Influence of anatase and rutile phase in TiO2 upon the photocatalytic degradation of methylene blue under solar irradiation in presence of activated carbon.

The influence of activated carbon (AC) on the photocatalytic activity of different crystalline TiO2 phases was verified in the photocatalytic degradation of methylene blue under UV and solar irradiation. The results showed a volcano trend with a maximum photoactivity for the crystalline phase ratio of anatase:rutile equal to 80:20 both under UV or solar irradiation. By contrast, in presence of AC the photocatalytic activity of the binary materials of TiO2/AC followed an exponential trend, increasing as a function of the increase in anatase proportion in the TiO2 framework. The increase in the photoactivity of the binary material TiO2/AC relative to neat TiO2 was up to 22 and about 17 times higher under UV and visible irradiation, respectively. The present results suggest that AC interacts more efficiently with anatase phase than with rutile phase.

Optimal strategy to certify quantum nonlocality.

Certification of quantum nonlocality plays a central role in practical applications like device-independent quantum cryptography and random number generation protocols. These applications entail the challenging problem of certifying quantum nonlocality, something that is hard to achieve when the target quantum state is only weakly entangled, or when the source of errors is high, e.g. when photons propagate through the atmosphere or a long optical fiber. Here we introduce a technique to find a Bell inequality with the largest possible gap between the quantum prediction and the classical local hidden variable limit for a given set of measurement frequencies. Our method represents an efficient strategy to certify quantum nonlocal correlations from experimental data without requiring extra measurements, in the sense that there is no Bell inequality with a larger gap than the one provided. Furthermore, we also reduce the photodetector efficiency required to close the detection loophole. We illustrate our technique by improving the detection of quantum nonlocality from experimental data obtained with weakly entangled photons.