ZnO nanostructures decorated with gold nanoparticles (Au-NPs) were synthesized by thermal decomposition of ZnO₂ powders and their subsequent impregnation of metal nanoparticles using either the Direct Turkevich Method, the Inverse Turkevich Method, or the Progressive Heating Method. It was found that the impregnation approach influences the resulting microstructure and photocatalytic activity of the obtained materials. While the Direct Turkevich approach gave the highest yield of metal loading, the smallest Au-NPs were obtained by Inverse Turkevich and the Progressive Heating Method. The photocatalytic activity of the pristine support and gold-loaded samples was studied in the decolorization of Rhodamine B solutions using UV- and pure visible-light illumination. All Au-NPs/ZnO samples showed higher photocatalytic activity than the bare support when UV-light was used. This effect is attributed to a charge carrier separation due to electron transfer from ZnO to the metal nanoparticles and the built-in electric field at the interfaces. Contrarily to most reports, visible-light sensitization using plasmonic nanoparticles was not observed. The experimental evidence points against hot-electron injection from Au-NPs to the semiconductor component. This behavior is associated with the height of the Schottky barrier at the metal-semiconductor junctions. The differences in the photocatalytic performance among the samples under UV- and visible-light are explained in terms of the characteristics of the Au-NPs driven by the growth mechanism involved in each impregnation method and the physicochemical properties of the generated interfaces.

Aflatoxin B1 (AFB₁) is one of the most dangerous mycotoxins found in food, necessitating the development of precise and reliable methodologies for its detection. In this study, a novel electrochemical sensor based on a molecularly imprinted polymer (MIP) integrated with a carbon-paste electrode was developed for the voltammetric determination of AFB₁. The innovative aspect of this work lies in the use of methacrylic acid (MAA) as the functional monomer, which enhances the sensor’s selectivity and binding affinity. The developed electrochemical sensor exhibited a linear response range from 20.8 to 80 ng/L, with a limit of detection (LOD) of 2.31 ng/L and a sensitivity of 19.83 µA (ng/L)⁻¹ cm⁻². The sensor demonstrated outstanding analytical performance, with reproducibility and repeatability yielding relative standard deviations (RSDs) of 3.24% and 1.41%, respectively. To validate the sensor’s practical applicability, its performance was tested in real samples of corn and wheat using the standard addition method. Samples were prepared following official Mexican standard methods. Detected AFB₁ concentrations were 0.0147 μg/L and 0.0138 μg/L for corn and wheat, respectively. A statistical comparison using the Student’s t-test confirmed no significant matrix effects, underscoring the high selectivity and accuracy of the MIP-modified sensor. This work introduces a highly selective, sensitive, and reproducible methodology for AFB₁ detection, which could significantly advance food safety monitoring.

Objective: The objective of this research work is to determine the viability of using passive cooling in photovoltaic systems that operate in the metropolitan area of Pachuca, Mexico, taking advantage of the strong gusts in the region and thereby increasing the generation of energy produced. Theoretical Framework: This research is based on principles such as the principle of conservation of energy, specifically referring to heat transfer, the law of entropy, and the photogeneration of electric current. Method: The experimental strategy used to carry out this research consisted of three stages. In the first, experimental measurements were carried out using a Davis Vantage Pro2 Plus model weather station in a period that spanned from May 19, 2019, to September 21, 2021. The second stage consisted of processing the data to obtain the maximum, average and minimum values of wind speeds in the region and with it, the temperatures and irradiances corresponding to said values. Finally, the third stage consisted of carrying out computational simulations of external flow and heat transfer in the geometries previously developed for this purpose. Results and Discussion: The results obtained showed that during the autumn months the wind speed allows the performance of the photovoltaic systems to be increased by a maximum of 11.22%. However, this value is drastically reduced in the spring months when the wind speed reduces to around 4% of the maximum speed. Research Implications: The results of this research can be used in the design of photovoltaic generation systems in the metropolitan area of Pachuca, which extends to the municipalities of Mineral de la Reforma, Zempoala, Mineral del Chico and San Agustín Tlaxiaca. Likewise, it allows us to begin research into the solar energy potential of the region and its potential future use. Originality/Value: The region is characterized by receiving high sunshine according to data from the Mexican Center for Innovation in Solar Energy and the Solar Radiation Observatory belonging to the National Autonomous University of Mexico. However, practical research applied to this field of study is limited to the measurement of meteorological values. This study contributes to the state of the art by providing reference conditions for the operation of photovoltaic systems in the state of Hidalgo.