Sponges are the simplest multicellular animals in the world,which have bodies full of pores and channels allowing water to circulate through them.Likewise,the three dimensional(3D)porous structures play critical roles in many chemical reactions.Inspired by nature,assembling inorganic nanoparticles(NPs)into such macroscopic sponge-like 3D architectures is an important bottom-up strategy in nano-research,bridging the gap between individual NPs and the structures intended for practical applications.The resultant structure usually exhibit hierarchical structures with controlled crystallinity and composition,which can afford the chemical and physical features of NPs in addition to typical properties of macro porous materials,and often integrate various properties in one material.