2D hydrated layered Ni(OH)2 structure with hollow TiO2 nanocomposite directed chromogenic and catalysis capabilities

Two-dimensional (2D) hydrated layered structures have emerged as a fascinating new class of materials for diversified surface mediated redox reactions. Here, a solution-processable 2D hydrated layered structure, Ni(OH)(2) nanosheets with hollow TiO2 nanosphere composite has been designed to realize complementary electrochemical and catalysis reactions. The inherent 2D anisotropic lamellar hydrated framework of Ni(OH)(2) contains interstitial spaces to promote efficient and reversible insertion/extraction of electrolyte ions without compromising its structural integrity. This translates to a fast switching speed and high stability valence change of metal ions that actively tunes the optical transmittance. Additionally, the Ni(OH)(2) nanosheets synergistically play a co-catalyst role to enhance the photocatalytic degradation reactivity of TiO2 nanospheres. Correspondingly, the TiO2 nanospheres are composed of a porous thin shell that provides abundant active sites, distinct cavity diameter with enhanced light harvesting and improved reactant accessibility with a porous framework. Collectively, the nanocomposite is devised to exemplify a monolithically integrated multiple functionalities material system that unprecedentedly delivers photocatalytic degradation coupled electrochromism for environmental and energy conservations.