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

Abstract

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.