2D Co3O4 modified by IrO2 nanozyme for convenient detection of aqueous Fe2+ and intercellular H2O2
A portable sensor for visual monitoring of Fe 2+ and H 2 O 2 , two-dimensional Co 3 O 4 modified by nano-IrO 2 (IrO 2 @2D Co 3 O 4 ) was prepared in this work, for the first time, with the help of microwave radiation at 140 °C, which was further stabilized onto common test strips. The present IrO 2 @2D Co 3 O 4 possessed superior dual-function enzyme-like activity with low toxicity and excellent biocompatibility. Especially, trace Fe 2+ and H 2 O 2 could exclusively alter their enzyme-like catalytic activity with discriminating hyperchromic or hypochromic effect, i.e., from blue to colorless or to dark blue for both IrO 2 @2D Co 3 O 4 dispersion and its functionalized test strips. The linear regression equations were A 652 = 0.5940 − 0.00041 c Fe 2+ (10 −8 M, R 2 = 0.9927) for Fe 2+ and ∆A 652 = 0.0023 c H2O2 + 0.00025 (10 −7 M, R 2 = 0.9982) for H 2 O 2 , respectively. When applied to visual monitoring of aqueous Fe 2+ and intercellular H 2 O 2 , the recoveries were 101.2 ~ 102.5% and 95.8 ~ 103.7% with detection limits of 1.25 × 10 −8 mol/L and 1.02 × 10 −7 mol/L, respectively, far below the permitted values in drinking water set by the World Health Organization. The mechanisms for the enhancing enzyme-mimetic activity of IrO 2 @2D Co 3 O 4 and its selective responses to Fe 2+ and H 2 O 2 were investigated in detail. Graphical Abstract
危险品化学品经营许可证（带存储）