Applied Catalysis B: Environmental, Vol.237, 473-481, 2018
Construction of a bifunctional electrode interface for efficient electrochemical mineralization of recalcitrant pollutants
To further improve the electrochemical performance of a boron-doped diamond (BDD) electrode, a two-dimensional, macroporous, Sb-doped SnO2 film is constructed on BDD to obtain a bifunctional electrode interface (denoted Mp-SnO2/BDD) with an ordered, monolayer, photonic-crystal template using a sol-gel method. SEM images confirm that the SnO2 film consisted of innumerable, uniform, nanosized SnO2 particles and numerous macropores with diameters of 200-300 nm, and some BDD polycrystallites are exposed in those macropores. The microstructure endows Mp-SnO2/BDD with a high oxygen evolution potential (2.23 V), good conductivity (175 O), and excellent electrocatalytic activity. To evaluate the degradation capability, the electrocatalytic oxidation of a high concentration of clofibric acid (CA) is studied in detail. The CA and chemical oxygen demand (COD) removals on Mp-SnO2/BDD are above 90% after 240 min. The degradation rate constant on Mp-SnO2/BDD is 1.6 times that on BDD. Compared with BDD and traditional SnO2/Ti, Mp-SnO2/BDD exhibites a higher instantaneous current efficiency and lower electrochemical energy consumption. In addition, we qualitatively and quantitatively analyze the intermediates in the degradation process and proposed three possible oxidative decomposition pathways for CA. Mp-SnO2/BDD is expected to be a promising anode for organic wastewater treatment.