Copper based macromolecular catalysts for the hydroxylation of phenols

Dual-function advanced magnetic bacterial cellulose materials: From enhanced adsorption phenomena to an unprecedented circular green catalytic strategy

With the growing emphasis on circular catalysis principles and green chemistry, addressing the dual challenge of wastewater treatment and sustainable catalysis has become increasingly critical. Although the adsorption of copper ions using magnetic biomaterials has been widely investigated, its full potential is still not fully understood. In particular, the reutilization of Cu(II)-loaded magnetic bacterial cellulose in circular green catalytic reactions remains underexplored. This study presents a novel magnetic bacterial cellulose-based material, designated as (BC-BPEM)@Fe3O4NPs, engineered through advanced chemical modifications to address these challenges. The adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the predominant mechanism. A key challenge addressed in this study was the efficient reuse of Cu(II)-loaded magnetic bacterial cellulose-based material. The recovered material was successfully employed as a catalyst in the synthesis of novel 1,4-disubstituted bis-1,2,3-triazoles under green conditions. Notably, the reaction achieved an impressive rate of 0.219 ± 0.006 mmol.gcat-1.min-1 and a 99 % yield within 15 min, using green deep eutectic solvents (ChCl/Gly) and glutathione as a reducing agent. Remarkably, the catalyst retained its high catalytic performance over 20 cycles, maintaining yields consistently between 99 % and 97 %. This study not only emphasizes the seamless integration of adsorption and catalytic recycling but also highlights the sustainability of the approach. Environmental metrics revealed an E-factor of 0.442 kg waste/kg product, a PMI of 1.442 kg materials/kg product, and an RME of 99.83 %, reinforcing the potential of catalyst in both sustainable catalysis and environmental remediation.

Efficient solar-driven: Photothermal catalytic reduction of atmospheric CO2 at the gas-solid interface by CuTCPP/MXene/TiO2

Directly capturing atmospheric CO2 and converting it into valuable fuel through photothermal synergy is an effective way to mitigate the greenhouse effect. This study developed a gas-solid interface photothermal catalytic system for atmospheric CO2 reduction, utilizing the innovative photothermal catalyst (Cu porphyrin) CuTCPP/MXene/TiO2. The catalyst demonstrated a photothermal catalytic performance of 124 μmol·g-1·h-1 for CO and 106 μmol·g-1·h-1 for CH4, significantly outperforming individual components. Density functional theory (DFT) results indicate that the enhanced catalytic performance is attributed to the internal electric field between the components, which significantly enhances carrier utilization. The introduction of CuTCPP reduces free energy of the photothermal catalytic reaction. Additionally, the local surface plasmon resonance (LSPR) effect and high-speed electron transfer properties of MXene further boost the catalytic reaction rate. This well-designed catalyst and catalytic system offer a simple method for capturing atmospheric CO2 and converting it in-situ through photothermal catalysis.

S-scheme heterojunction Cu-porphyrin/TiO2 nanosheets with highly efficient photocatalytic reduction of CO2 in ambient air

Directly capturing CO2 in ambient air and converting it into value-added fuels using photocatalysis is a potentially valuable technology. In this study, Cu-porphyrin (tetrakis-carboxyphenyl porphyrin copper, CuTCPP) was innovatively anchored on the surface of TiO2 (titanium dioxide) nanosheets to form an S-scheme heterojunction. Based on this, a photocatalytic reaction system for stably converting CO2 in ambient air into value-added fuels at the gas-solid interface was constructed without addition of sacrificial agents and alkaline liquids. Under the illumination of visible light and sunlight, the evolution rate of CO is 56 μmol·g-1·h-1 and 73 μmol·g-1·h-1, respectively, with a potential CO2 conversion rate of 35.8 % and 50.4 %. The enhanced of photocatalytic performance is attributed to the introduction of CuTCPP, which provides additional active sites, significantly improves capture capacity of CO2 and the utilization of electrons. Additionally, the formation of S-scheme heterojunction expands the redox range and improves the separation efficiency of photo-generated charges.

Cu ions anchored in the porphyrin center act as transient metal centers of 2D-MOFs to enhance photocatalytic hydrogen production

To improve charge transfer efficiency, non-noble metal Cu anchored in the porphyrin center can realize a new ligand-to-linker metal charge-transfer (LLMCT) process in 2D Ti-based porphyrin MOFs.

Zero-valent iron supported on expanded graphite from spent lithium-ion battery anodes and ferric chloride for the degradation of 4-chlorophenol in water

Zero-valent iron supported with expanded graphite (ZVI/EG) were successfully prepared from ferric chloride and the graphite of spent lithium-ion battery (LIB) using carbothermic reduction as a new approach for recycling spent LIB. ZVI/EG composites synthesized with different ZVI mass ratios were used as catalysts for the 4-chlorophenol (4-CP) removal from water by heterogeneous Fenton reactions. ZVI/EG composites showed a BET specific surface area of 11.295 m² g^-1. ZVI/EG synthesized from expandable graphite and ferric chloride with mass ratio of 2:1 (ZVI/EG-2) showed the highest removal percentage of 4-CP, being 97% in 1 h. The degradation rate fitted to a pseudo first-order model better, and reached 0.0527 min^-1 for ZVI/EG-2. Moreover, ZVI/EG-2 showed high reactivity for 4-CP removal even in the sixth reuse cycle, being 82%. Hydroquinone and 4-chlorocatechol were identified as the intermediate products of 4-CP degradation. Increasing the ZVI/EG-2 dosage can enhance the 4-CP removal percentage through offering more reactive sites and Fe²⁺ ions. Acidic pH values favorited the 4-CP removal due to the high H⁺ concentrations, while Alkaline pH value inhabited the 4-CP removal. A higher temperature increased the rate of •OH formation and enhanced the 4-CP removal percentage. At a fixed dosage of the ZVI/EG-2, the ratio of available reactive sites was less at higher initial concentrations. These results prove the possibility of synthesizing high active and stable ZVI/EG catalysts using graphite from spent LIB and ferric chloride. These catalysts show promising prospective for the 4-CP removal in water, with comparable activities to others previously reported.

2D hydrogen-bonded organic frameworks: in-site generation and subsequent exfoliation

By using in-site generated formate, 2D HOFs of TCPP, with excellent stability and permanent porosity (BET surface area larger than 560 m2 g-1), have been obtained. The constructed 2D square-like TCPP-HCO2 grid sheets have shown considerable in-plane stability that comparable to the TCPP-based 2D MOFs, that can be exfoliated into atomically thin 2D nanosheets with efficient photocatalytic activity in aqueous system. These results are expected to shed light on the application-orientated one-pot synthesis for new kinds of multi-dimensional HOFs.