Facile Synthesis, Characterization, and Photocatalytic Evaluation of In₂O₃/SnO₂ Microsphere Photocatalyst for Efficient Degradation of Rhodamine B

The tin dioxide (SnO2) photocatalyst has a broad application prospect in the degradation of toxic organic pollutants. In this study, micron-sized spherical SnO2 and flower indium oxide (In2O3) structures were prepared by a simple hydrothermal method, and the In2O3/SnO2 composite samples were prepared by a “two-step method”. Using Rhodamine B (RhB) as a model organic pollutant, the photocatalytic performance of the In2O3/SnO2 composites was studied. The photocurrent density of 1.0 wt.% In2O3/SnO2 was twice that of pure SnO2 or In2O3, and the degradation rate was as high as 97% after 240 min irradiation (87% after 120 min irradiation). The reaction rate was five times that of SnO2 and nine times that of In2O3. Combined with the trapping experiment, the transient photocurrent response, and the corresponding characterization of active substances, the possible degradation mechanism was that the addition of In2O3 inhibited the efficiency of electron–hole pair recombination, accelerated the electron transfer and enhanced the photocatalytic activity.