Cu,Ce-containing phosphotungstates as laccase-like nanozyme for colorimetric detection of Cr(VI) and Fe(Ⅲ)

Herein, a nanocomposite of Cu,Ce-containing phosphotungstates (Cu,Ce-PTs) with outstanding laccase-like activity was fabricated via a one-pot microwave-assisted hydrothermal method. Notably, it was discovered that both Fe³⁺ and Cr⁶⁺ could significantly enhance the electron transfer rates of Ce³⁺ and Ce⁴⁺, along with generous Cu²⁺ with high catalytic activity, thereby promoting the laccase-like activity of Cu,Ce-PTs. The proposed system can be used for the detection of Fe³⁺ and Cr⁶⁺ in a range of 0.667-333.33 μg/mL and 0.033-33.33 μg/mL with a low detection limit of 0.135 μg/mL and 0.0288 μg/mL, respectively. The proposed assay exhibits excellent reusability and selectivity and can be used in traditional Chinese medicine samples analysis.