Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

Abstract

Inorganic 2D nanosheets are important building blocks for synthesizing efficient hybrid photocatalysts because of their advantageous characteristics such as highly anisotropic 2D morphology with subnanometer-level thickness, wide surface area, defect-free tunable surface, chemical composition diversity and crystal structure, and tailorable physicochemical properties. Since most of the components in exfoliated nanosheets are exposed on the surface, an unusually strong chemical interaction and a remarkable electronic coupling can occur in the interface between the exfoliated nanosheets and hybridized nanospecies. Such strong electronic coupling is useful in optimizing the photocatalytic activity of the hybrid material via the suppression of electron-hole recombination, increase of the light absorption region, improved transport of excited charge carriers, and increase of surface reactivity. Herein, several representative examples of inorganic 2D nanosheetbased hybrid photocatalysts are introduced to examine the crucial role of 2D nanosheets in the enhancement of the photocatalytic activity of the hybrid materials. Special emphasis is made regarding the unique hybridization effect of exfoliated 2D nanosheets on the optical properties and electron structure of semiconducting species. Future perspectives for the investigation of the 2D nanosheet-based hybrids are discussed to provide valuable insight for the design and synthesis of highly efficient photocatalysts for producing solar fuels.

2D Titanium/Niobium Metal Oxide‐Based Materials for Photocatalytic Application

“…Considering the features of a large specific surface area, atomic thickness, a high ratio of surfaced atoms, and intrinsic quantum confined electrons, the ultrathin NSs display such unusual properties as a tunable energy band structure, electronic anisotropy, and a high surface activity . As a consequence, the ultrathin NSs have been regarded as an effective way to advance the photocatalytic performance by optimizing the specific surface area and thus improving charge migration …”

Molecular‐Level Control of the Intersheet Distance and Electronic Coupling between 2D Semiconducting and Metallic Nanosheets: Establishing Design Rules for High‐Performance Hybrid Photocatalysts

“…Semiconductor‐assisted photocatalysis has received significant attention because of its effectiveness in converting solar energy into user‐friendly chemical energy. [ 1,2 ] The development of economically‐feasible high‐performance photocatalyst is indispensable for the industrial commercialization of solar energy‐based technologies such as the photosplitting of water into H 2 and O 2 , the photoconversion of CO 2 into valuable organics, and the environmental sanitization of harmful chemical species. [ 2–4 ] To explore efficient photocatalysts, diverse methodologies have been exploited, such as chemical substitution, facet control, hybridization, surface modification, and defect formation.…”

“…[ 1,2 ] The development of economically‐feasible high‐performance photocatalyst is indispensable for the industrial commercialization of solar energy‐based technologies such as the photosplitting of water into H 2 and O 2 , the photoconversion of CO 2 into valuable organics, and the environmental sanitization of harmful chemical species. [ 2–4 ] To explore efficient photocatalysts, diverse methodologies have been exploited, such as chemical substitution, facet control, hybridization, surface modification, and defect formation. [ 5 ] As one of the most effective synthetic strategies, hybridization with conductive nanospecies has been widely applied for a variety of photocatalyst materials.…”

Visible Light–Initiated Synergistic/Cascade Reactions over Metal–Organic Frameworks

“…Photocatalysis can utilize light, in particular the abundant and ubiquitous solar light, for production of clean fuels, environmental remediation, and green syntheses, and is therefore believed to be one of the most ideal ways for dealing with the current worldwide energy shortage and environmental pollution. [ 6–26 ] The use of light to initiate chemical reactions is traditionally realized only at an elevated temperature, and is considered to be sustainable and green, because it not only reduces energy consumption, but also diminishes the detrimental environmental impact associated with the chemical industries. [ 27–29 ] Light‐induced reactions are initially conducted via photochemical processes, in which the substrates are excited from their ground states to their electronically excited states after absorption of light.…”