Photocatalytic degradation of methyl orange by Ag/TiO2/biochar composite catalysts in aqueous solutions

One set of biochar-coupled Ag and TiO2 composites were successfully fabricated by mixing, calcination, and photodeposition method to remove methyl orange (MO). It was found that all catalysts modified with Ag showed better photocatalytic degradation performance (the highest decolorization efficiency and mineralization efficiency were 97.48% and 85.38%, respectively) than single TiO2 because of the synergy of Ag, TiO2 and biochar. Characterization results indicated that Ag as well as TiO2 acted as electron donor and biochar acted as electron acceptor, which could effectively promote the separation of photogenerated electron hole pairs. In addition, the catalyst exhibited high stability up to 5 cycles and the loss of activity was negligible. And the catalytic degradation process was consistent with the pseudo-first-order kinetic (PFOK) model with the degradation rate constant of 6.29 × 10−2 min−1.