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The potential of photocatalytic CO2 conversion is significant for the production of fuels and chemicals, while simultaneously mitigating CO2 emissions and addressing environmental concerns. Despite the current drawbacks of single metal-based photocatalysts, such as lower performance, uncontrollable selectivity, and instability, this study focuses on the synthesis of Ag3VO4 nanorods using the sol–gel method. The goal is to create a highly effective catalyst for visible light-responsive CO2 conversion. The successful synthesis of Ag3VO4 nanorods with a nanorod structure, functional under visible light, resulted in the highest yields of CH4 and dimethyl ether (DME) at 271 and 69 µmole/g-cat, respectively. The optimized Ag3VO4 nanorods demonstrated performance improvements, with CH4 and DME production 6.4 times and 4.5 times higher than when using V2O5 samples. This suggests that Ag3VO4 nanorods facilitate electron transfer to CO2, offer short pathways for electron transfer, and create empty spaces within the nanorods as electron reservoirs, enhancing the photoactivity. The prolonged stability of Ag3VO4 in the CO2 conversion system confirms that the nanorod structure provides controllable selectivity and stability. Therefore, the fabrication of nanorod structures holds promise in advancing high-performance photocatalysts in the field of photocatalytic CO2 conversion to solar fuels. [ABSTRACT FROM AUTHOR]

Groundwater contamination with per- and polyfluoroalkyl compounds (PFASs) has become a growing worldwide environmental issue. The current review comprehensively evaluates the global perspective of PFAS pollution in groundwater. Data from 224 recent research articles covering various land use and source types were reviewed, including industrial facilities, landfills, biosolids applications, and firefighting training sites. The bibliographic analysis shows an exponential increase in publications on PFAS pollution in groundwater in the last five years, with more than 50% coming from the USA, followed by Australia, Canada, China, and Sweden. The recent groundwater PFAS pollution research provides insight into the analytical techniques, absorbing materials, treatment strategies, field tests, and enhanced natural attenuation. Nevertheless, the current review identified significant research gaps in the areas of precursor characterization, subsurface behavior, model validation with field data, and long-term and sustainable solutions. Moreover, a global cross-disciplinary approach is required to reduce and regulate PFASs' risks to humans and the ecological system. This review presents a case study of PFASs in Saudi Arabian groundwater, revealing elevated levels of PFOA and PFOS and highlighting the need for region-specific studies and remediation strategies. The review results will guide global efforts to protect drinking water supplies from life-threatening contaminants. [ABSTRACT FROM AUTHOR]

The melt-quenching method was used to synthesize the samples of the [(75 − x)B2O3–10TeO2–13SrO–2.0ZnO–xPbO (x = 0.0, 5.0, 10, 15, 25, and 40 mol%)]. The peaks found in the XRD patterns were associated with the crystalline phase, Zn2Te3O8, present in these prepared samples. Substituting B2O3 with PbO resulted in a steady density increase from 2.89 to 4.75 g/cm3. The molar volume (Vm) increased from 30.23 to 31.95 cm3/mol as the concentration of PbO went up from 0 to 40 mol%. The Raman analysis confirmed that the increase in PbO content in the compositions led to a conversion from TeO4 to TeO3 and the change of bridging oxygens to non-bridging oxygens. The optical band gap energy, Urbach energy, and other optical properties were analyzed to determine the optical transmission data. As more PbO was added, the optical band gap energy decreased from 3.140 to 2.930 eV, and the Urbach energy rose from 0.337 to 0.377 eV. Under 300 nm excitation, the photoluminescence spectra showed emission bands linked to electronic transitions of Pb2+. [ABSTRACT FROM AUTHOR]

