A Stable Polyoxometalate-Based Metal–Organic Framework with Active CoMoO₄ Layers for Electroreduction and Visible-Light-Driven Water Oxidation

Abstract

Polyoxometalate-based MOFs afford a great opportunity in terms of water oxidation. Herein, a new PMOF (SYNU-1) has been constructed with active CoMoO4 layers and TPPE ligands. In SYNU-1, each TPPE ligand bridges eight Co­(II) and Mo­(VI) cations to give a 3D (3,4,5)-connected (62·83·10)­(63)­(65·85) framework. SYNU-1 CPE exhibits electroreduction toward nitrite and bromate. Furthermore, SYNU-1 catalyst demonstrates electrocatalytic OER activity with a low overpotential of 364 mV. Strikingly, the heterogeneous catalyst SYNU-1 shows a high O2 yield (79.05%) for visible light water oxidation with good stability and reusability.

An Anionic Indium–Organic Framework with Spirobifluorene-Based Ligand for Selective Adsorption of Organic Dyes

“…The UV–vis absorption spectrum of solid-state JUC-210 was measured, showing an absorption peak at 399 nm (Figure S6). According to the Tauc plot method, the optical energy gap E g was estimated to be 2.09 eV by extrapolation of the linear part of the absorption edges which demonstrates the semiconductor nature of JUC-210 …”

“…According to the Tauc plot method, the optical energy gap E g was estimated to be 2.09 eV by extrapolation of the linear part of the absorption edges which demonstrates the semiconductor nature of JUC-210. 42 To study the influence of the charges of organic dyes on their adsorption behaviors on a MOF, the dye adsorption onto JUC-210 in DMF, involving MLB, NR, SD I, Orange II, and MO with different charges and similar sizes, was analyzed. Only MLB with a positive charge could be adsorbed by JUC-210.…”

5f Covalency Synergistically Boosting Oxygen Evolution of UCoO4 Catalyst

“… When the applied potential was removed, the energy position of the Co-K edge remained unchanged, retaining that under the OER conditions, which is consistent with the CV results (Figure S12). This is a nice case known for Li 2 Co 2 O 4 because the same information about the electronic structure under the OER can be obtained after the OER by using ex situ surface-sensitive soft XAS (SXAS) spectra in the TEY mode at the Co-L 2,3 and O-K edges (2–4 nm exploring depth), which can provide detailed information about the valence states, , spin states, , local environments of the Co ions, and the unoccupied O 2p states …”

“…The overpotential and Tafel slope of UCoO 4 represent one of the best levels achieved for unitary Co-based OER electrocatalysts in alkaline solutions (Figure e and Table S4). − Furthermore, stability is one of the most important parameters of electrocatalysts. The chronoamperometry curve showed almost no change during the 48 h electrocatalytic process at 10 mA cm –2 .…”

N-Donor flexible ligands for constructing polyoxometalate-based metal–organic frameworks as multifunctional electrocatalysts

“…15,16 Polyoxometalates (POMs) are clusters of inorganic metal oxides, mainly consisting of W, Mo, V, Nb, Ta, and other elements, which are widely applied in catalysis, electrochemistry and other fields due to their diversity in composition, size and structures. [17][18][19][20][21][22] Among them, the most classic Keggin type, such as PW 12 , has become a research hot spot. 23 POMs have unique redox properties that allow them to participate in reversible multi-electron transfer reactions without varying their structure.…”