Tuning the morphology to enhance the catalytic activity of α-Ag2WO4 through V-doping.

Here, we present the synthesis of a highly efficient V-doped α-Ag2WO4 catalyst for the oxidation of sulfides to sulfones, exhibiting a high degree of tolerance towards various sensitive functional groups. Remarkably, the catalysts with 0.01% V-doping content exhibited outstanding selectivity towards the oxidation process. Scavenger experiments indicated the direct involvement of electron-hole (e-/h+) pairs, hydroxyl radical (˙OH), and singlet oxygen (1O2) in the catalytic mechanism. Based on the experimental and theoretical results, the higher activity of the V-doped α-Ag2WO4 samples was associated with the preferential formation of the (100) surface in the catalyst morphology.

Single-walled silicon nanotube as an exceptional candidate to eliminate SARS-CoV-2: a theoretical study.

In this work, computational chemistry methods were used to study a silicon nanotube (Si192H16) as possible virucidal activity against SARS-CoV-2. This virus is responsible for the COVID-19 disease. DFT calculations showed that the structural parameters of the Si192H16 nanotube are in agreement with the theoretical/experimental parameters reported in the literature. The low energy gap value (0.29 eV) shows that this nanotube is a semiconductor and exhibits high reactivity. For nanomaterials to be used as virucides, they need to have high reactivity and high inhibition constant values. Therefore, the adsorption of 3O2 and H2O on the surface of Si192H16 (Si192H16@O2-H2O) was performed. In this process, the formation and activation energies were -51.63 and 16.62 kcal/mol, respectively. Molecular docking calculations showed that the Si192H16 and Si192H16@O2H-OH nanotubes bind favorably on the receptor-binding domain of the SARS-CoV-2 spike protein with binding energy of -11.83 (Ki = 2.13 nM) and -11.13 (Ki = 6.99 nM) kcal/mol, respectively. Overall, the results obtained herein indicate that the Si192H16 nanotube is a potential candidate to be used against COVID-19 from reactivity process and/or steric impediment in the S-protein.Communicated by Ramaswamy H. Sarma.

SiO2-Ag Composite as a Highly Virucidal Material: A Roadmap that Rapidly Eliminates SARS-CoV-2.

COVID-19, as the cause of a global pandemic, has resulted in lockdowns all over the world since early 2020. Both theoretical and experimental efforts are being made to find an effective treatment to suppress the virus, constituting the forefront of current global safety concerns and a significant burden on global economies. The development of innovative materials able to prevent the transmission, spread, and entry of COVID-19 pathogens into the human body is currently in the spotlight. The synthesis of these materials is, therefore, gaining momentum, as methods providing nontoxic and environmentally friendly procedures are in high demand. Here, a highly virucidal material constructed from SiO2-Ag composite immobilized in a polymeric matrix (ethyl vinyl acetate) is presented. The experimental results indicated that the as-fabricated samples exhibited high antibacterial activity towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as well as towards SARS-CoV-2. Based on the present results and radical scavenger experiments, we propose a possible mechanism to explain the enhancement of the biocidal activity. In the presence of O2 and H2O, the plasmon-assisted surface mechanism is the major reaction channel generating reactive oxygen species (ROS). We believe that the present strategy based on the plasmonic effect would be a significant contribution to the design and preparation of efficient biocidal materials. This fundamental research is a precedent for the design and application of adequate technology to the next-generation of antiviral surfaces to combat SARS-CoV-2.