Water Splitting: Defect-Engineered Ultrathin δ-MnO2 Nanosheet Arrays as Bifunctional Electrodes for Efficient Overall Water Splitting (Adv. Energy Mater. 18/2017)

In article number 1700005, Fei Teng, Tierui Zhang, and co-workers report a noble-metal-free bifunctional electrode consisting of ultrathin manganese dioxide (δ-MnO2) nanosheet arrays on a nickel foam, exhibiting high performance for HER and OER. The remarkable overall water splitting activity is mainly attributed to the numerous active sites and excellent electrical conductivity of δ-MnO2 nanosheets, containing abundant oxygen vacancies and unsaturated Mn3+ sites due to the near monolayer thickness.