Glass samples comprising Bi2O3, B2O3, TeO2, MgO, and PbO were fabricated using melt quenching. Substituting B2O3 with Bi2O3 resulted in a steady density increase from 2.88 to 7.16 g/cm3 due to the difference in atomic weight between the heavier Bi (208.98 g/mol) and lighter B (10.811 g/mol). As the Bi2O3 concentration rose from 0 to 60 mol%, the molar volume (Vm) gradually increased from 31.02 to 45.69 cm3/mol, owing to the discrepancy in the radii of the Bi3+ and B3+ ions, measuring 0.96 and 0.84 Å, respectively. Increasing the non-bridging oxygens (NBOs) led to a corresponding rise in the molar volume. Incorporating varying concentrations of Bi2O3, ranging from 0 mol% (BMTPBi0) to 60 mol% (BMTPBi60), induced alterations in several physical parameters, consequently affecting the structural characteristics of the glass. Raman analysis confirmed that an increase in Bi2O3 content within the glass composition led to the conversion of TeO4 to TeO3, resulting in the transformation of bridging oxygens into NBOs. As the Bi2O3 content increased, there was a 3.080–2.090 eV decrease in the optical band gap energy as a result of the rise in NBOs (and consequently, an increase in disorder), leading to a rise in Urbach energy from 0.390 to 0.740 eV. The optimal sample was determined as BTMPBi30 due to its balanced properties and potential advantages. The BTMPBi30 as modifier with heavy metal has high transmittance. The band gap energy of BTMPBi30 (2.920 eV) is reasonable and falls within the range suitable for many optical applications. The Urbach energy increases with Bi2O3 content, and for BTMPBi30 (ΔE = 0.480 eV), it is within an acceptable range, indicating a certain level of disorder. Under 300 nm excitation, the photoluminescence spectra indicate distinct emission bands dependent on the species Bi3+ and Pb2+, making BTMPBi30 a potential candidate for applications requiring photoluminescent properties. [ABSTRACT FROM AUTHOR]

This work explores the thermoluminescence (TL) and photoluminescence (PL) properties of Ag/Y co‐doped zinc oxide (ZnO) nanophosphor. The proposed dosimeter was prepared by the coprecipitation method and sintered at temperatures from 400°C to 1000°C in an air atmosphere. Raman spectroscopy was studied to investigate the structural features of this composition. The new proposed dosimeter revealed two peaks at 150°C and 175°C with a small shoulder at high temperature (225°C). The PL spectrum showed strong green emissions between 500 to 550 nm. The Raman spectrum showed many bands related to the interaction between ZnO, silver (Ag), and yttrium oxide (Y2O3). The rising sintering temperature enhanced the TL glow curve intensity. The Ag/Y co‐doped ZnO nanophosphor showed an excellent linearity index within a dose from 1 to 4 Gy. The minimum detectable dose (MDD) of the Ag/Y co‐doped ZnO nanopowder (pellets) equaled 0.518 mGy. The main TL properties were achieved in this work as follows: thermal fading (37% after 45 days at 1 and 4 Gy), optical fading (53% after 1 h and 68% after 6 h by exposure to sunlight), effective atomic number (27.6), and energy response (flat behavior from 0.1 to 1.3 MeV). Finally, the proposed material shows promising results nominated to be used for radiation measurements. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of CO2 with CH4 through the dry reforming of methane (DRM) is an attractive approach to recycling greenhouse gases into valuable chemicals and fuels; however, this process is quite challenging. Although there is growing interest in designing efficient photocatalysts, they are less stable, and have lower photoactivity when employed for DRM reactions. Herein, we developed a noble metal-free hierarchical graphitic carbon nitride (HC3N4) loaded with cobalt (Co) for highly efficient and stable photocatalytic dry reforming of methane to produce synthesis gases (CO and H2). The performance of the newly designed Co/HC3N4 composite was tested for different reforming systems such as the dry reforming of methane, bi-reforming of methane (BRM) and reforming of CO2 with methanol–water. The performance of HC3N4 was much higher compared to bulk g-C3N4, whereas Co/HC3N4 was found to be promising for higher charge carrier separation and visible light absorption. The yield of CO and H2 with HC3N4 was 1.85- and 1.81-fold higher than when using g-C3N4 due to higher charge carrier separation. The optimized 2% Co/HC3N4 produces CO and H2 at an evolution rate of 555 and 41.2 µmol g−1 h−1, which was 18.28- and 1.74-fold more than using HC3N4 during photocatalytic dry reforming of methane (DRM), with a CH4/CO2 feed ratio of 1.0. This significantly enhanced photocatalytic CO and H2 evolution during DRM was due to efficient charge carrier separation in the presence of Co. The CH4/CO2 feed ratio was further investigated, and a 2:1 ratio was best for CO production. In contrast, the highest H2 was produced with a 1:1 feed ratio due to the competitive adsorption of the reactants over the catalyst surface. The performance of the composite was further investigated for bi-reforming methane and methanol. Using photocatalytic CO2 reduction with CH4/H2O, the production of CO and H2 was reduced, whereas significantly higher CO and H2 evolved using the BRM process involving methanol. Using methanol with CO2 and H2O, 10.77- and 1.39-fold more H2 and CO efficiency was achieved than when using dry reforming of methane. The composite was also very stable for continuous synthesis gas production during DRM in consecutive cycles. Thus, a co-assisted g-C3N4 nanotexture is promising for promoting photocatalytic activity and can be further explored in other solar energy applications. [ABSTRACT FROM AUTHOR]

