Enhanced photocatalytic performance of Ag-BiOBr nanosheets under LED with different wavelengths

The surface deposition of noble metals can effectively improve photocatalytic performance by the effect of electron trapping (ET) or surface plasmon resonance (SPR), but it is not clear which effect dominates the photocatalytic degradation of organic dyes under light irradiation at specific wavelengths. In this work, a series of xAg-(1-x)BiOBr (x = 0.01, 0.02, 0.03, 0.04, 0.05, and 0.06) nanosheets were synthesized via an ultrasonic-assisted chemical coprecipitation and photo-deposition reaction. The effect of light-emitting diode (LED) with different wavelengths on the photocatalytic degradation of Rhodamine B (RhB) dye was investigated. The results revealed that the hole (h⁺) and superoxide free radical (O₂˙^-) of xAg-(1-x)BiOBr were the main reactive groups contributing to the rapid decomposition of RhB dye. However, it is worth noting that the sources of the main active groups under LED with different wavelengths were different. Notably, photocatalytic performance was enhanced by the ET effect or SPR effect of Ag particles under LED of 390 nm or 570 nm, respectively. Moreover, both the ET and SPR effects synergistically enhanced the photocatalytic performance of Ag-BiOBr under full-spectrum irradiation (xenon lamp). This work provides theoretical and experimental insights into noble metal deposition modification and accelerates the application of photocatalysis technology in the degradation of printing and dyeing wastewater.