Photocatalytic degradation of methyl orange by Ca doped β-In2S3 with varying Ca concentration

Visible Light Motivated the Photocatalytic Degradation of P-Nitrophenol by Ca2+-Doped AgInS2

4-Nitrophenol (4-NP) is considered a priority organic pollutant with high toxicity. Many authors have been committed to developing efficient, green, and environmentally friendly technological processes to treat wastewater containing 4-NP. Here, we investigated how the addition of Ca2+ affects the catalytic degradation of 4-NP with AgInS2 when exposed to light. We synthesized AgInS2 (AIS) and Ca2+-doped AgInS2 (Ca-AIS) with varying amounts of Ca2+ using a low-temperature liquid phase method. The SEM, XRD, XPS, HRTEM, BET, PL, and UV-Vis DRS characteristics were employed to analyze the structure, morphology, and optical properties of the materials. The effects of different amounts of Ca2+ on the photocatalytic degradation of 4-NP were investigated. Under visible light illumination for a duration of 120 min, a degradation rate of 63.2% for 4-Nitrophenol (4-NP) was achieved. The results showed that doping with an appropriate amount of Ca2+ could improve the visible light catalytic activity of AIS. This work provides an idea for finding suitable cheap alkaline earth metal doping agents to replace precious metals for the improvement of photocatalytic activities.

The Solid-State Synthesis of BiOIO3 Nanoplates with Boosted Photocatalytic Degradation Ability for Organic Contaminants

BiOIO₃ exhibits excellent oxidation capacity in the photocatalytic degradation of contaminants thanks to its unique polarized electric and internal electrostatic field. However, the synthetic method of BiOIO₃ nanomaterials is mainly focused on hydrothermal technology, owing to its high energy consumption and time-consuming nature. In this work, a BiOIO₃ nanosheet was prepared by a simple solid-state chemical reaction, which was identified by XRD, EDS, XPS, and HRTEM. Benefiting from the strong oxidation ability of the valence band maximum, the distinctive layer structure, and the promoted generation of ·O₂^-, the BiOIO₃ nanosheet exhibits excellent photo-degradation activity for methyl orange (MO) and its apparent rate constant is 0.2179 min^-1, which is about 3.02, 8.60, and 10.26 times higher than that of P25, BiOCl, and Bi₂O₂CO₃, respectively. Interestingly, the BiOIO₃ nanosheet also has good photocatalytic degradation performance for phenolic compounds; in particular, the degradation rate of BPA can reach 96.5% after 16 min, mainly due to hydroxylation reaction.

One-pot solvothermal synthesis of flower-like Fe-doped In2S3/Fe3S4 S-scheme hetero-microspheres with enhanced interfacial electric field and boosted visible-light-driven CO2 reduction

S-scheme heterojunctions hold great potential for CO2 photoreduction into solar fuels, but their activities are severely limited by the low efficiency of interfacial charge transfer. In this work, a facile one-pot solvothermal reaction has been developed to dope Fe into flower-like In2S3/Fe3S4 hetero-microspheres (Fe-In2S3/Fe3S4 HMSs), which are demonstrated as an efficient S-scheme photocatalyst for visible-light-driven CO2 photoreduction. The doping of Fe not only reduces the bandgap of In2S3 and thus extends the optical response to the visible-light region, but also increases the densities of donors and sulfur vacancies, which leads to an elevated Fermi level (Ef). The difference of Ef between In2S3 and Fe3S4 is enlarged and their band bending at the interface is therefore enhanced, which results in promoted carriers transfer in the S-scheme pathway due to the reinforced interfacial electric field. Moreover, Fe-doped In2S3 reduces the formation energy of the *CO intermediate, which thermodynamically favors the CO evolution at the surface. As a result, the Fe-In2S3/Fe3S4 HMSs exhibit a significantly boosted CO2 photoreduction activity in comparison with bare In2S3 and Fe-In2S3 samples. This work demonstrates the great potential of heteroatom-engineered S-scheme photocatalysts for CO2 photoreduction.

Dependence of Photocatalytic Activity on the Morphology of Strontium Titanates

Strontium titanates were prepared with different morphologies by varying the ratio of solvents used during the synthesis. The effects of morphology and solvent (ethylene glycol to water) ratio were investigated both on the structure and photocatalytic activity of the samples. Structural properties were determined by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and nitrogen adsorption measurements. The photocatalytic activity of the samples was evaluated by the photocatalytic oxidation of phenol and by the photocatalytic reduction of carbon dioxide. The ratio of solvents notably influenced the morphology, strontium carbonate content, primary crystallite size, and specific surface area of the samples. Samples prepared at low ethylene glycol to water ratios were spherical, while the ones prepared at high ethylene glycol to water ratios could be characterized predominantly by lamellar morphology. The former samples were found to have the highest efficiency for phenol degradation, while the sample with the most well-defined lamellar morphology proved to be the best for CO2 reduction.

High concentration of methyl orange elimination by targeted construction of an α-Bi2O3/Ph–CC–Cu Z-scheme

We anchored Ph–CC–Cu onto the surface of α-Bi2O3 nanoparticles to directionally construct Z-scheme heterojunctions, which are significantly efficient for the elimination of methyl orange with high concentration (98 mg L−1) in waste water.