Vacancy Engineering for Tuning Electron and Phonon Structures of Two‐Dimensional Materials

Abstract

2D inorganic materials are now breeding a wide‐ranging series of energy applications including catalysis, electrochemical activity, thermoelectricity and spin electronic devices. However, the physicochemical property of virgin 2D inorganic materials can scarcely satisfy the modern increasing diversificated demand of theory and applcations. In this regard, confined electron and phonon structures will be a directive for rationally tuning the intrinsic properties of 2D inorganic materials. Given this, vacancies in even infinitesimal concentrations could unlock the huge potential that exists for manipulating the energy band structure, carrier concentration, spin nature and phonon vibration and migration, which in turn will lead to the functionalization of intrinsic properties, particular in atom‐thick 2D solids. The concept of vacancy regulation embodies the design philosophy of “less is more”, and provides an opportunity to explore uncharted quantum phenomenon. In this review, recent progress in the design of appropriate vacancies on the 2D plane, particularly from the authors' own laboratories, is summarized, and the vacancy regulation rules of electron and phonon behavior are explained. Finally, based on an unambiguous understanding of the structure–property relationships between the vacancy, electron‐phonon behavior, and the intrinsic properties, future possibilities for the rational design of vacancies to acquire desirable properties are explored.

Boosting the Electrocatalytic Activity of Co3O4 Nanosheets for a Li-O2 Battery through Modulating Inner Oxygen Vacancy and Exterior Co3+/Co2+ Ratio

“…[8][9][10][11] Some previous studies have shown that the use of some suitable catalysts is one of the effective ways to reduce the overpotential of Li-air cells and extend the cycle life. [12][13] Noble metals (Au, Pt, Pd etc.)…”

Stepping towards Solar Water Splitting: Recent Progress in Bismuth Vanadate Photoanodes

“…Defect engineering, such as introduction of disorder and vacancy, can also be considered as a kind of self‐doping, which has been widely studied and reported in energy conversion applications . A typical case of defect doping is the hydrogenated treatment of TiO 2 to expand the photon absorption range from ultra‐violet to near‐infrared by creating a disordered surface and Ti 3+ self‐doping .…”

“…Defect engineering, such as introduction of disorder and vacancy, can also be considered as a kind of self-doping, which has been widely studied and reported in energy conversion applications. [89][90][91][92] A typical case of defect doping is the hydrogenated treatment of TiO 2 to expand the photon absorption range from ultra-violet to near-infrared by creating a disordered surface and Ti 3 + self-doping. [84][85][86] In general, an efficient photoanode consists of photo-responsive semiconductors and OER co-catalysts, implying that defect doping can be designed and tuned on either semiconductors or co-catalysts.…”

Photocatalytic Properties Dependent on the Interfacial Defects of Intergrains within TiO2 Mesocrystals

“…Therefore, it seems that defect engineering could be one of the best approaches to improve the photocatalytic performance of TiO 2 for use in environmental pollution remedies and solar energy conversion . Among all defects in TiO 2 , the oxygen vacancy (V O ) can be regarded as one of the most important and prevalent defects . Research indicates that surface V O s can act as vital absorption and active sites in photocatalysis, which can strongly influence the photocatalytic activity .…”

“…[5] Among all defects in TiO 2 ,t he oxygen vacancy (V O )c an be regarded as one of the most important and prevalentd efects. [6] Research indicates that surface V O sc an act as vital absorption anda ctives ites in photocatalysis, which can strongly influence the photocatalytica ctivity. [7] The V O sa re also the active sites for water dissociation on the rutile TiO 2 (110) surface.…”