The engineering of surface plasmon resonance and up-conversion to improve the photocatalytic performance of MIL-53(Fe) over the full solar spectrum

A novel ternary composite (Ag/CQDs/MIL-53(Fe)) with full-spectrum absorption and high photocatalytic activity was successfully synthesized for the first time. The combination between up-conversion effects of the carbon quantum dots (CQDs) and the surface plasmon resonance (SPR) effects of the Ag NPs synergistically boosts the absorption over the full solar spectrum of the Ag/CQD/MIL-53(Fe) composite. The synergistic effects of Ag NPs, CQDs and MIL-53(Fe) can effectively increase the charge separation and transfer rates. 15-Ag/CQDs/MIL-53(Fe) displayed the best photocatalytic activity, for which could degrade methylene blue at a rate of up to 93.05% within 120 min under simulated sunlight. In addition, 15-Ag/CQDs/MIL-53(Fe) has 75.75%, 76.42% and 41.48% degradation rates for MB under UV light, visible light and infrared light, respectively. The above experimental results show that Ag/CQDs/MIL-53(Fe) composite has high photocatalytic degradation efficiency over the whole solar spectrum. In addition, the charge transfer processes in the Ag/CQDs/MIL-53(Fe) degradation of organic pollutants were also deduced.