Bimetallic Pt-Ni_0.5 nanoparticles with enhanced oxidase like activity for Hg²⁺ detection in water

Hg²⁺ has highly sulfur affinity which was harmful to human health. Noble metal nanomaterials with peroxide-like activity have been widely exploited to develop ultra-sensitive Hg²⁺ colorimetric detection methods. Unfortunately, using large quantities of H₂O₂ in these approaches lowered the catalytic activity's high stability, which made the detection signal less reproducible. Thus, it is critical to explore novel oxidases with high catalytic activity to create ultrasensitive, low-cost Hg²⁺ colorimetric detection method.

In this study, bimetallic Pt-Ni_0.5 nanoparticles with oxidase-like activity were synthesized by hydrothermal method, which significantly improved the material's catalytic activity via both geometric and electrical modulation, resulting in sensitive detection of Hg²⁺ in water. For tap water, drinking water and lake water samples, the limits of detection of the colorimetric method were 0.287 nM, 0.287 nM, 0.51 nM, respectively. A parallel analysis in 3 real samples was confirmed by ICP-MS, the results showed good correlations (R² > 0.98), indicating the practical reliability of this method.

The bimetallic Pt-Ni_0.5 nanoparticles with high oxidase-like activity which don't require H₂O₂ during the catalytic detection process, simplifying the determination procedure, yielding a more stable and dependable output signal for detection and lowering the cost of Hg²⁺ detection. The sensitivity of the colorimetric sensor in UV-vis mode was 2.8-30 times higher than that of the similar methods. Thus, the developed Hg²⁺ colorimetric sensor provides stable and economical technical support for ultrasensitive detection of Hg²⁺ in real water samples. This study will greatly promote the application of rapid trace detection of Hg²⁺ in water.