Development of gelatin/agarose active coatings functionalized with Ocimum gratissimum L. essential oil for enhancing storability of 'Booth 7' avocado.

Novel active coating from gelatin/agarose (GA) functionalized with Ocimum gratissimum L. essential oil (OGO) had been developed as a medium to evaluate their properties before being applied for avocado preservation. The resultant coating films showed enhanced mechanical, water-barrier, bactericidal, antioxidant, and UV-shielding properties by adding OGO. The best tensile strength (2.91 MPa) and flexibility (45.82 %) was found in the GA film containing 5 % (w/w) of OGO (GA-OGO-5). Furthermore, this coating formulation presented moderate antibacterial activities against Listeria, Pseudomonas, Salmonella, and Escherichia. The GA-OGO-5 coating film also divulged the highest hydrophobicity and adequate antioxidant function (30.75 µg/mL) and thus, was chosen to coat on 'Booth 7' avocados by dipping method. The GA-OGO-5 coating layers were to be efficient to decline the respiration rate of avocado during 6-day storage at 25 °C and 64 %RH. Peel color, weight loss (5.22 %), total soluble solids (8.14 %), and solution pH (6.79) at the end of storage also indicated that the GA-OGO-5 coating presented the best effectiveness for enhancing the storability of avocado as compared to uncoated and GA-treated fruit. Therefore, the GA-OGO coating has been considered as an alternative post-harvest technique to enhance the avocado storability and could be further commercialized for industry application.

Photocatalytic degradation of methyl orange dye by Ti3C2-TiO2 heterojunction under solar light.

Photocatalytic activity is a feasible solution to tackle environmental pollution caused by industrial pollutants. In this research, Ti3C2-TiO2 composite with a unique structure was fabricated successfully via a hydrothermal method. Especially, the in-situ transformation of TiO2 from Ti3C2 MXene creates an intimate heterostructure, which leads to prolonging separation and migration of charged carriers. Thus, this Ti3C2-TiO2 composite enhances effectively methyl orange (MO) degradation efficiency (around 99%) after 40 light-exposed minutes. Besides, the optimal concentration of MO solution was estimated at 40 mg/L and Ti3C2-TiO2 photocatalyst also exhibited good stability after five runs. Moreover, the radical trapping test and the MO photodegradation mechanism over Ti3C2-TiO2 system were also demonstrated. This research illustrates the potential of MXenes as effective co-catalysts for photocatalysis and extends the applications of two-dimensional materials.

Unraveling the effect of Al doping on CO adsorption at ZnO(101̄0).

Understanding the effect of Al doping on CO adsorption at ZnO(101̄0) is crucial for designing a high-performance CO gas sensor. In this work, we investigated the adsorption properties of CO on pristine and Al-doped ZnO(101̄0) by performing DFT+U calculations. It is found that the doping of Al on ZnO(101̄0) induces the semiconductor-to-metal transition and thus enhances the conductance of the substrate. Compared to the pristine ZnO(101̄0), the adsorption energy of CO on the Al-doped surfaces is significantly enhanced since Al doping has the effect of strengthening the adsorption bond. The bonding analysis reveals that CO adsorbs on pristine ZnO(101̄0) via the sole σ-dative donation between the CO HOMO 5σ and the empty states of the Zn cation while π-back donation from filled states of Zn or Al cations to the CO 2π* LUMO is facilitated on the Al-doped surfaces. The π-back donation also results in the red-shift of the CO stretching frequency on the Al-doped surfaces, contrasting to the blue-shift on the pristine surface. The simulated results demonstrate that the doping of Al to a three-fold coordinated site on ZnO(101̄0) is highly beneficial for boosting the performance of the CO gas sensor. Our theoretical investigation provides fundamental insights into the effect of Al doping on the sensing mechanism for CO at the ZnO(101̄0) surface.