Core-shell CeO2@C60 hybrid serves as a dual-functional catalyst: Photocatalyst for organic pollutant degradation and electrocatalyst for oxygen evolution reaction

Abstract

Due to energy crises and environmental pollution worldwide, researchers have sought efficient electrocatalysts for oxygen evolution reaction (OER) and photocatalysts to eliminate organic pollutants. In the present work, we have synthesized a fullerene-C60-based CeO2@C60 core-shell hybrid and characterized it with various state-of-art techniques to explore its OER performance and photocatalytic properties under natural sunlight. TEM nano-graphs and EDX color mapping exhibited the uniform covering of C60 over CeO2 forming a core-shell structure with a particle size of 54 nm. The XPS results demonstrate the coexistence of Ce3+ and Ce4+ oxidation states, resulting in the formation of rich oxygen vacancy defects, which induced the efficient charge transformation from CeO2 to C60, enhancing the photocatalytic activity and promoting the OER reaction. The electrochemical measurements revealed a lower overpotential (312 mV) and small Tafel slope (54 mV/dec) at 10 mA/cm2 current density of CeO2@C60 core-shell hybrid than pure CeO2. Further, the hybrid is stable up to 2000th cycles, and the chronoamperometry test showed that it remains stable for 45 hr without degrading in 1 M KOH solution. The photocatalytic activity under natural sunlight irradiations showed that the CeO2@C60 core-shell hybrid completely degraded P-nitroaniline (P-Nitro) organic pollutant after 75 min, with outstanding recyclability up to the 7th cycle of use. Furthermore, the present work explores the tremendous potential of C60 and rare earth metal oxide-based hybrid catalysts having exceptional stability toward photocatalysis and electrochemical water splitting.