The H₂O@HKUST‐1 and DMF@HKUST‐1 systems were experimental and computationally assessed, employing XRD/TGA/FT‐IR/DFT‐calculations, evidencing that H₂O or DMF coordinated to Cu, modulating HKUST‐1 photocatalytic properties. DMF@HKUST‐1 has narrower bandgap promoting higher‐crystallinity and light‐harvesting. H₂O@HKUST‐1 showed smaller particle sizing and sharp morphology. Theoretical models, (H₂O)₁@HKUST‐1 and (DMF)₁@HKUST‐1, containing one coordinated molecule, elucidated bandgap modulation associated with infiltration. H₂O@HKUST‐1/DMF@HKUST‐1 presented bandgaps [eV] of 3.6/3.4, by Tauc plots, and 3.55/3.26, by theoretical calculations, narrowing bandgap, compared with non‐solvated HKUST‐1(HKUST‐1_NS). Both composites raised the valence band (VB) and lowered the conduction band (CB), but DMF@HKUST‐1 most raised VB. Topological analysis revealed that guests i) with higher electronic density, raised VB, and ii) induced π‐backbonding, lowering CB. DMF@HKUST‐1 presented a higher photocatalytic hydrogen evolution (μmol), 26.45, in the first 30 min of the reaction, nevertheless, H₂O@HKUST‐1 presented a competitive activity, of 17.32. In large periods, H₂O@HKUST‐1/DMF@HKUST‐1 showed practically the same hydrogen evolution, 45.50/49.03.

The HKUST-1 and related MOFs have been proposed as photocatalysts, nevertheless they presented certain limitations, e.g. poor visible light absorption. Thus, we propose the encapsulation of the photosensitizer curcumin (Cur) in HKUST-1 as a strategy to improve light absorption in the resultant Cur@HKUST-1 composite. The Cur@HKUST-1 was characterized by XRD, FTIR, TGA, UV-Vis, BET, SEM, and electrochemical experiments confirming the Cur infiltration in 2.5%, preserving crystalline structure of HKUST-1. DFT calculations for Cur@HKUST-1 in periodic boundary conditions were employed to elucidate the chemical structure, corroborating experimental evidence. Chronoamperometry experiments in dark and visible light irradiation showed 48% photocurrent density enhancement for Cur@HKUST-1 vs. HKUST-1, corroborating the sensitization effect derived from Cur inclusion. As a result, Cur@HKUST-1, presented 1.2 times (20% higher) photocatalytic hydrogen evolution than free HKUST-1 under visible light irradiation, just by 2.5% Cur loading into the HKUST-1, demonstrating infiltration as a suitable, nonlinear, strategy to produce active MOFs for photocatalytic purposes.

The objective of this study was to analyze the impact of solar and hybrid dryers on the physicochemical characteristics, fingerprints, and cognitive-sensory perceptions of Mexican consumers of traditional tostadas made with corn of different races. Corn tostadas from different native races were evaluated with solar and hybrid (solar-photovoltaic solar panels) dehydration methods. Proximal chemical quantification, instrumental analysis (color, texture), fingerprint by Fourier transform infrared spectroscopy (FTIR), and sensory-cognitive profile (emotions and memories) and its relationship with the level of pleasure were carried out. The data were evaluated using analysis of variance models, Cochran Q, and an external preference map (PREFMAP). The results showed that the drying method and corn race significantly (p < 0.05) affected only moisture content, lipids, carbohydrates, and water activity. Instrumental color was influenced by the corn race effect, and the dehydration type influenced the fracturability effect. FTIR fingerprinting results revealed that hybrid samples exhibited higher intensities, particularly associated with higher lime concentrations, indicating a greater exposure of glycosidic or protein structures. Race and dehydration type effects impacted the intensity of sensory attributes, emotions, and memories. PREFMAP vector model results revealed that consumers preferred tostadas from the Solar-Chiquito, Hybrid-Pepitilla, Hybrid-Cónico, and Hybrid-Chiquito races for their higher protein content, moisture, high fracturability, crunchiness, porousness, sweetness, doughy flavor, corn flavor, and burnt flavor, while images of these tostadas evoked positive emotions (tame, adventurous, free). In contrast, the Solar-Pepitilla tostada had a lower preference because it was perceived as sour and lime-flavored, and its tostada images evoked more negative emotions and memories (worried, accident, hurt, pain, wild) and fewer positive cognitive aspects (joyful, warm, rainy weather, summer, and interested). However, the tostadas of the Solar-Cónico race were the ones that were most rejected due to their high hardness and yellow to blue tones and for evoking negative emotions (nostalgic and bored).

This research reports the development of photocatalytic active composites for hydrogen evolution obtained through high-energy mechanical milling of a mixture of the organic semiconductor g-C₃N₄ (CN) and the metal–organic framework ZIF-67. These composites, called CNZ-x (X = mass proportion of ZIF-67), were characterized using powder XRD, which showed that the crystalline phases of both the g-C₃N₄ and ZIF-67 precursors are present in the composites. SEM was used to determine the morphology, revealing that the ZIF-67 octahedral particles adhere to the surface of the CN sheets due to the intimate interfacial contact induced by high-energy mechanical grinding. The results of the photocatalytic evolution of H₂ indicate that the CNZ-50 composite produced 261 μmol g⁻¹ of H₂, which is higher than the 229.5 and 124 μmol g⁻¹ produced by the precursors ZIF-67 and CN, respectively. The higher efficiency in H₂ evolution is due to the composite having better electron-hole separation than the precursor materials.

We report the study of Cur@HKUST-1 composites, obtained through one-pot infiltration of HKUST-1 with curcumin (Cur) as a guest-sensitizing molecule. Cur features a HOMO energy above the valence band (VB) of HKUST-1, enabling modulation of the electronic structure of the host framework by introducing additional energy states within the bandgap. Structural characterization, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), confirmed successful guest incorporation and preservation of HKUST-1 crystallinity. An initial Cur amount of 50% (relative to the BTC linker) was added to the synthetic mixture, and differential UV-vis analysis has shown an infiltration efficiency of 28.0%, corresponding to an infiltration degree of 14% in the Cur@HKUST-1 composite, highlighting a challenging loading process, primarily due to the size and conformations of the Cur structure. Textural analysis revealed a reduction in surface area and pore volume, consistent with a high degree of guest infiltration. Optical properties evaluated by diffuse reflectance UV-vis spectroscopy revealed new absorption bands and a notable decrease of 1.83 eV in the bandgap energy from 3.68 eV (HKUST-1) to 1.85 eV (Cur@HKUST-1) due to guest molecule infiltration. Density functional theory (DFT) calculations supported the experimental findings, showing that guest HOMOs promoted the formation of a new valence band (VB), while the original VB remains lower in energy. Density-of-states analysis confirmed that the new VB originates from 2p orbitals belonging to the guest, while the conduction band remains predominantly Cu-based from the HKUST-1 framework. Photoelectrochemical characterization revealed that the guest-modified material exhibits an enhanced photocurrent response compared to HKUST-1. Cur@HKUST-1 displayed higher stability and stronger photocurrent density, attributed to its narrower bandgap and increased charge carrier density. These results demonstrate the potential of rational guest selection to engineer band structure and improve the light-harvesting performance of MOFs in solar-driven applications.