RESUMEN
Efficient separation of photogenerated electron-hole pairs is always one of the key factors boosting visible light photodegradation efficiency. Till now, there are few reports on the synergistic competitive consumption of photogenerated active species and the synergistic adsorption of organic contaminants to promote the performance of a designed heterojunction. Herein, we design and construct a novel BiOBr/Ag6Si2O7 heterojunction with the dual synergistic effects towards methylene blue (MB) and methyl orange (MO). The dual synergistic effects could avoid the combination of photogenerated h+/e- pairs, improve the adsorption efficiency, and even regulate the photodegradation efficiency. Thus, for an aqueous mixture of MB and MO, the BiOBr/Ag6Si2O7 photocatalyst exhibits largely improved adsorption capacities of the dyes by a multi-layer adsorption mode. Moreover, the photocatalyst could further promote the photodegradation rate of MO while slow that of MB due to the competitive consumption of photogenerated active species, showing a sequential selectivity phenomenon. Thanks to the dual synergistic effects, the adsorption capacity of MO increases 1379% higher than that of neat MO solution, and the photodegradation time decrease from 30 to 12â¯min with a rate constant of 0.22â¯min-1, 38% higher than that of neat MO solution.
RESUMEN
The smaller particle sizes, better dispersion, and more heterojunction interfaces can enhance the photocatalytic performance of photocatalysts. Herein, ultradispersed amorphous silver silicates/ultrathin g-C3N4 nanosheets heterojunction composites (a-AgSiO/CNNS) with intimate interfacial coupling effect were synthesized through the facile in situ precipitation of ultrafine a-AgSiO (â¼5.2 nm) uniformly dispersed on the entire surface of hierarchical ultrathin CNNS. In this process, the ultrathin CNNS not only perform as the support to form heterostructures but also are employed as dispersant to confine the aggregation of a-AgSiO nanoparticles. Notably, the optimum photocatalytic activity of a-AgSiO/CNNS-500 composite is â¼36 and 13 times higher than that of CNNS toward the degradation of rhodamine B and tetracycline, respectively. The excellent photocatalytic activity can be attributed to the synergistic interactions of heterojunction with strong interfacial coupling effect, improved visible light absorbance, abundant heterojunction interfaces, and fully exposed reactive sites, which originate from the well-defined nanostructures such as uniform packing of the ultrasmall a-AgSiO, the intimate and maximum coupling interfaces between a-AgSiO and CNNS. We believe that such an easy and scalable synthetic strategy can be further extended to the fabrication of other ultrafine semiconductors coupled with g-C3N4 for increasing its photocatalytic performance.