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A series of zirconium-based MOFs with acclaimed stability was prepared and their ability to adsorb polyfluorinated pollutants was compared. A novel fluorinated UiO-67 analogue, UiO-67-F2, was synthesised alongside three previously reported materials: UiO-67-NH2, UiO-68-(CF3)2 and UiO-67. The structures were established and confirmed by powder X-Ray diffraction. UiO-67-NH2, UiO-68(CF3)2 and UiO-67-F2 were examined as sorbents for the perfluorinated gas, sulphur hexafluoride (SF₆) from the gaseous phase. The SF₆ uptake of UiO-67-NH2 and UiO-67-F2 at 100 kPa, 293 K, was high (5.54 and 5.24 mmol g ^-1 respectively). UiO-67-F2 exhibited a remarkable perfluorinated octanoic acid (PFOA) uptake of 928 mg_PFOA g ^-1_MOF in an aqueous solution, which far exceeded that of unmodified UiO-67 (872 mg_PFOA g ^-1_MOF at 1 000 mg_PFOA L ^-1_Water PFOA). This study has identified strengths and potential applications of the novel UiO-67-F2 and the impact of fluorine functionalization. The study also offers insight into the structure-property relations of UiO-based MOFs for their use as low-pressure SF6 storage materials and PFAS sorbents intended for water purification under ambient conditions.

Molecular catalysts for water oxidation and other electrochemical transformations have been a focus of significant research over recent decades. Among these, α-[Fe(mcp)L2] complexes stand out as one of the most active non-heme iron-based molecular catalyst for water oxidation. This study investigates how the Fe(II)/Fe(III) redox potential of these catalysts varies with the identity of their labile ligands (L). Using cyclic voltammetry and complementary spectroscopic techniques (UV/Vis, 1H-NMR), we examined how ligands bind to the metal centre. Systematic variation of the labile ligand (L) demonstrated that the catalyst's redox potential in acetonitrile solution strongly depends on ligand identity. By introducing stoichiometric amounts of different anions to the electrolyte, the redox potential was tuned across a 1.5 V potential window.In aqueous solutions, the redox potential depended on both pH and electrolyte anion identity. These dependencies were successfully fitted to a thermodynamic model that was obtained by extending the typical proton-coupled electron transfer square scheme into a cube scheme that incorporates anion binding. The equation derived from this model provides valuable insights into the ligand-binding dynamics at the iron centre under diverse conditions.

Organic redox-active quinones are promising candidates for future energy storage. While aqueous electrolytes offer advantages such as safety, sustainability, and low cost compared to organic electrolytes, the oxidized states of quinones are typically electron-deficient and prone to nucleophilic attack by water, hindering the development of high-potential quinone-based cathodes. Acidic electrolytes can shift the formal potential of quinones to higher values, but they introduce challenges such as corrosion of battery components (e.g., current collector, anode, separator) and increased risk for end-users. These issues highlight the need for high-potential quinone cathodes in neutral aqueous electrolytes. In this study, we employed proton-trap technology to increase the formal potential of 1,4-benzoquinone (Q) by 0.21 V in a neutral aqueous medium. The proton-trap mechanism involves integrating pyridine/pyridinium into the cathode as a proton acceptor/donor for H2Q/Q redox transfer, enabling internal proton transfer. This effectively decouples the Q redox chemistry from the electrolyte pH. Using proton-trap technology, the H2Q/Q redox couple maintained a constant formal potential of 0.42 V (vs. SHE) in aqueous electrolytes across a pH range of 3-9. The proton-trap poly(1Q-2pyridine-EDOT) copolymer exhibited an initial capacity of 65.5 mAh/g at 10 C, with 83 % capacity retention after 100 cycles. When paired with an anthraquinone (AQ) anode, the all-quinone organic battery delivered a voltage output of 0.9 V in a 17 M NaClO4 pH-neutral aqueous electrolyte. This approach offers a promising pathway for stable, high-potential quinonebased energy storage in safe and sustainable aqueous systems

In bioelectronics, the preservation of host homeostasis upon alteration of the electrical charge caused by an implantable electrode has not yet been addressed properly. Here, we propose an in vitro strategy to evaluate the appearance of acidic regions in conducting polymer film electrodes due to the hosting of proton-coupled electron transfer (PCET) of bioinspired redox quinone molecules. The effects of electrode-inherent ion transport selectivity as well as the media-inherent buffer capacity on the response of a molecular pH probe, being the quinone redox process, were evaluated using the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). The hosting of the PCET, within the phase of the mixed ion-electron conductor, affects both the surrounding characteristics and the diffusion of the redox molecules. The involvement of di-anion quinone in the primary doping of the conducting polymer results in slowing down its diffusion within the bulk of the porous electrode. The redox process, imposed on the porous electrode in the weakly buffered media, controls the electrode operation in vivo. This leads to the appearance of two acidic regions located at the electrode bulk and at the interface between the electrode and the hosting electrolyte, respectively. The proposed methodology is highly relevant for the pre-evaluation of porous electrodes for various (bio-)technological applications.

