RESUMEN
In this study, the 2D porous graphitic carbon nitride (g-C3N4) nanosheets were successfully fabricated via a facile thermal decomposition polymerization method without any help of templates, and then novel porous g-C3N4/CdS complex catalysts of different mass fractions were is situ synthesized by a simple solvothermal process. The results of photocatalytic experiments demonstrate that the coupling g-C3N4/CdS cocatalysts exhibit significant enhanced visible-light-driven photocatalytic activity for the decolorization of methyl orange (MO) compared with individual porous g-C3N4 and CdS. In particular, an optimal porous g-C3N4 content in the hybridized composite has been determined to be 70 wt.%, corresponding to pseudo-first-order rate constant of 0.046 min-1, which is 7 and 11 times faster than that of pure porous g-C3N4 and CdS, respectively. Photoluminescence (PL) spectroscopy measurements clearly confirmed that the recombination of photoproduced electrons and holes in g-C3N4/CdS composites was efficiently inhibited due to the formation of heterojunctions. Furthermore, the possible mechanism of enhanced photocatalytic activity and photostability of prous g-C3N4/CdS are also tentatively proposed.
RESUMEN
Hierarchical SnO2 blooming nanoflowers were successfully fabricated via a simple yet facile hydrothermal method with the help of different surfactants. Here we focus on exploring the promotion effects of surfactants on the self-assembly of 2D SnO2 nanosheets into 3D SnO2 flower-like structures as well as their gas-sensing performances. The polyporous flower-like SnO2 sensor exhibits excellent gas-sensing performances to ethanol and H2S gas due to high porosity when polyvinyl pyrrolidone is added into the precursor solution as a surfactant. The response/recovery times were about 5 s/8 s for 100 ppm ethanol and 4 s/20 s for 100 ppm H2S, respectively. Especially, the maximum response value of H2S is estimated to be 368 at 180 °C, which is one or two orders of magnitude higher than that of other test gases in this study. That indicates that the sensor fabricated with the help of polyvinyl pyrrolidone has good selectivity to H2S.