One-step synthesis of an organotin-functionalized polyoxometalate@ZIF-67 composite: an effective non-enzymatic colorimetric acetone sensor†

Abstract

In this work, it was found that organotin-functionalized tungstophosphates PW₉-TM-SnRCOO and P₂W₁₅-TM-SnRCOO (PW₉ = [PW₉O₃₄]⁹⁻; P₂W₁₅ = [P₂W₁₅O₅₆]¹²⁻; TM = Mn, Co, Zn; R = CH₂CH₂) exhibited mimicking horseradish peroxidase (HRP) activity, with the catalytic activity of PW₉-TM-SnRCOO being higher than that of P₂W₁₅-TM-SnRCOO. Among the polyoxometalates (POMs), those containing Zn ions demonstrated the highest catalytic activity. Furthermore, a recyclable POM-based ZIF-nanocomposite, Na₈K₂[Zn₂{Sn(CH₂)₂COO}₂(B-α-PW₉O₃₄)₂]·13H₂O@ZIF-67 (PW₉-Zn-SnRCOO@ZIF-67), was designed and synthesized using a convenient one-step method at room temperature. As a mimic enzyme of HRP for the catalytic oxidation of o-phenylenediamine (OPD), PW₉-Zn-SnRCOO@ZIF-67 exhibited enhanced catalytic activity and anti-interference ability. Moreover, the introduction of the POM-estertin derivative significantly improved the acid resistance of ZIF-67. PW₉-Zn-SnRCOO@ZIF-67 can be further used as a colorimetric sensor material for the detection of acetone with a wide linear range (0.01–4.0 mM), a low detection limit (0.0074 mM), and good reusability. These results demonstrate that organotin-functionalized POMs@ZIFs, as a new class of non-enzymatic sensor materials, have wide application prospects for the detection of acetone in real water samples.