Hot Carriers and Photothermal Effects of Monolayer MoO_x for Promoting Sulfite Oxidase Mimetic Activity

Local surface plasmon resonance (LSPR)-enhanced catalysis has brought a substantial amount of opportunities across various disciplines such as photocatalysis, photodetection, and photothermal therapeutics. Plasmon-induced photothermal and hot carriers effects have also been utilized to activate the enzyme-like reactions. Compared with natural enzymes, the relatively low catalytic performance of nanozymes severely hampered the potential applications in the field of biomedicine. For these issues mentioned above, herein, we demonstrate a highly efficient sulfite oxidase (SuOx) mimetic performance of plasmonic monolayer MoOx (ML-MoOx) upon LSPR excitation. We also established that the considerable photothermal effect and the injection of hot carriers induced by LSPR are responsible for promoting the SuOx activity of ML-MoOx. The high transient local temperature on the surface of ML-MoOx generated by the photothermal effect facilitates to impact the reaction velocity and feed the SuOx-like activity, while the generation of hot carriers which are suggested as predominant effects catalyzes the oxidation of sulfite to sulfate through significantly decreasing the activation energy for the SuOx-like reaction. These investigations present a contribution to the basic understanding of plasmon-enhanced enzyme-like reaction and provided an insight into the optimization of the SuOx mimetic performance of nanomaterials.