Catalyzing Generation and Stabilization of Oxygen Vacancies on CeO2-x Nanorods by Pt Nanoclusters as Nanozymes for Catalytic Therapy

Although CeO2 nanomaterials have been widely explored as nanozymes for catalytic therapy, they still suffer from relatively low activities. Herein, the catalyzing generation and stabilization of oxygen vacancies on CeO2 nanorods by Pt nanoclusters via H-2 gas reduction under mild temperature (350 degrees C) to obtain Pt/CeO2-x, which can serve as a highly efficient nanozyme for catalytic cancer therapy, is reported. The deposited Pt on CeO2 by the atomic layer deposition technique not only can serve as the catalyst to generate oxygen vacancies under mild temperature reduction through the hydrogen spillover effect, but also can stabilize the generated oxygen vacancies. Meanwhile, the oxygen vacancies also provide anchoring sites for Pt forming strong metal-support interactions and thus preventing their agglomerations. Importantly, the Pt/CeO2-x reduced at 350 degrees C (Pt/CeO2-x-350R) exhibits excellent enzyme-mimicking catalytic activity for generation of reactive oxygen species (e.g., .OH) as compared to other control samples, including CeO2, Pt/CeO2, and Pt/CeO2-x reduced at other temperatures, thus achieving excellent performance for tumor-specific catalytic therapy to efficiently eliminate cancer cells in vitro and ablate tumors in vivo. The excellent enzyme-mimicking catalytic activity of Pt/CeO2-x-350R originates from the good catalytic activities of oxygen vacancy-rich CeO2-x and Pt nanoclusters.

Automated summary

This study reports the generation and stabilization of oxygen vacancies on CeO2 nanorods by Pt nanoclusters at mild temperature, resulting in a highly efficient nanozyme (Pt/CeO2-x) for catalytic cancer therapy. The Pt deposited on CeO2 serves as a catalyst to generate and stabilize oxygen vacancies, and forms strong metal-support interactions with CeO2. The Pt/CeO2-x-350R exhibits excellent enzyme-mimicking catalytic activity, effectively eliminating cancer cells and ablating tumors in vitro.