Photocatalytic Activity of Bi₂O₃ Enhanced by the Addition of Ce³⁺/Ce⁴⁺ Synthesized by Ethylene Glycol‐assisted Solvothermal Method

Abstract

The photocatalysts Bi 2 O 3 :Ce 3 + /Ce 4 + (cerium content 0.2, 0.5, 0.8, and 1.1 wt. %) were prepared via one-pot ethylene glycolassisted solvothermal method. The prepared x Ce-Bi 2 O 3 (x = 0.5, 0.8, 1.1) samples present δ-Bi 2 O 3 phase with space group of Fm-3 m at room temperature, which indicates that the hightemperature cubic phase could be stabilized via Ce doping in Bi 2 O 3 lattices. Moreover, the addition of Ce 3 + /Ce 4 + could change the amount of oxygen vacancies (OVs) and adsorbed oxygen on the surface of photocatalysts. The existence of oxygen vacancies and adsorbed oxygen facilitated the generation of superoxide radicals () and hydroxide radicals (), which were the dominant reactive oxygen species for phenol degradation. The photocatalyst containing 0.8 wt. % cerium presented the highest photoactivity than the other synthesized samples. A photodegradation mechanism is proposed based on scavenger and electron spin resonance studies.[a] T.

Multifunctional bismuth oxide (Bi2O3) particles: Evidence for selective melanoma therapy

“…The introduction of impurities within the crystal lattice of Bi 2 O 3 through doping could aid enhance the UVA absorption properties of the base material, conferring the sample broad UV protection properties. However, this could in turn lead to an improvement of the photocatalytic activity of Bi 2 O 3 , as it has been previously reported, 21 and the consequent promotion of toxic radical generation. The optical band gap ( E g ) values of ZnO and Bi 2 O 3 were determined from their respective Tauc plots (Figure 3B).…”

“…Peak deconvolution of the O 1 s region yielded three peaks located at approximately 529, 531, and 533 eV (Figure 2B). According to the previous findings, the peaks could be assigned to lattice oxygen (Bi–O–Bi), oxygen vacancies or surface adsorbed carbonate species (CO 3 2− ), and surface adsorbed hydrated species (H–O–H), respectively 21,32 . However, the presence of oxygen vacancies in Bi 2 O 3 has been reported to result in the broadening of both Bi 3+ peaks 31 .…”

“…), and surface adsorbed hydrated species (H-O-H), respectively. 21,32 However, the presence of oxygen vacancies in peaks. 31 Therefore, the absence of this phenomenon in Figure 2A suggests that the peak at approximately 531 eV in the O 1 s XPS spectrum is ascribed to carbonate species bound to the surface of Bi 2 O 3 .…”

“…It is demonstrated that Bi 2 O 3 shows cell death specificity for A375 melanoma cells, compared with human skin keratinocyte (HaCaT) and fibroblast (CCD‐1090Sk) cells when tested under similar conditions. Additionally, Bi 2 O 3 shows promise as a candidate material for ultraviolet (UV) radiation protection due to its UV absorption ability owing to its band gap of approximately 2.9 eV, somewhat low photoactivity and low manufacturing costs 20,21 . As such, due to the developing nature of melanoma being ascribed to the accumulation of UV radiation‐induced mutations 22 in melanocytes in the basal layer of the epidermis, 23 Bi 2 O 3 could be employed as a primary preventive agent either by blocking the incident UV radiation as a physical UV blocker or as a nanomaterial functioning by UV absorption in a clear sunscreen.…”

“…Additionally, Bi 2 O 3 shows promise as a candidate material for ultraviolet (UV) radiation protection due to its UV absorption ability owing to its band gap of approximately 2.9 eV, somewhat low photoactivity and low manufacturing costs. 20,21 As such, due to the developing nature of melanoma being ascribed to the accumulation of UV radiation-induced mutations 22 in melanocytes in the basal layer of the epidermis, 23 Bi 2 O 3 could be employed as a primary preventive agent either by blocking the incident UV radiation as a physical UV blocker or as a nanomaterial functioning by UV absorption in a clear sunscreen. Moreover, Bi 2 O 3 particles already find use in topical creams, further highlighting the potential inclusion of Bi 2 O 3 in sunscreen products for UV protection.…”