ABSTRACT
Metal-organic frameworks (MOFs) have been increasingly popular in photocatalytic water-splitting research areas due to their unique, tunable porosity, high stability, large surface activity, and manipulative topology. However, the incapability of MOFs in harvesting broad-solar irradiation and rapid electron-hole pairs recombination has limited their efficiency in practical applications, and their structures allow researchers to manipulate them toward better efficiency. Also, linker modification is achieved by reclaiming the organic linker, which constructs MOFs by functionalizing, changing the ligand’s length, and using an aided organic linker. In addition, being a free space in their structure gives this opportunity to modify them easily with other compounds such as inorganic complex compounds and nanoparticles by incorporation, impregnation, and ship-in-a-bottle methods. The objectives of this review article are three-fold. First, to emphasize understanding of the fundamental correlation among promising strategies to improve the optoelectronic properties of MOFs such as light-harvesting capability and photoinduced electron-hole pairs for photocatalytic reactions involving water splitting reaction under broad solar irradiation. Second, to systematically summarize the organic linker modification and incorporation of polyoxometalate, coordination metal complexes, and various nanoparticles. Third, to discuss challenges and future research directions for the development of broad solar band activation of MOFs for photocatalysis purposes.
Summary
Investigation of the different methods for modification of MOFs
Review of the incorporation of complex compounds into MOFs in detail
Investigation of all the strategies for incorporation of complex compounds into MOFs
Abbreviation used
PWS | = | Photocatalytic Water Splitting |
STH | = | solar-to-hydrogen |
MOFs | = | Metal Organic Frameworks |
VB | = | Valence band |
CB | = | Conduction band |
HER | = | hydrogen evolution reaction |
NHE | = | Normal hydrogen electrode |
OER | = | oxygen evolution reaction |
LMCT | = | ligand to metal charge transfer |
LCCT | = | the linker‐to metal cluster charge transfer |
POM | = | polyoxometalate |
OMC | = | Organic-Metal Compounds |
NPs | = | nanoparticles |
Eg | = | Energy band gap |
OMC@MOFs | = | Incorporation of organic-metal compounds with metal organic frameworks |
NPs@MOFs | = | Incorporation of nanoparticles with metal organic frameworks |
ORR | = | oxygen reduction reaction |
MLCT | = | Metal ligand charge transfer |
LSPR | = | localized surface plasmon resonance |
HOCO | = | highest occupied crystal orbital |
LUCO | = | lowest unoccupied crystal orbital |
NB | = | None bond |
PCLEF | = | plasmonic concentrated local electromagnetic field |
CDs | = | Carbon nanodots |
LLES | = | the low-lying excited states |
MLCT | = | metal-to-ligand charge-transfer |
LC | = | ligand-centered |
MC | = | metal-centered |
PL | = | photo-luminescent |
PEC | = | photoelectrochemical |
CPs | = | Coordination polymers |
HOMO | = | Highest occupied molecular orbital |
LUMO | = | Lowest unoccupied molecular orbital |
HSAB | = | Hard and Soft Acids and Bases |
QDs | = | Quantum dots |
ODS | = | Oxidative desulfurization |
RP | = | Reduction photocatalyst |
OP | = | Oxidation photocatalyst |
SBU | = | Secondary building unit |
EDTA | = | Ethylenediaminetetraacetic acid |
SHE | = | Standard hydrogen electrode |
CLEF | = | concentrated local electromagnetic field |
Acknowledgments
This paper was supported by the Ferdowsi University of Mashhad Research Council and the RUDN University Strategic Academic Leadership Program.
Disclosure statement
No potential conflict of interest was reported by the author(s).