The purpose of this study is to search for effective dopants and their optimal combinations to improve the electrocatalytic activity of the SnO 2 electrode for the remediation of aqueous pollutants. For this purpose, Sb was selected as the primary dopant for SnO 2 and six elements (Fe(III), Ni(II), Co(II), Ru(III), Ce(III), and Pd(II)) were also introduced into the optimized Sb-SnO 2 electrodes. The electrodes were checked for their electrochemical properties at different doping levels and tested for their electrocatalytic activities for the degradation of phenol and Eosin Y. In addition, RNO (N,N-dimethyl-p-nitrosoaniline) was used as a probe molecule for OH radicals to examine the reaction mechanism occurring at the electrodes. Sb with a 5-10at.% was most effective in making SnO 2 an electrocatalyst and Ni (∼1%) enhanced the degradation rate and TOC removal rate of phenol at the Sb-SnO 2 anode by a factor of 14 and 8, respectively. Fe also increased the activity moderately. Enhanced Ni-Sb-SnO 2 activity was also found for Eosin Y. The other co-dopants exhibited various degrees of positive or negative effects depending on the substrate. The lack of a correlation in the kinetics between substrate degradation and the RNO changes indicated that the primary electrocatalytic reactions may proceed via direct electron transfer and/or organic peroxy radical-mediation, not OH radical-mediation. Detailed analyses of the electrode surfaces (SEM, TEM, XRD, and XPS) and quantification of intermediates were carried out to obtain insight into the heterogeneous electrocatalytic reaction.
- Water treatment
ASJC Scopus subject areas
- Process Chemistry and Technology
- Environmental Science(all)