Unraveling the relationship between exposed surfaces and the photocatalytic activity of Ag3PO4: an in-depth theoretical investigation

Mechanism of Action and Efficiency of Ag3PO4-Based Photocatalysts for the Control of Hazardous Gram-Positive Pathogens

Silver phosphate and its composites have been attracting extensive interest as photocatalysts potentially effective against pathogenic microorganisms. The purpose of the present study was to investigate the mechanism of bactericidal action on cells of opportunistic pathogens. The Ag3PO4/P25 (AGP/P25) and Ag3PO4/HA (HA/AGP) powders were prepared via a co-precipitation method. Thereafter, their antimicrobial properties against Enterococcus faecalis, Staphylococcus epidermidis, and Staphylococcus aureus (clinical and reference strains) were analyzed in the dark and after exposure to visible light (VIS). The mechanism leading to cell death was investigated by the leakage of metabolites and potassium ions, oxidative stress, and ROS production. Morphological changes of the bacterial cells were visualized by transmission electron microscopy (TEM) and scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (SEM EDS) analysis. It has been shown that Ag3PO4-based composites are highly effective agents that can eradicate 100% of bacterial populations during the 60 min photocatalytic inactivation. Their action is mainly due to the production of hydroxyl radicals and photogenerated holes which lead to oxidative stress in cells. The strong affinity to the bacterial cell wall, as well as the well-known biocidal properties of silver itself, increase undoubtedly the antimicrobial potential of the Ag3PO4-based composites.

Unraveling the MnMoO4 polymorphism: a comprehensive DFT investigation of α, β, and ω phases

The MnMoO₄ is an environmentally friendly semiconductor material widely employed in technological devices. This material can be obtained on three different polymorphs, and although such phases were reported decades ago, some obscurity over their structure and properties is still perceived. Thus, this work provides a comprehensive DFT investigation of the α, β, and ω phases of MnMoO_4, analyzing their crystalline structure, stability, and electronic and magnetic properties. The results show that all phases of MnMoO₄ are stable at room conditions connected by pressure application or long-time high-temperature treatment. The MnMoO₄ phases are G-type antiferromagnetic with semiconductor bandgap and have enormous potential to develop magnetic, optical, and electronic devices and photocatalytic-based processes. The results also evidence potential antiviral and antibacterial activities of the three MnMoO₄ polymorphs.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10853-022-07277-7.

Sonochemical synthesis of ZnCo2O4/Ag3PO4 heterojunction photocatalysts for the degradation of organic pollutants and pathogens: a combined experimental and computational study

ZnCo2O4/Ag3PO4 heterostructure nanoparticles were prepared by a facile ultrasonic method and characterized by various techniques. The photocatalytic activity of ZnCo2O4/Ag3PO4 nanoparticles was investigated for the degradation of organic pollutants (methyl...

Bioactive Ag3PO4/Polypropylene Composites for Inactivation of SARS-CoV-2 and Other Important Public Health Pathogens

The current unprecedented coronavirus pandemic (COVID-19) is increasingly demanding advanced materials and new technologies to protect us and inactivate SARS-CoV-2. In this research work, we report the manufacture of Ag3PO4 (AP)/polypropylene (PP) composites using a simple method and also reveal their long-term anti-SARS-CoV-2 activity. This composite shows superior antibacterial (against Staphylococcus aureus and Escherichia coli) and antifungal activity (against Candida albicans), thus having potential for a variety of technological applications. The as-manufactured materials were characterized by XRD, Raman spectroscopy, FTIR spectroscopy, AFM, UV-vis spectroscopy, rheology, SEM, and contact angle to confirm their structural integrity. Based on the results of first-principles calculations at the density functional level, a plausible reaction mechanism for the initial events associated with the generation of both hydroxyl radical •OH and superoxide radical anion •O2- in the most reactive (110) surface of AP was proposed. AP/PP composites proved to be an attractive avenue to provide human beings with a broad spectrum of biocide activity.