How to overcome the intrinsic low activity of most oxidase and peroxidase mimics at neutral pH has been extremely challenging. Herein, we represent a chromium-mediated and ligand-dependent strategy to activate the oxidase-like activity of boron-doped g-C3N4 (B-g-C3N4, denoted as BG), aiming at breaking the pH limitation. Cr (III) can be in situ oxidized to Cr (IV) by generated •O2– upon UV light irradiation, which then works as a catalysis mediator to oxidize TMB under a neutral environment. Excitingly, the TMB oxidation can be rationally modulated by ligands on the BG coordinating with chromium. We verify that the PEI-Cr3+ coordination outperformed Cit-PEI-Cr3+ on the oxidase-like activity through a more accelerated electron transfer, unveiled by the Gauss theoretical calculations. This study highlights a paradigm of tuning the coordination environment on nanozyme surface via the ligand engineering strategy for boosting the oxidase-mimicking activity and breaking the pH limitation. Meanwhile, the catalysis-based colorimetric assay for accurate and selective identification of Cr3+ was achieved.
Xu Lu,Wang Aili,Li Siqiang,Zhang Liya,Pan Ruiyu,Guo Peng,Yi Ming,Liu Jie
Biomass residue cellulose-based poly-(ionic liquid)s (ILs) were in situ synthesized via activators generated by electron transfer for atom transfer radical polymerization in ionic liquid microemulsions. These biomass residues, including apple residue, citrus residue, and ginkgo leaf, were started with pretreatment and modification in ionic liquid microemulsions, and their structure and thermal stability were significantly altered before and after modification as confirmed by scanning electron microscopy and thermogravimetric analysis. Fourier-transform infrared spectroscopy and 31 P nuclear magnetic resonance spectroscopy were used to investigate the molecular structure of the biomass residue cellulose-based poly-ILs. In addition, the adsorption performance of the biomass residue cellulose-based poly-IL adsorbents for heavy metal ions, such as Cd(II), Zn(II), Cr(IV), Cu(II), Mn(II), Ni(II), and Pb(II), in water were investigated. Results show that the prepared adsorbent possesses good thermal stability and certain adsorption capacity for metal ions in water, especially for nickel ions (93.91 mg/g). The prepared adsorbent also exhibits remarkable performance in the field of biomass residue utilization and novel poly-IL adsorbents.
危险品化学品经营许可证（带存储）