Photoinduced reactivity of titanium dioxide

Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases

We show for the first time that the photogenerated hole lifetime in TiO2 is a strong determinant of the ability of TiO2 to split water. Hole lifetimes were measured using transient absorption spectroscopy over a range of excitation intensities. The lifetimes of the holes were modulated by the use of exogenous scavengers and were also found to vary systematically with the excitation intensity. In all cases the quantum yield of oxygen production is found to be linked to the light intensity used, ranging from below 1 sun equivalent to nearly 1 sun equivalent. We also provide evidence that oxygen production requires four photons for each molecule of oxygen, which is reminiscent of the natural photosynthetic water-splitting mechanism. This in turn suggests a mechanism for oxygen production which requires four-hole chemistry, presumably via three, as yet unidentified intermediates. It is also shown that at excitation densities on the order of 1 sun, nongeminate electron−hole recombination limits the quantum yie...

Mechanism of photocatalytic water splitting in TiO2. Reaction of water with photoholes, importance of charge carrier dynamics, and evidence for four-hole chemistry.

The role of active oxygen species in the photocatalytic bactericidal effect was investigated using a thin transparent titanium dioxide (TiO2) film. The viable number of Escherichia coli (E. coli) significantly decreased on the illuminated TiO2 film, and the bactericidal effect was observed even when E. coli was separated from the TiO2 surface with a 50 μm porous membrane. Mannitol, a hydroxyl radical scavenger, inhibited the effect only in the absence of the membrane. In contrast, catalase inhibited the effect in all cases. On the basis of these results, the long-range bactericidal effect of hydrogen peroxide was proposed, together with a cooperative effect due to other oxygen species. © 1997 Elsevier Science S.A.

Photocatalytic bactericidal effect of TiO2 thin films : dynamic view of the active oxygen species responsible for the effect

Solar/UV-induced photocatalytic degradation of three commercial textile dyes.

Photosynthetic production of H2 and H2O2 on semiconducting oxide grains in aqueous solutions

Photosynthetic production of hydrogen and hydrogen peroxide on semiconducting oxide grains in aqueous solutions

The automation of daily routine tasks is day-by-day increasing. This is a necessary scenario, especially in today's lifestyle. One such automation is driverless vehicle driving which requires the prompt identification of the potholes present on the roads. A lot of research is present to deal with the real-time pothole identification challenges. However, none of the existing research is capable of achieving prompt accurate prediction. To contribute to the existing literature, this paper proposes a Dark Convolutional Neural Network (Darknet CNN) based model called tiny YOLO (You Only Look Once) for pothole identification and dimension approximation of the potholes in order to alert the driver (or automation system) for the safe driving. The proposed model is implemented for the number of epochs to check the performance of the model. The performance metric used for the model evaluations includes Precision (P), Recall (R), Average Precision (AP), and micro Average Precision (mAP) as evaluation criteria with low GPU memory utilization, bounding box area, object Area, and total area. The model gives the best performance for the 270 epochs. The proposed model is light weighted, which helps the video to store in minimum space and lesser time span.

M. V. Rao

Papers

Photosynthetic production of H2 and H2O2 on semiconducting oxide grains in aqueous solutions

Photosynthetic production of hydrogen and hydrogen peroxide on semiconducting oxide grains in aqueous solutions

Pothole Identification and Dimension Approximation with YOLO Darknet CNN