Tuning Catalytic Activity and Selectivity in Photocatalysis on Mie-Resonant Cuprous Oxide Particles: Distinguishing Electromagnetic Field Enhancement Effect from the Heating Effect
Ravi Teja Addanki Tirumala, Nishan Khatri, Sundaram Bhardwaj Ramakrishnan, Farshid Mohammadparast, Mohd Tauhid Khan, Susheng Tan, Phadindra Wagle, Sharad Puri, David N. McIlroy, Ali Kaan Kalkan, Marimuthu Andiappan
Abstract
Controlling and tuning activity and selectivity in catalysis are important for the development of energy-efficient and environmentally friendly catalytic processes for applications such as chemical synthesis, pollution mitigation, and energy conversion and storage. In that vein, plasmonic and dielectric Mie resonance-mediated photocatalyses have emerged as promising approaches. Although numerous reports in the past decade have shown the use of Mie resonances for tuning the catalytic activity, reports on the demonstration of tunable product selectivity are rather limited. Also, it remains a major challenge in the field to distinguish the desired Mie resonance-mediated electronic and electromagnetic field effects in photocatalysis from the undesired light-induced heating effect. Here, we distinguish the dielectric Mie resonance-mediated photocatalysis from the light-induced heating effect using single-particle Raman spectroscopy. We show that the photocatalytic activity and product selectivity on dielectric cuprous oxide (Cu 2 O) particles can be tuned by controlling the incident light intensity and wavelength. The conversion of methylene blue molecules into oligomerization and mineralization products is used as a probe reaction. Our findings signify that the utilization of light is a powerful means to control and tune the activity and selectivity in catalysis.