Brønsted Acid-Functionalized Ionic Co(II) Framework: A Tailored Vessel for Electrocatalytic Oxygen Evolution and Size-Exclusive Optical Speciation of Biothiols

Abstract

Metal−organic frameworks (MOFs) not only combine globally demanded renewable energy generation and environmental remediation onto a single platform but also rationalize structure−performance synergies to devise smarter materials with remarkable performance. The robust and non-interpenetrated cationic MOF exemplifies a unique bifunctional scaffold for the efficient electrochemical oxygen evolution reaction (OER) and ultrasensitive monitoring of biohazards. The microporous framework containing Brønsted acidfunctionalized [Co 2 (μ 2 -OH)(CO 2 ) 2 ] secondary building units (SBUs) exhibits remarkable OER performance in 1 M KOH, requiring 410 mV overpotential to obtain 10 mA cm −2 anodic current density, and a low Tafel slope of 55 mV/dec with 93.1% Faradaic efficiency. Apart from the high turnover frequency and electrochemically assessable surface area, steady OER performance over 500 cycles under potentiodynamic and potentiostatic conditions result in long-term catalyst durability. The highly emissive attribute from nitrogen-rich fluorescent struts benefits the MOF in recyclable and selective fluoro-detection of three biothiols (L-cysteine, homocysteine, and glutathione) in water with a fast response time. In addition to colorimetric monitoring in the solid and solution phases, control experiments validate size-exclusive biothiol speciation through molecular-dimension-mediated pore diffusion. The role of SBUs in the OER mechanism is detailed from density functional theory-derived free energy analysis, which also validates the importance of accessible N-sites in sensing via portraying framework−analyte supramolecular interactions.

Atmospheric-Water-Induced Reversible Structural Transformation of a Two-Dimensional Ni(II)-Based Ferromagnetic MOF: A Highly Efficient Water Oxidation Electrocatalyst and Colorimetric Water Sensor

“…Physicochemical Stability of MOF1 and MOF2. The physicochemical robustness of MOF1 and MOF2 was investigated by soaking single crystals of MOF1 in media with various pHs (0.01 M HCl, HEPES buffer, 0.01 M KOH), 76 subjecting MOF1 to certain severe conditions. Since MOF1 has an intrinsic tendency to transform to MOF2 with the assistance of water, we obtained MOF2 (blue) in each case.…”

Deciphering the role of functional synergy in a catalytic molecular assembler: a proof of concept for boosted catalysisviaretrosynthetic linker scissoring

“…2(d) shows the high-resolution XPS spectrum of Co( ii ) 2p with distinctive peaks of Co 2p 3/2 and Co 2p 1/2 at binding energies (BEs) 780.66 and 796.45 eV, respectively. 43 Moreover, two different satellite (Fig. 2(d)) peaks for Co 2p 3/2 and Co 2p 1/2 are observed at 784.66 and 801.18 eV, respectively.…”

“…S9, ESI †) showed increased performance with the increase in concentration of KOH solution, and points that O 2 evolution is proportionally boosted as a result of maximising the number of OH À ions to the catalyst surface. 43,51 Moreover, the Nyquist plot apprises a lower charge transfer resistance (R ct ) value (4.44 O) for 20a when compared with RuO 2 (6.03 O) and Co 3 O 4 (7.01 O). This observation implies enhanced feasibility of electron transfer for 20a (Fig.…”

Largely Entangled Diamondoid Framework with High-Density Urea and Divergent Metal Nodes for Selective Scavenging of CO2 and Molecular Dimension-Mediated Size-Exclusive H-Bond Donor Catalysis

“…Considering the aforementioned facts and challenges, coupled with our ongoing efforts to develop pore-functionalized multimodal MOFs for assorted sustainable applications, − we constructed a three-dimensional Zn­(II) framework CSMCRI-17 (CSMCRI = Central Salt and Marine Chemicals Research Institute) with dia topology using a mixed ligand assembly. The MOF reveals a number of fascinating structural attributes like (i) polar azo-functionality in ( E )-4,4′-(diazene-1,2-diyl)­dibenzoic acid ligand (H 2 azdc ) that acts as a guest interaction site, (ii) suitably orientated urea moieties from 1,3-di­(pyridin-4-yl)­urea linker ( L ), decorating the pore wall, and (iii) seven-fold interpenetration-induced creation of optimum-sized porous channels, leading to pore-fitting-mediated size selectivity.…”