Construction of Water-Stable Rare-Earth Organic Frameworks with Ambient High Proton Conductivity Based on Zirconium Sandwiched Heteropolytungstate

Unraveling the enhanced oxidative desulfurization activity: Synergistically boosting the formation of reactive oxygen species and active centers

Hydrogen peroxide (H2O2) activation is a pivotal factor influencing the oxidative desulfurization efficiency. Carbon quantum dots (C-dots) material can be facilely functionalized through chemical modifications, thus effectively activating H2O2 for oxidative reactions. Herein, a kind of hybrid materials C-dots-modified polyoxometalate poly(ionic liquid) supported on silica dioxide (C-PIL-POM-SiO2) were successfully synthesized via a facile self-assembly method. The experimental results demonstrated that the doped C-dots facilitated electron transfer during the reaction, thereby accelerating the conversion of H2O2 into superoxide (·O2-) and hydroxyl radicals (·OH). The incorporation of SiO2 significantly enhanced the specific surface area of the catalysts C-PIL-POM-SiO2, leading to abundant exposed active sites to boost the mass transfer during the reaction. The synergistic effects could achieve an optimal desulfurization efficiency of 99.9 % within 40 min.

Innovative bipyridine-bridged metal porphyrin polymer for Robust and superior electrocatalytic hydrogen evolution

Herein, three bipyridine-bridged metallated porphyrin COPs were synthesized. Bpy-CoTNPP achieves a low HER overpotential of 130 mV at 10 mA cm-2 in alkaline media, surpassing most counterparts. This performance stems from synergistic effects: hierarchical porosity enables rapid mass transport, atomic-level Co-N sites enhance proton adsorption, and bipyridine bridges facilitate electron transfer. The work reveals a cooperative mechanism for optimizing HER catalysis.

Polyoxometalate-based reticular materials for proton conduction: from rigid frameworks to flexible networks

Proton conductors play a crucial role in energy and electronic technologies, thus attracting extensive research interest. Recently, reticular chemistry has propelled the development of reticular materials with framework or network structures, which can offer tunable proton transport pathways to achieve optimal conducting performance. Polyoxometalates (POMs), as a class of highly proton-conducting units, have been integrated into these reticular materials using various linkers. This leads to the creation of hybrid proton conductors with structures varying from rigid crystalline frameworks to flexible networks, showing adjustable proton transport behaviors and mechanical properties. This Frontier article highlights the advancements in POM-based reticular materials for proton conduction and provides insights for designing advanced proton conductors for practical applications.

Aerobic Oxidative Desulfurization by Supported Polyoxometalate Ionic Liquid Hybrid Materials via Facile Ball Milling

With the increasingly strict limitations on emission standards of vehicles, deep desulfurization in fuel is indispensable for social development worldwide. In this study, a series of hybrid materials based on SiO2-supported polyoxometalate ionic liquid were successfully prepared via a facile ball milling method and employed as catalysts in the aerobic oxidative desulfurization process. The composition and structure of prepared samples were studied by various techniques, including FT-IR, UV-vis DRS, wide-angle XRD, BET, XPS, and SEM images. The experimental results indicated that the synthesized polyoxometalate ionic liquids were successfully loaded on SiO2 with a highly uniform dispersion. The prepared catalyst (C16PMoV/10SiO2) exhibited good desulfurization activity on different sulfur compounds. Moreover, the oxidation product and active species in the ODS process were respectively investigated via GC-MS and ESR analysis, indicating that the catalyst can activate oxygen to superoxide radicals during the reaction to convert DBT to its corresponding sulfone in the fuel.

Acenaphthenediimine complex-bridged porphyrin porous organic polymer with enriched active sites as a robust water splitting electrocatalyst

To realize efficient water splitting, a highly promising hydrogen evolution reaction (HER) electrocatalyst is needed for the generation of hydrogen. Herein, we demonstrate a novel acenaphthenediimine complex-bridged porphyrin porous organic polymer (NiTAPP-NiACQ) with enriched active metal sites and hierarchical pores. The as-prepared NiTAPP-NiACQ exhibits good long-term durability and remarkable HER performance in 1.0 M KOH with a low overpotential of 117 mV at 10 mA cm-2, which is comparable to many previously reported electrocatalytic HER systems. Furthermore, a simple water-alkali electrolyzer using NiTAPP-NiACQ as the cathode requires a small cell voltage of 1.59 V to deliver a current density of 10 mA cm-2 at room temperature, along with outstanding durability. NiTAPP-NiACQ features not only a metal ion as the catalytic active center in the porphyrin core but also metal ion coordination on the anthraquinone component to promote HER performance, enabling multiple metal ions as the electrocatalytic active sites for the HER reaction. The excellent HER activity of NiTAPP-NiACQ is ascribed to a combination of mechanisms. These findings highlight the viability of porphyrin-derived porous organic polymers in energy conversion processes.

Boosted hydrogen evolution reaction for a nitrogen-rich azo-bridged metallated porphyrin network

The potential of porous organic polymers (POPs) toward electrocatalytic water splitting have attracted considerable scientific attention, due to their high specific surface areas, superlative porosity and diverse electronic structures; yet it remains challenging. Herein, we report a facile synthesized novel nitrogen-rich azo-bridged metallated porphyrin POP (CoTAPP-CoTNPP) for improving the hydrogen evolution reaction (HER) activity. The incorporation of the cobalt porphyrins and the azo groups endows CoTAPP-CoTNPP with effective charge transfer efficiency and large π-conjugated porous frameworks, thus enhancing the HER performance. Origins of the excellent HER performance of the material are evaluated using a series of structural and electrochemical measurements. Remarkably, CoTAPP-CoTNPP exhibits low overpotentials of 103 and 170 mV to reach 10 mA cm-2 in acidic and alkaline media, respectively, outperforming many previously reported HER electrocatalysts. These results demonstrate the enormous potential of the as-prepared azo-linked porphyrin POP for electrocatalytic water splitting.

Electronic and energy level structural engineering of graphitic carbon nitride nanotubes with B and S co-doping for photocatalytic hydrogen evolution

The ideal photocatalyst used for photocatalytic water splitting requires strong light absorption, fast charge separation/transfer ability and abundant active sites. Heteroatom doping offers a promising and rational approach to optimize the photocatalytic activity. However, achieving high photocatalytic performance remains challenging if just relying on single-element doping. Herein, Boron (B) and sulfur (S) dopants are simultaneously introduced into graphitic carbon nitride (g-C₃N₄) nanotubes by supramolecular self-assembly strategy. The developed B and S co-doped g-C₃N₄ nanotubes (B,S-TCN) exhibited an outstanding photocatalytic performance in the conversion of H₂O into H₂ (9.321 mmol g^-1h^-1), and the corresponding external quantum efficiency (EQE) reached 5.3% under the irradiation of λ = 420 nm. It is well evidenced by the closely combined experimental and (density functional theory) DFT calculations: (1) the introduction of B dopants can facilitate H₂O adsorption and drive interatomic electron transfer, leading to efficient water splitting reaction. (2) S dopants can stretch the VB position to promote the oxidation ability of g-C₃N₄, which can accelerate the consumption of holes and thus inhibit the recombination with electrons. (3) the simultaneous introduction of B and S can engineer the electronic and energy level structural of g-C₃N₄ for optimizing interior charge transfer. Finally, the purpose of maximizing photocatalytic performance is achieved.