Recent Progress on Nanostructured Layered Double Hydroxides for Visible‐Light‐Induced Photoreduction of CO₂

Abstract

Photoreduction of CO 2 into solar fuels is usually regarded as one of the promising solutions to overcome environmental pollution and the energy crisis. The main challenge in CO 2 photoreduction (CO 2 PR) is the low efficiency and poor selectivity. Layered double hydroxides (LDHs) are a class of 2D materials, consisting with M(OH) 6 octahedra in the host layers and intercalated anions. Owing to the tuneable composition, particle size, morphology, and virtue coordinatively unsaturated active sites, a series of efficient strategies (morphology control, heterostructure, defect control, etc.) in LDH-based photocatalysts have been efficiently developed to enhance the photocatalytic selectivity and activity for CO 2 PR. This review summarizes recent progress on the LDH-based photocatalysts for CO 2 PR. Al 3 + and transition metal elements, Fe 2 + , Co 2 + , Ni 2 + , Zn 2 + , Cr 3 + , Fe 3 + , etc.) in the laminate layers and A nÀ is the interlaminated anion (such as: NO 3 À , CO 3 2À and SO 4 2À , etc.) in the interlayer. [6b,c,7] It has been widely applied in photocatalyst in the past decades. [8] Ascribe to the tunable atomic structure, the bandgap of LDHs can be tuned from 2.0 eV to 5.4 eV by changing the composition of layer. [9] Moreover, the surface defects (such as: V M , metal vacancy and V OH , hydroxyl vacancy, etc.) as active sites in photocatalysis can be easily introduced by controlling the thickness and size of LDHs etc., thus promoting the efficiency of CO 2 PR. This review focuses on the recent development of the LDHs-based photocatalysts for CO 2 PR, and the corresponding progress of CO 2 PR has achieved great progress from the former CO 2 conversion rate of~1 μmol g À 1 h À 1 to recent 218130 μmol g À 1 h À 1 , and the desirable valuable-product also move from CO to CH 4 and methanol. The major strategies of promoting the CO 2 PR are discussed from different perspective from the morphology and composition, electronic structure, and defects structure for further understanding the relationship between the structure and activity.

In Situ Growth of ZnIn2S4 on MOF-Derived Ni–Fe LDH to Construct Ternary-Shelled Nanotubes for Efficient Photocatalytic Hydrogen Evolution

“…Layered double hydroxides (LDHs) are regarded as one of the most promising photocatalysts due to the high layer charge density and advantageous 2D structure. , Among the reported LDHs, Ni–Fe LDHs have emerged as an ideal candidate for photocatalytic hydrogen evolution, owing to the synergistic effect between Ni and Fe species. , Ni–Fe LDH nanotubes are desirable for photocatalytic water splitting due to their high specific surface area, excellent electrical conductivity, and exposed active sites. Ni–Fe LDH with a double-shelled hollow structure possesses larger inner space and makes other semiconductors easy to disperse and stabilize in comparison with a single-shelled structure.…”

Recent Progress in LDH@Graphene and Analogous Heterostructures for Highly Active and Stable Photocatalytic and Photoelectrochemical Water Splitting

“…From the above discussion relevant to the structure and properties of LDHs, it is worth to be mentioned that LDHs have wide applications in broad areas of research such as in PC water splitting, [111–115] PEC water splitting, [116] CO 2 reduction, [117,118] NO x reduction, [119] electrochemical oxidation, [120,121] magnetisation, [122] catalytic ozonation process, [123] and fillers in polymers, [124] etc. This is, assured to mainly the following distinctive features of LDHs: (i) enriched surface hydroxyl groups with interesting properties of swelling nature and oxo‐bridged bimetallic linkage; (ii) the nature of anions with interlayer spaces; (iii) high redox properties with hierarchical morphologies and chemical stability; and (iv) the reconstruction or memory effect.…”

COF‐5/CoAl‐LDH Nanocomposite Heterojunction for Enhanced Visible‐Light‐Driven CO2 Reduction

“…[22] However, the fast recombination of the photoinduced carriers and the relatively low specific surface area of LDHs in the layered materials severely restrict their further application. [23] Lately, CoAl-LDH has been integrated with UV-active photocatalysts materials, such as g-C 3 N 4 and TiO 2 , which fully investigates the construction of the structured heterojunction with the significantly enhanced catalytic performance for photocatalytic CO 2 reduction. [24] Khan and Tahir have successfully prepared a highly active ternary CoAlLa-LDH by properly weaving lanthanum into the framework of LDH, which greatly improves the coordinatively unsaturated metal centers for the development of reductive sites and accelerates the separation of the photogenerated charge carriers.…”

“…Especially, LDHs possess the adjustable bandgap (spanning the UV to visible region), and their alkaline OH groups are conducive to the adsorption and activation of CO 2 molecules in the photocatalytic process [22] . However, the fast recombination of the photoinduced carriers and the relatively low specific surface area of LDHs in the layered materials severely restrict their further application [23] . Lately, CoAl‐LDH has been integrated with UV‐active photocatalysts materials, such as g‐C 3 N 4 and TiO 2 , which fully investigates the construction of the structured heterojunction with the significantly enhanced catalytic performance for photocatalytic CO 2 reduction [24] .…”