was found that the amount of urea plays a critical role in the synthesis of cobalt basic salts with different phases. Two of them exhibit interesting three-dimensional urchinlike and flowerlike morphology assembled from nanorods (pink) and nanosheets (blue), respectively. The present work suggests that it is possible to directly grow threedimensional-ordered assemblies built from one-dimensional or two-dimensional cobalt basic salt nanostructures through a one-step aqueous solution-phase chemical route under controlled conditions.