Fabrication of SnO2/TiO2 composite by a chemical co-precipitation method for efficient electrocatalytic oxidation of methylene blue

Abstract

In the present research, the Tin dioxide/Titanium dioxide (SnO₂/TiO₂) composite has been successfully fabricated by a chemical co-precipitation method. SnO₂/TiO₂ composite precursors were calcined at different temperatures (400 °C, 500 °C 600 °C, 700 °C). The degradation experiment of methylene blue (MB) dye using SnO₂/TiO₂ composite material was conducted to analyze the electrocatalytic performance. The degradation efficiency of the composite material can reach 96.6% (calcination at 500 °C). The logarithm of methylene blue concentration exhibits a strong linear relationship with reaction time, and the correlation coefficient R for each curve exceeds 0.99. This suggests that the electrocatalytic degradation process of methylene blue follows quasi-first order reaction kinetics. The ⋅OH present in the whole system can oxidize methylene blue (MB) into CO₂ and H₂O, and the reaction is accompanied by oxygen evolution reaction. The inactive electrode has weak adsorption to the free ⋅OH, so the SnO₂/TiO₂ electrode in the system has obvious advantages. The composite material electrode calcinated at 500 °C has the fastest electrocatalytic decolorization reaction rate and the highest catalytic capacity, which is consistent with the results of degradation efficiency.

Graphical abstract