Recent Advances in Photocatalysis over Metal–Organic Frameworks‐Based Materials

Abstract

To meet the requirements for sustainable development, photocatalytic applications including water splitting, CO2 reduction, pollutant degradation, and organic conversion reactions have become hot topics for research, due to the predictable advantages of energy storage and transportation. Metal–organic frameworks (MOFs) featured with porosity, crystallinity, and tunable constitution offer enormous potential in photocatalytic applications. Herein, a critical overview of MOFs‐based photocatalysts is presented. Following a concise introduction of the structural characteristics of MOFs, the synthesis methods of MOFs‐based photocatalysts are summarized. Moreover, subtle modification strategies for MOFs inspired by the development of other inorganic photocatalysts are also discussed on the basis of the photocatalytic mechanisms of light absorption, electron transfer, and surface catalytic reactions. Furthermore, the applications of certain MOFs‐based photocatalysts are introduced in detail. In addition, other organic frameworks‐based photocatalytic materials, such as covalent organic frameworks and covalent triazine frameworks, are also described to provide a guided insight into the rational design and fabrication of efficient frameworks‐based photocatalysts. Finally, a brief conclusion and perspective on the opportunities and challenges for the future development of MOFs‐based photocatalysts are proposed.

Titanium‐Based MOF Materials: From Crystal Engineering to Photocatalysis

“…Photocatalytic reactions such as H 2 production, CO 2 reduction, H 2 O 2 production, N 2 fixation, waste remediation, photocatalysis of organic reaction, and photocatalytic sensors are conducted to mimic natural photosynthesis involving solar energy. [82][83][84][85] Key processes for photocatalysis include 1) light harvesting; 2) photogenerated electron-hole pairs separation and transportation; 3) reduction reaction with electron or oxidation reaction with hole. [86] Integrating with photosensitizer and catalytic sites in a single crystal, titanium-based MOFs are a kind of promising photocatalysts that possess excellent light-harvesting and catalytic ability.…”

Progress and challenges in photocatalytic ammonia synthesis

“…Photocatalytic reduction of N2 to produce NH3 by utilizing photocatalysts and water, driven by renewable solar energy, has huge perspective, thereby is very significant. [11][12][13][14][15][16][17] Since the seminal work of Schrauzer and Guth, where TiO2 photocatalyst showed the N2 reduction activity with water and N2 in 1977, 17 various semiconductors have been studied for the photocatalytic production of NH3, such as ZnO, Fe2O3, Ga2O3, W18O49, BiOBr, BiOCl, CdS, layered double hydroxides, polymeric carbon nitride and so on. [18][19][20][21][22][23][24][25] The main challenges for the photocatalytic synthesis of NH3 are the chemical adsorption and activation of N2.…”

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

“…MOFs are a class of 3D crystalline micro‐/mesoporous hybrid materials constructed from metal or metal cluster nodes interconnected with multidentate organic linkers, which have already shown a variety of applications. [ 44–52 ] In particular, as structural analogs of zeolites, MOFs exhibit great potential in heterogeneous catalysis, due to the presence of different catalytic active sites and the existence of interconnected, ordered yet tunable pores in their structure, which not only promote mass diffusion and substrate–catalyst interactions in the reactions, but also introduce size/shape selectivity in MOF‐based catalysis. [ 53–61 ] In addition, to be applied in photocatalysis, a unique type of heterogeneous catalysis involving the use of a light source to initiate the reactions, MOFs are also required to make efficient use of solar light.…”

“…[ 66,67 ] With all these advantages, MOFs have been successfully applied in a variety of photocatalytic reactions, including CO 2 reduction, [ 68–71 ] hydrogen evolution, [ 72–76 ] pollutant degradations, [ 77–81 ] as well as organic transformation. [ 36,82–84 ]…”