Photocatalytic and Conductivity Studies of Proton Exchanged Defect Pyrochlore, KMn0.33Te1.67O6 and its Application in Pb2+ Removal

Ion-conducting oxide materials have incredible technological importance, particularly in devices such as sensors, fuel cells and steam electrolysis cells. In this work, a new proton exchanged defect pyrochlore, HMn0.33Te1.67O6 (HMnTeO), was synthesized by ion-exchange method at room temperature by dissolving KMn0.33Te1.67O6 (KMnTeO) in 5 M HCl solution for 48 h. It was thoroughly characterized by powder-XRD, FESEM-EDX, TEM-HRTEM, FT-IR, Raman, TGA, UV-Vis DRS, PL and XPS techniques. The photocatalytic and DC conductivity of HMnTeO were compared with parent KMnTeO material. The protonated form (HMnTeO) exhibits higher photocatalytic activity against methylene blue degradation and superior DC conductivity compared to parent KMnTeO. The participation of radical species in dye degradation was investigated through scavenger and terephthalic experiments. Based on the results obtained, a probable mechanism was also proposed. Removal of Pb2+ ions from aqueous Pb(NO3)2 was also accomplished using parent KMnTeO.