Quinones exhibit considerable promise as active components in energy storage applications, owing to their high theoretical storage capacity, well-defined redox potentials, rapid reaction kinetics, structural diversity, and proficiency in cycling both protons and metal ions. In this study, six quinone derivatives underwent comprehensive electrochemical and computational analyses using TBA+, H+, Li+, K+, Na+, Ca2+, and Mg2+-based electrolytes, aiming to uncover novel cycling chemistries with organic materials. Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) elucidated the widely recognized 2H+/2e- redox process during proton cycling, as well as the two-step 1e- redox process in the presence of other cycling ions. Additionally, it was established that the quinone formal redox potential for different cycling chemistries followed the sequence TBA+ < K+ < Na+ < Li+ < H+, and cycling of the divalent cations resulted in potentials within the same range as those observed for proton cycling. DFT calculations provided insights into how cycling ions influenced the quinone formal redox potential, attributing it to the cation’s ability to accommodate a portion of the bisolate anion charge upon reduction. Cations inducing a higher quinone formal redox potential and accommodating a larger fraction of the negative charge demonstrated a greater stabilizing effect on the reduced state. This stabilizing effect exhibited a strong correlation with the ionization energies of the respective cations.

Anthropogenic greenhouse gas emissions pose a serious threat to our environment. Therefore, the development of efficient systems to mitigate these issues is of utmost importance. In recent years, Sulphur hexafluoride (SF ) has garnered increasing attention due to its global warming potential, which greatly exceeds that of CO2 on a 100-year scale.

These studies were undertaken to investigate SF6 sorption in novel metal-organic framework materials (MOFs)and how their components affect their function. First, the influence of secondary building units on coordination and sorption properties (SBUs) of SF6 on Ytterbium, Thulium, Cerium and Hafnium 1,3,6,8-tetrakis(4-carboxyphenyl) pyrene-based (TBAPy4−) MOFs was investigated. Secondly, the possibility of altering surface-chemical properties by pre-synthesis fluorination/amination of UIO-67/68 isostructures was studied.

In the first case, the SF6 sorption properties of four novel, highly porous 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene-based (TBAPy4−) MOFs containing either Ytterbium, Thulium or Cerium all in the +3-oxidation state, orHafnium (+4) was studied. Pore size effects, coordination-effects on structure, and gas sportive propertieswere investigated and found to change and in some cases improve in the case of SF6 adsorbate.

In the second case, the structures remain the same throughout these different changes, maintaining the Fmmcrystallographic space group characteristic for UIO-MOFs, enabling investigation of the effect of fluorination in isolation from other possible changes. While adding one more novel material. These changes in turn cause changes in SF6 working capacity, uptake, selectivity in simulated binary mixtures and isothermal enthalpy of adsorption. The influence of specific surface area on the isosteric enthalpy of adsorption revealed differences between functionalities.

There is a multi-faceted purpose in these studies. The creation of novel structures contributes to the basic science and understanding of MOFs in general. There is the proposed use of MOFs as swing adsorption adsorbents and in CCUS or more specifically, SF6 sorption. In addition to these purposes, the insight into these material properties can pave the road to more advanced interactions downstream, such as direct air capture of water, in-site catalysis or similar applications. These diverse applications each have intricacies that can be addressed within MOFs and the scientific groundwork surrounding them.

Molecular catalysts are attracting interest as drivers of redox reactions for sustainable applications. Through systematic molecular design, they could be engineered to have high selectivity and activity towards a multitude of catalytic reactions. However, as long as they are used in homogeneous setups, they will suffer from inconvenient energy supply, inefficient charge transport and difficulty in separation from reaction products. To be relevant for industrial applications, molecular catalysts must be bound to solid materials in direct contact with the energy source. In this regard, conducting polymers are particularly interesting, as they provide a straightforward means of both surface immobilization and charge transport. In this work, we synthesize and characterize three different metalloporphyrin-functionalized conducting polymers and apply them to catalysis of the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR). We show that incorporation of porphyrins into conducting polymers is a reliable immobilization method, that the properties of both the porphyrin units and the polymer backbone are preserved in all systems, and that the polymers provide efficient charge transport to and from the catalytic centers. Nevertheless, we also find that the polymers are negatively affected by intermediates formed during the HER and the ORR. We conclude that the choice of immobilization method has a large impact on the quality of the molecular catalyst, and that the effect of the catalytic cycle on the immobilization matrix must be considered in the molecular design process.