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

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-alpha-PW9O34)2]<middle dot>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.