Search results for " solar irradiation"

La1-xSrxCo1-yFeyO3-delta perovskites: Preparation, characterization and solar photocatalytic activity

2015

Abstract LaCoO3 perovskites substituted by Sr at the A site and/or by Fe at the B site have been prepared by the citrate method. Characterizations by several techniques, such as specific surface area (BET method), XRD, TPR, SEM, UV–vis in DRS mode, XPS and TGA analyses, have been performed. The so prepared La1−xSrxCo1−yFeyO3−δ perovskites are semiconductor materials showing band gap energy values from 1.9 to 3.2 eV. They displayed solar photocatalytic activity for the 2-propanol degradation in gas–solid regime. The photocatalytic results suggest that the perovskites containing Fe are less active and the activity decreases by increasing the Fe content, however the presence of iron avoids the…

Cu-substituted lanthanum ferrite perovskites: Preparation, characterization and photocatalytic activity in gas-solid regime under simulated solar lig…

2016

Lanthanum orthoferrites LaFeO3 nanopowders doped with 20 mol% of Sr and 0-10-20 mol% of Cu were prepared by citrate auto-combustion synthesis and investigated in terms of crystal structure, morphology, surface area and optical properties by using several characterization techniques. The band gap energy values were found to range from 2.35 eV for LaFeO3 to 1.86 eV for the samples with the highest content of copper, this trend reflects the decrease of the particle size. All powders showed photocurrent response, the highest photocurrent was obtained for undoped orthoferrite calcined at 600°C. Their physical-chemical properties were related to photoelectrochemical behaviour. The the position of…

Relationship between erythemal UV and broadband solar irradiation at high altitude in Northwestern Argentina

2018

An analysis of the broadband solar irradiation, IT, and the erythemal UV irradiation, IUVER, has been performed using the measurements made from 2013 to 2015 at three sites located at altitudes over 1000 m a.s.l. In Northwestern Argentina (Salta, El Rosal, and Tolar Grande). The main objective of this paper is to determine a relationship between IT and IUVER, which would allow to estimate IUVER from IT in places with few IUVER measurements available, and especially in those where is important to establish adequate photoprotection measures given their dense population and location at high altitude. The relationship between the daily values of IUVER and IT has been fitted to a linear regressi…

Photoactivity of Shape-Controlled TiO2 in Gas-Solid Regime Under Solar Irradiation

2018

Shape-controlled TiO2 materials have been tested as photocatalysts under both simulated and natural solar irradiation.

N-Doped Anatase/Rutile Photocatalysts for the Synthesis of Aromatic Aldehydes Under Ultraviolet and Solar Irradiation

2015

N-doped anatase/rutile photocatalysts were prepared by a sol-gel method, using TiCl4 as TiO2 precursor and urea as N-dopant source. The catalysts required a thermal treatment at temperature higher than 300 degrees C to achieve actual nitrogen doping; this treatment also allowed obtaining crystalline and hydrophobic samples. Moreover, nitrogen doping modified the surface of samples by increasing the anatase to rutile phase ratio and hydrophilicity. The catalysts were characterized by BET specific surface area, XRD, ESEM, TGA, FT-IR, DRS and XPS measurements, with particular attention to the assessment of the N-doping effect. It was found that XPS analysis should be used together with DRS and…

Enhancing Selectivity of Photocatalytic Synthesis of p-Anisaldehyde in Water under Solar Irradiation by N- Doped TiO2

2014

A Dynamic Electrical Scheme for the optimal reconfiguration of PV modules under non-homogeneous solar irradiation

2012

This paper presents a strategy for the maximization of the output power of photovoltaic (PV) systems under non homogeneous solar irradiation by means of automatic reconfiguration of the PV arrays layout. The innovation of the proposed approach is the employment of a simple Dynamic Electrical Scheme (DES), allowing a large number of possible modules interconnection, to be installed between the PV generator and the inverter. The models of the PV generator and of the DES have been realized and simulated with Simulink (Dynamic System Simulation for MATLAB). The attained experimental results appear to be quite interesting in terms of the attainable benefit in power and thus energy terms. The lim…