Topological self-template directed synthesis of multi-shelled intermetallic NiGa hollow microspheres for the selective hydrogenation of alkyne.

Multi-shelled hollow structured materials featuring large void volumes and high specific surface areas are very promising for a variety of applications. However, controllable synthesis of multi-shelled hollow structured intermetallic compounds remains a formidable challenge due to the high annealing temperature commonly required for the formation of intermetallic phases. Here, a topological self-template strategy was developed to solve this problem. Using this strategy, we prepared well-defined multi-shelled intermetallic NiGa hollow microspheres (NiGa-MIHMs) as disclosed by the HAADF-STEM, HRTEM, and EDS characterizations, and the BET specific surface areas of them measured as much as 153.4 m g. XRD and EXAFS spectral characterizations revealed the atomically ordered intermetallic phase nature of the NiGa-MIHMs. The selective hydrogenation of acetylene catalytic evaluation results further demonstrated excellent catalytic properties of the NiGa-MIHMs, which results from the more energetically facile reaction pathway for acetylene hydrogenation and ethylene desorption over it as revealed by DFT calculations. Besides, this strategy is also extendable to synthesize other multi-shelled intermetallic NiSn hollow microspheres, and is expected to open up new opportunities for rational design and preparation of novel structured and highly efficient intermetallics.