Supported Crystal/Amorphous Hybrid-Constructed Sensing Array: Exploiting Switchable Enzyme Activity for High Selectivity and Long-Term Cycling Detection of Dihydroxybenzene Isomers

Nanozymes show great potential in environmental monitoring, yet their catalytic performance and recyclability remain challenging. This study developed a supported nanozyme system by pyrolyzing precursors to synthesize ultrafine CuO nanoclusters anchored on hollow sea-urchin-shaped SiO₂ (CuO@SiO₂). The material exhibits switchable peroxidase- and laccase-like activities, strong substrate affinity, and excellent recyclability, attributable to its unique crystal/amorphous hybrid structure. Leveraging this dual-enzyme activity, we constructed a dual-channel sensor array based on the "turn-on" laccase-like and "turn-off" peroxidase-like responses, enabling highly selective discrimination among dihydroxybenzene isomers at concentrations as low as 5 μM. The array successfully identified single isomers, mixed samples, and nine unknown analytes with 100% accuracy. This work provides new insights into supported nanozyme design and demonstrates a multidimensional signal extraction strategy to advance nanozyme sensing technology.