This work developed a strategy to enhance the photocatalytic activity of ZnO by doping it with silver nanoparticles (Ag) to improve the light adsorption and separation of charge carriers, which further increases the conversion of CO₂. The loading of Ag over ZnO (Ag-ZnO) was confirmed by characterization methods (SEM, XRD, and XPS), and the photocatalytic activities of Ag-ZnO were significantly enhanced. As the result, the production rates of CO and CH₄ by doped Ag-ZnO were 9.8 and 2.4 µmol g⁻¹ h⁻¹, respectively. The ZnO that had the production rate of CO was 3.2 µmol g⁻¹ h⁻¹ and it is relatively low for the production of CH₄ at around 0.56 µmol g⁻¹ h⁻¹. The doping of Ag over ZnO displayed a high conversion rate for both CO and CH₄, which were 3 and 4.2 times higher than that of ZnO. The doped Ag-ZnO photocatalyst also had high stability up to 10 cycles with less than 11% loss in the production of CO and CH₄. The improvement of photocatalytic activities of Ag-ZnO was due to the Ag doping, which enhanced the light adsorption (400–500 nm) and narrowed band gap energy (2.5 eV), preventing the charge carrier separation. This work brings an efficient photocatalyst for CO₂ conversion in order to reduce carbon dioxide concentration as well as greenhouse gas emissions.

Endophytic fungi are recognized for their many potential applications in agriculture, such as supporting cropland expansion and increasing the yield and resistance of plants by creating antibiotics that inhibit the growth of pathogenic microorganisms. In addition, they can produce enzymes that break down hard-to-solubilize substances within soil, dissolve phosphates, fix nitrogen, reduce metals, and produce hormones that promote plant growth (auxin, cytokinin, and gibberellins) to keep crops healthy. In this report, three strains of endophytic fungi, namely, N1, N2, and N3, were isolated from the roots of Stevia rebaudiana (Bert.) Hemsl., Polyscias fruticosa, and Angelica dahurica in some localities in Vietnam. Through a screening process, it was found that they can produce high levels of indole acetic acid (IAA), resolve phosphates, and resist disease, and they were selected to as an alternative to chemical fertilizers to make probiotics in order to increase medicinal plant yields. The results show that the three strains of fungi have the ability to degrade phosphate to 341.90, 1498.46, and 390.79 ppm; the content of IAA produced in the culture medium reached 49.00, 52.35, and 33.34 ppm. Based on some morphological characteristics and an internal transcribed spacer gene sequence analysis of the fungal strains, N1, N2, and N3 were named Penicillium simplicissimum CN7, Talaromyces flavus BC1, and Trichoderma konilangbra DL3, respectively, which have the ability to inhibit the growth of pathogenic fungal strains, such as fungus C. gloeosporioides (CD1), fungus F. oxysporum, fungus L. theobromae N13, and N. dimidiatum. They grow significantly over a period of 5 to 6 days.