Insights into the origin of super-high oxygen evolution potential of Cu doped SnO2 anodes: A theoretical study

Abstract

SnO2 based anodes have been recognized as the most promising anodes for wastewater treatment due to the high oxygen evolution potential, high current efficiency and low cost. Herein, using large-scale screening-based density functional theory, we systemically investigate the origin of super-high oxygen evolution potential of Cu doped SnO2 anodes. We find that the low binding energy of OH* on (1 1 0) plane of Cu doped SnO2 anodes leads to the high onset potential for oxygen evolution. Detailed calculations of bond configurations and valence electron numbers reveal that the weak chemical absorption of OH* contribute to the low binding energy. The theoretical onset potential of oxygen evolution of 2.639 V (vs RHE) obtained from Free-energy diagram for OERs agrees well with the experimental value of ∼2.7 V (vs RHE).