Tuning d-Band Center of FeCu Alloy Aerogel Nanozyme Boosting Biosensing and Wound Therapy

Transition metals especially Fe-based catalysts representing an emerging type of enzyme-mimicking materials are of great interest in biosensing and therapy fields. However, the poor affinity toward H2O2 limits their catalytic activity while high-precise and controllable regulation of engineering nanozymes remains a challenge. Herein, a facile approach is presented to fabricate FeCu/hemin aerogel nanozymes with self-supported, hierarchically porous network structures through second metal center and surface ligand engineering, achieving sequential H2O2-affinity amplification. Excitingly, the affinity of FeCu/hemin nanozymes for H2O2 exhibits a 14.03-fold enhancement than that of Fe particle, accompanied with 5.88-fold catalytic efficiency (Kcat/Km) increase than FeCu. Mechanism studies suggest that the metal Cu and hemin modifications upshift the d-band center of Fe from -0.49 to -0.17 eV and promote electron transfer process, thus facilitating the dissociation of H2O2. Importantly, FeCu/hemin nanozymes allow highly sensitive detection of norfloxacin with a low detection limit of 72 nm. Notably, it shows a remarkable inhibition activity on bacterial growth in vitro and in vivo with no apparent side effects. Therefore, this work not only sheds light on the rational design of nanozymes with highly active and stable properties, but also offers new prospects for the d-band center tuning to boost enzyme-mimic activity.