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

Abstract

Photocatalytic (PC) and photoelectrochemical (PEC) water splitting is a plethora of green technological process, which transforms copiously available photon energy into valuable chemical energy. With the augmentation of modern civilization, developmental process of novel semiconductor photocatalysts proceeded at a sweltering rate, but the overall energy conversion efficiency of semiconductor photocatalysts in PC/PEC is moderately poor owing to the instability ariseing from the photocorrosion and messy charge configuration. Particularly, layered double hydroxides (LDHs) as reassuring multifunctional photocatalysts, turned out to be intensively investigated owing to the lamellar structure and exceptional physico‐chemical properties. However, major drawbacks of LDHs material are its low conductivity, sluggish mass transfer and structural instability in acidic media, which hinder their applicability and stability. To surmount these obstacles, the formation of LDH@graphene and analogus heterostructures could proficiently amalgamate multi‐functionalities, compensate distinct shortcomings, and endow novel properties, which ensure effective charge separation to result in stability and superior catalytic activities. Herein, we aim to summarize the currently updated synthetic strategies used to design heterostructures of 2D LDHs with 2D/3D graphene and graphene analogus material as graphitic carbon nitride (g‐C3N4), and MoS2 as mediator, or interlayer support, or co‐catalyst or vice versa for superior PC/PEC water splitting activities along with long‐term stabilities. Furthermore, latest characterization technique measuring the stability along with variant interface mode for imparting charge separation in LDH@graphene and graphene analogus heterostructure has been identified in this field of research with understanding the intrinsic structural features and activities.

Superlative photoelectrochemical properties of 3D MgCr-LDH nanoparticles influencing towards photoinduced water splitting reactions

“…However, the slow OER kinetics, including the 4 electron transfer to form O 2 requires a potentate catalyst, which could minimize the overpotentials required in water splitting 9 , 10 . Since from the foremost invention of PEC water splitting on TiO 2 photoelectrode by Fujishima and Honda 11 , diverse low-cost, abundant and renewable photocatalytic materials such as Bi 2 WO 6 12 , 13 , g-C 3 N 4 14 – 18 , CdS 19 , 20 , MoS 2 21 , 22 , graphene 22 – 24 , MXene 25 – 27 , graphdiyne 28 , etc., have been developed for their sustainability, suitability and efficiency for water splitting reactions. In addition, recently CoWO 4 nanocubes 29 , CuWO 4 nanoparticles (NP) 30 , α-Fe 2 O 3 @g-C 3 N 4 31 , Ni/MoO 2 @N-doped-carbon 32 , NiMoO 4 -nanorods@rGO 33 , and CuWO 4 @rGO 34 , electrode materials have been developed, which could be regarded as highly effective in water electrolysis reaction 35 .…”

Review on the Application of Semiconductor Heterostructures in Photocatalytic Hydrogen Evolution: State-of-the-Art and Outlook

“…91,104 Combining different semiconductor photocatalytic materials with LDHs to construct heterostructures is a conventional and promising method to improve the photocatalytic performance of composites. 105,106 2.4.1. NiFe-LDH/Zn 0.5 Cd 0.5 S. CdS is empolyed in photocatalytic hydrogen production mostly because it possesses a narrow band gap and can absorb a wide range of visible light.…”

Graphene-Based Derivatives Heterostructured Catalytic Systems for Sustainable Hydrogen Energy via Overall Water Splitting

“…At the time of PEC operation, when the catalytic system is irradiated, the photo-generation of the charge carriers takes place at the semiconducting base, where graphene-based derivatives participate in the process of charge transfer. The major part of the graphene in the binary/ternary heterostructures is to serve as a transporter, electron acceptor and mediator, having a 2D conductive structure [193][194][195][196][197][198][199][200]. Graphene, owing to its unique layered structure, accelerates the electron-hole segregation and transport of electrons in distinct photo-electrodes.…”