Constructing ultralow-loading Cu single atoms/Fe2O3 particles on Nb2C MXenes for efficient utilization of atomic H to boost electrochemical debromination

Abstract

Bromate is a commonly identified carcinogenic and genotoxic disinfection byproduct in water. Electrochemical debromination is an environmentally friendly and effective approach but it often suffers the limited reducing atomic H (H*) ability and high metal catalyst dosage. In this study, a unique composite catalyst comprised of ultra-low loading Cu single atoms (0.016 wt%) and Fe2O3 nanoparticles supported on a Nb2C MXene (denoted as Cu0.2/Fe0.1/Nb2C) was synthesized by one-step high-temperature molten salt method. The Cu0.2/Fe0.1/Nb2C significantly outperformed the Nb2C, Cu0.2/Nb2C and Fe0.1/Nb2C counterparts in the electrochemical debromination with a 94.2 % removal efficiency of bromate. It is revealed that the introducing of Cu single atoms, efficiently promotes the adsorption of H* and inhibition of competitive H2 evolution. The incorporation of Fe2O3 nanoparticles significantly increased the electronic metal-support interaction effect between the metal components and Nb2C, thereby forming a noticeable electronic cloud bridge to facilitate efficient charge transfer. Ultimately, the synergistic interplay between Cu single atoms and Fe2O3 nanoparticles plays a crucial role in achieving the remarkable removal performance of bromate. This work not only presents a significant instance of a synergistic catalyst involving metal single atoms and metal nanoparticles for effective electrochemical debromination but also advances the understanding of the electronic metal-support interaction.