Roles of CeO2 in preparing Ce-doped CdIn2S4 with boosted photocatalytic degradation performance for methyl orange and tetracycline hydrochloride

Element doping is considered as a feasible strategy to develop efficient photocatalysts. In this study, a Ce-doped CdIn2S4 photocatalyst was prepared through a modified coprecipitation method. During the synthesis of Ce-doped CdIn2S4, the CeO2 nanorods were gradually reduced by the decomposition products of thioacetamide (TAA), and mainly existed as Ce(III) in the supernatant. This resulted in a large increase in the specific surface area of the as-obtained products, providing more exposed active sites for the reactant. Additionally, a trace amount of Ce was doped into the lattice of the CdIn2S4, resulting in a significant effect on the band structure. By tracing the roles of CeO2 during the synthesis process, a possible reaction mechanism was proposed. Benefiting from the synergistic advantages of the structural and compositional features, the optimal sample showed enhanced photocatalytic activities for the degradation of methyl orange (94.6% within 25 min) and tetracycline hydrochloride (85.6% within 120 min). The degradation rates were 13.3 times and 2.7 times higher than that of pristine CdIn2S4. This work may provide a strategy for designing metal element doped photocatalysts with good activity for pollutant removal.