Graphical abstract New designed NiCo–Pt nanopolyhedrons inlay-structures, synthesized by galvanic replacement method, exhibit exceedingly high catalytic activity to dehydrogenation toward boron hydride under moderate conditions due to the cooperation of high proportional active crystal surface and inlay-heterostructures. This excellent function empowers the potential of the product for its possible application on energy source and chemical industry. Highlights ► New designed NiCo–Pt nanopolyhedron inlay-structures have been firstly reported in this work. ► NiCo–Pt hexagonal-nanoplates exhibit exceedingly high dehydrogenation catalytic activity. ► NiCo–Pt magnetic nanopolyhedrons can be separated and recovered for recyclable use. ► As-obtained NiCo–Pt nanopolyhedrons have the potential application in energy source.