RESUMO
As of the present time, the in-depth study of the structure-activity relationship between electronic configuration and CO2 photoreduction performance is often overlooked. Herein, a series of Cux species modified CeO2 nanodots are constructed in situ by flame spray pyrolysis (FSP) to achieve an efficient photocatalytic CO2-to-C2 conversion with an electron utilization of up to 142.5 µmol g-1. Through an in-depth study of the electronic behavior and catalytic pathways, it is found that the Cu0/Cu+ species in the coexistence state of Cu0/Cu+/Cu2+ can optimize the energy band structure, photocurrent stability, and provide a kinetic basis for the active surface catalytic reaction process that requires the conversion of multiple electrons into C2 products, which ultimately enhances the CO2-to-C2H6 photoreduction by 3.8-fold and that for CO2-to-C2H4 photoreduction by 5.2-fold. Besides, the Cu2+ species in the coexistence state of Cu0/Cu+/Cu2+ are able to regulate the electronic behavior and the choice of the catalytic pathway, enabling the transitions between CO2-to-C2H6 and CO2-to-C2H4. This work indicates that electronic configuration optimization is an effective strategy to significantly enhance the CO2 photoreduction performance and provides new ideas for the design and synthesis of high-performance heterostructure photocatalysts.
RESUMO
We designed and constructed rare earth doped upconversion nanoparticles ß-Na(Y0.78Yb0.18Er0.04)F4, sensitizing layer encapsulated ß-Na(Y0.9Er0.1)F4@ß-NaYbF4 and inert layer encapsulated ß-Na(Y0.9Er0.1)F4@ß-NaYbF4@ß-NaYF4. Compared with the mononuclear material, the luminescence intensity of the particles encapsulated with double shells in the three main bands of blue, green and red emissions increased by 346, 22, and 54 times respectively. While improving the upconversion luminescence performance, the underlying reasons for this improvement were analyzed in detail. The effects of shell coating on the fluorescence lifetime, thermal stability and energy level transition are discussed. On this basis, the composite film material was constructed by combining the shell coating strategy and the plasma resonance interaction strategy, which further improved the upconversion efficiency. In addition, by combining performance optimized upconversion particles with information coding, we explored its potential as an anti-counterfeiting material.