Hierarchical structures have recently attracted significant interest due to their exceptional performance in energy storage and catalytic applications. In this study, novel hierarchical Fe2TiO5 nanosheets, fabricated by one-step solvothermal process, for boosted photocatalytic conversion of CO2 with water to fuels, were investigated. The characteristics and properties of these photocatalysts were analyzed using various techniques including XRD, FESEM, TEM, XPS, UV–vis, and PL spectroscopy. The hierarchical Fe2TiO5 nanosheets demonstrated significant performance, yielding 149.5 µmole/g-cat of CH3OH and 61.6 µmole/g-cat of dimethyl ether (DME), respectively. Compared to TiO2 samples, the optimized 2D hierarchical nanosheets of Fe2TiO5 displayed 3.8-fold and 4.1-fold higher efficiency in CH3OH and DME production, highlighting the advantages of their structure. The 2D hierarchical nanosheets of Fe2TiO5 facilitate electron transfer to CO2 due to their unique structure, providing efficient electron pathways and electron storage sites within the nanosheets, thereby enhancing photoactivity. Moreover, the extended stability of Fe2TiO5 in CO2 conversion further confirms the controllable selectivity and stability offered by the 2D hierarchical nanosheets structure. This study suggests that the fabrication of hierarchical structures holds promise for advancing high-performance photocatalysts for solar fuel production through CO2 conversion. [ABSTRACT FROM AUTHOR]

This work explores the thermoluminescence (TL) and photoluminescence (PL) properties of Ag/Y co-doped zinc oxide (ZnO) nanophosphor. The proposed dosimeter was prepared by the coprecipitation method and sintered at temperatures from 400°C to 1000°C in an air atmosphere. Raman spectroscopy was studied to investigate the structural features of this composition. The new proposed dosimeter revealed two peaks at 150°C and 175°C with a small shoulder at high temperature (225°C). The PL spectrum showed strong green emissions between 500 to 550 nm. The Raman spectrum showed many bands related to the interaction between ZnO, silver (Ag), and yttrium oxide (Y 2 O 3 ). The rising sintering temperature enhanced the TL glow curve intensity. The Ag/Y co-doped ZnO nanophosphor showed an excellent linearity index within a dose from 1 to 4 Gy. The minimum detectable dose (MDD) of the Ag/Y co-doped ZnO nanopowder (pellets) equaled 0.518 mGy. The main TL properties were achieved in this work as follows: thermal fading (37% after 45 days at 1 and 4 Gy), optical fading (53% after 1 h and 68% after 6 h by exposure to sunlight), effective atomic number (27.6), and energy response (flat behavior from 0.1 to 1.3 MeV). Finally, the proposed material shows promising results nominated to be used for radiation measurements., (© 2024 John Wiley & Sons Ltd.)