Modulation of High-Spin Co(II) in Li/Co-MOFs as Efficient Fenton-like Catalysts

Abstract

Developing high-performance catalysts toward the Fenton reaction is important for environmental protection and sustainable development, yet it is still challenging. The high-spin states of first-row transition metal atoms with tetrahedral coordination provide a flexible electronic environment to activate the catalyst and elevate its catalytic activity. As a type of material with adjustable structures, metal−organic frameworks (MOFs) are excellent candidate catalysts as they can accurately regulate the coordination configurations of metal ions. In this paper, we investigate and summarize the direct formation of bimetallic carboxylate Li/Co-MOFs with tetrahedral coordination metal centers in a mixed H 2 O/polar organic solvent system. The induction of Li(I) ions is manifested in the generation of hydroxides during the dissociation of the Co(II) solvation structure to trigger the tetrahedral coordination behavior of Co(II). These Li/Co-MOFs containing high-spin Co(II) centers can serve as highly efficient Fenton-like catalysts for organics. This study provides a promising strategy for rational design of MOF-based catalysts with high-spin metal centers for application in environment governance.

Chalcogen Elements in Regulating the Local Electron Density of Cu2X for an Efficient Heterogeneous Fenton-like Process

“…And to this point, efficient heterogeneous Fenton catalysts are required to provide abundant electrons for the H 2 O 2 conversion process. 15,16 Especially, chemical reactions usually occur on the outer shell electrons of center atoms, in which the local electron density has been considered as the core factor determining its reaction characteristics. 17 In transition-metal catalysts with reactive d-band electrons, like Pt, Fe, Cu, and Ni, the catalytic performance intensively depends on the local electron density.…”

“…From the above analysis, the essence of these strategies is to strengthen the above electron transfer processes between center active atoms and H 2 O 2 . And to this point, efficient heterogeneous Fenton catalysts are required to provide abundant electrons for the H 2 O 2 conversion process. , …”

Dual-Ligand Strategy for the Design and Construction of a Cd–Zn Heterometallic Metal–Organic Framework by One-Pot Synthesis as a Heterogeneous Catalyst for the Epoxidation Reaction of Olefins

“…MOFs that include multiple metals in their lattice could be used in heterogeneous catalysis to pursue tandem catalysis or catalyze two independent processes simultaneously. Catalytic activity in heterometal MOFs could be enhanced by the generation of defects and the synergistic effect between the two metals. − Additionally, MOFs are solid catalysts that can contain ligands substituting for active sites that can participate in the catalyst along with metal nodes. Mixed linkers can also be incorporated into the MOF structure, offering a versatile platform for heterogeneous catalysis since they have variable physiochemical properties. − Also, good stability of MOFs, containing mechanical, thermal, and chemical stability, plays a key role during the designing of new MOFs to gain the maximum potentiality of the developed framework …”

Brown TiO2-Based Fe–Ni Thiospinel Binary Nanocomposite as a Sustainable Catalyst with Synergistic Improvement Assisted by H2O2 and Ascorbic Acid for Round-the-Clock Removal of Rhodamine B

“…Advanced oxidation processes (AOPs) are applied technologies used to efficiently treat wastewater by generating reactive oxygen species (ROS) . Depending on the production route of ROS involved in organic pollutants, AOPs are classified into ozonation, photocatalysis, , Fenton/Fenton-like catalysis, − photo-Fenton/photo-Fenton-like, − phyto-Fenton, electrochemical oxidation, sulfate radical-based AOPs, etc. As a promising AOP, the Fenton process describes a simple method for the formation of OH radicals from the decomposition of hydrogen peroxide using iron ions (Fe 2+ /Fe 3+ ) as catalysts in an acidic aqueous solution at room temperature .…”