Vacancy in Ultrathin 2D Nanomaterials toward Sustainable Energy Application

Abstract

The unique physicochemical properties of (2D) nanomaterials make them well‐suited for use in sustainable energy applications. Many of these materials can be further improved with vacancy engineering. This review details recent progress in the vacancy engineering of ultrathin 2D nanomaterials. For clarity, it mainly focuses on various ultrathin 2D materials in three categories: Xa&XaYb‐, MaXb‐, or MaXbYc‐structured materials. Recently developed vacancies in different types of ultrathin 2D materials, as well as their preparation and characterization, are described. Emphasis is placed on the potential electrochemical energy storage and conversion applications of these materials. This review considers the relationship between vacancy properties and material categories of various ultrathin 2D materials in terms of application requirements, preparation, and characterization techniques. The challenges and future outlook of this promising field are summarized.

Boosting Electrocatalytic Water Oxidation by Creating Defects and Lattice‐Oxygen Active Sites on Ni‐Fe Nanosheets

“…Defect or vacancy control is a particularly attractive means of modifying the properties of ultrathin 2D nanomaterials . Under oxidative conditions, the doped TM ions in TM‐NiFe could be oxidized and removed, leaving defects on the nanosheets (Figure c,d).…”

“…In recent years, tremendous efforts have been devoted to exploiting non‐noble‐metal‐based OER catalysts . Among them, Ni−Fe layered‐double‐hydroxides (LDHs) are the most attractive candidates, owing to their state‐of‐the‐art OER performance, tunability, and potential stability in alkaline conditions. To date, they have been applied in advanced hydrothermal synthesis, electrosynthesis, and hybrid approaches with excellent results .…”

“…Ni−Fe LDH structures are characterized by stratified nanosheets, the structural −OH groups of which complicate the metal centers as the catalytic sites. The introduction of defects on the nanosheets is a particularly attractive method for tailoring the electronic properties and chemical composition of such systems, which can potentially lead to an enhancement of the catalytic OER performance …”

Photocatalytic Advanced Oxidation Processes for Water Treatment: Recent Advances and Perspective

“…Various defects may bring disadvantages, but can also be exploited to improve a photocatalyst. At present, a large number of studies have extensively explored surface defects such as vacancies, [70] structural distortion, functional modification and hybrid hetero-structures, providing clear structural performance relations. Defects are used to regulate and promote photocatalyst light absorption, charge separation and transfer, and surface redox reactions.…”

Recent progress of defect chemistry on 2D materials for advanced battery anodes

“…* Vacancies: Proceeding from the vacancies, being the most investigated 0D-defects in 2D materials. [8,11,[37][38][39][40] They can be occur accidentally during preparation processes or voluntarily through processing. Such defects are formed during molecular statics and dynamics simulations through the stripping of atoms from the 2D structure.…”