Synthesis of Selenized Metal–Organic Framework Hollow Cage under Ambient Condition for Clean Energy Applications

The synthesis of structured metal organic framework (MOF)-derived selenide composites is a vibrantly emerging research area serving clean energy purposes. However, there is no way to convert MOFs into structured selenide composites under ambient conditions for unknown reasons. This work gave mechanistic insights into how the redox properties and release rate of selenium precursors influenced the structural inheritance behavior of MOFs during the selenization process, explaining why maintaining the morphology of MOFs during a room-temperature aqueous selenization process is a tricky task. A novel method of selenizing structured ZIF-67 into CoSex hollow cages with its cubic morphology maintained was developed. The target combination between Co and Se was the primary mechanism accounting for ZIF-67 selenization and its morphology inheritance. The selenized ZIF-67 was used in two typical clean energy areas, i.e., coal combustion detoxification and renewable energy storage. The performances of selenized ZIF-67 surpassed those of unstructured cobalt selenides and other benchmark materials used in these two areas. Following the mechanistic insights into the selenization process of ZIF-67, further work may develop more efficient methods to synthesize MOF-derived metal selenide composites under mild conditions, which is critical to extend the variety of MOF-derived materials and serve their cost-effective uses under practical scenarios.