Enhanced Visible-Light-Driven Hydrogen Production through MOF/MOF Heterojunctions

Abstract

A strategy for enhancing the photocatalytic performance of MOF-based systems (MOF: metal−organic framework) is developed through the construction of MOF/ MOF heterojunctions. The combination of MIL-167 with MIL-125-NH 2 leads to the formation of MIL-167/MIL-125-NH 2 heterojunctions with improved optoelectronic properties and efficient charge separation. MIL-167/MIL-125-NH 2 outperforms its single components MIL-167 and MIL-125-NH 2 , in terms of photocatalytic H 2 production (455 versus 0.8 and 51.2 μmol h −1 g −1 , respectively), under visible-light irradiation, without the use of any cocatalysts. This is attributed to the appropriate band alignment of these MOFs, the enhanced visible-light absorption, and long charge separation within MIL-167/MIL-125-NH 2 . Our findings contribute to the discovery of novel MOF-based photocatalytic systems that can harvest solar energy and exhibit high catalytic activities in the absence of cocatalysts.

Self-Assembly of a 3D Hollow BiOBr@Bi-MOF Heterostructure with Enhanced Photocatalytic Degradation of Dyes

“…Photocatalytic degradation has been considered to be an effective and promising method for removing organic dyes from industrial wastewater, − where the separation of photogenerated charge carriers and the effective absorption of dye molecules are crucial in the degradation processes . Thanks to their strong ability to capture dye molecules, high surface area, flexible skeleton structure, diversified functions, and intriguing tailorable features, metal–organic frameworks (MOFs) seem to be a promising porous photocatalyst in realizing the efficient degradation of dyes, − while MOFs themselves exhibit very poor transmission/separation efficiency of photogenerated charge carriers and limited visible light adsorption ability. − Consequently, several efficient inorganic semiconductor/MOF-based heterojunctions, such as TiO 2 @MOF, CdS–NRs/MOF, g-C 3 N 4 /MOF, and BiOBr/MIL-53­(Fe), − were developed to significantly improve their photocatalytic performance. Normally, the MOF-based heterostructure was fabricated by the postsynthesis method, where the semiconductors (TiO 2 , CdS, g-C 3 N 4 ) were directly introduced into the metal ions and ligand solution. − The problem was that the interface between inorganic semiconductors and MOFs lacked an effective combination.…”

MOFs-Derived Zn-Based Catalysts in Acetylene Acetoxylation

“…MOFs are crystalline nanoporous materials with a framework structure composed of transition metal ions and organic ligands [ 18 ], with the metal components dispersed one by one through organic ligands. On account of the large specific surface area, abundant pore structure, and surface defects of MOFs, MOFs have become a research hotspot in the fields of gas storage, gas adsorption, separation, sensors, drug controllable release, and catalytic reactions [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Because of their excellent chemical and thermal stability, MOFs are also used as a template or precursor for the preparation of porous carbon materials or metal composite materials [ 26 ].…”

Progress in Hybridization of Covalent Organic Frameworks and Metal–Organic Frameworks

“…Due to their structural diversity and adjustability, both MOFs and COFs are ideal host molecular platforms for integrating various guests including polymers, metal-and semiconductor oxide nanoparticles (NPs) into periodically ordered organic structures to create MOF or COF-based hybrid materials. [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] For example, the frameworks of MOFs and COFs can be designed and finely tuned using different metal nodes/organic ligands in either framework via surface-modified encapsulation or in situ generation in cavities to immobilize or encapsulate other functional materials, such as polymers, quantum dots, NPs, and enzymes. [69,[84][85][86][87][88][89][90][91][92][93] Interestingly, when compared to single-component materials, MOF or COF-based hybrid materials always exhibit dramatically enhanced or even novel properties derived from the synergistic effects of different modules.…”