Abstract
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•Novel plasmonic p-n heterojunction Ag/Ag2O/PbBiO2Br photocatalysts were fabricated.•The synergistic effect between the LSPR effect and the p-n heterojunction promotes charge separation and light absorption.•Ag/Ag2O/PbBiO2Br composites present excellent photoactivity for TC degradation under both visible and NIR light irradiation.•Ag/Ag2O/PbBiO2Br composites bring new insights into the construction of novel plasmonic p-n heterojunction photocatalysts.
Among several factors that influence the effectiveness of a semiconductor mediated photocatalysis, efficient charge separation and broadened light absorption are regarded as two of the most important parameters. Herein, a series of plasmonic p-n heterojunction Ag/Ag2O/PbBiO2Br photocatalysts with wide spectrum responses were successfully fabricated through a facile precipitation-calcination method. The obtained samples display exceptional photocatalytic performance for the degradation of tetracycline (TC), and the results reveal that the 10 wt% Ag/Ag2O/PbBiO2Br exhibits the optimal activity, which can efficiently decompose 84.4% of TC after 90 min of visible light irradiation. While under NIR light irradiation, the TC removal ratio can still reach 50.9% with 240 min. Besides, no significant deterioration in the degradation performance is observed even after four cycling runs. The photoactivity enhancement of Ag/Ag2O/PbBiO2Br can be credited to the synergistic effect between the local surface plasmon resonance (LSPR) effect of metallic Ag and the p-n heterojunction of Ag2O/PbBiO2Br, which not only greatly broadens the light utilization, but also remarkably accelerates the charge separation. The radical trapping experiments and the ESR measurements ascertains that O2−, h+ and OH play a critical role in the degradation of TC under visible light irradiation, while O2− and h+ become the major reactive species in NIR light-driven reaction. According to the experimental results, the plausible reaction mechanisms for TC degradation over Ag/Ag2O/PbBiO2Br composite are proposed under both visible and NIR light irradiation. This work provides some guidance for rational construction of novel plasmonic p-n heterojunction photocatalysts to meet ever-increasing environmental requirements.