In situ preparation of visible-light-driven carbon quantum dots/NaBiO3 hybrid materials for the photoreduction of Cr(VI).

In this study, different carbon quantum dots (CQDs)/NaBiO3 hybrid materials were synthesized as photocatalysts to effectively utilize visible light for the photocatalytic degradation of contaminants effectively. These hybrid materials exhibit an enhanced photocatalytic reduction of hexavalent chromium (Cr(VI)) in the aqueous medium. Zero-dimensional nanoparticles of CQDs were embedded within the two-dimensional NaBiO3 nanosheets by the hydrothermal process. Compared with that of the pure NaBiO3 nanosheets, the photocatalytic performance of the hybrid catalysts was significantly high and 6 wt.% CQDs/NaBiO3 catalyst exhibited better photocatalytic performance. We performed the first-principles density functional theory calculations to study the interfacial properties of pure NaBiO3 nanosheets and hybrid photocatalysts, and confirmed the CQDs played an important role in the CQDs/NaBiO3 composites. The experimental results indicated that the enhanced reduction of Cr(VI) was probably due to the high loading of CQDs (electron acceptor) on NaBiO3, which made NaBiO3 nanomaterials to respond in visible light and significantly improved their electron-hole separation efficiency.

Sn Dopants with Synergistic Oxygen Vacancies Boost CO2 Electroreduction on CuO Nanosheets to CO at Low Overpotential.

Using the electrochemical CO2 reduction reaction (CO2RR) with Cu-based electrocatalysts to achieve carbon-neutral cycles remains a significant challenge because of its low selectivity and poor stability. Modulating the surface electron distribution by defects engineering or doping can effectively improve CO2RR performance. Herein, we synthesize the electrocatalyst of Vo-CuO(Sn) nanosheets containing oxygen vacancies and Sn dopants for application in CO2RR-to-CO. Density functional theory calculations confirm that the incorporation of oxygen vacancies and Sn atoms substantially reduces the energy barrier for *COOH and *CO intermediate formation, which results in the high efficiency, low overpotential, and superior stability of the CO2RR to CO conversion. This electrocatalyst possesses a high Faraday efficiency (FE) of 99.9% for CO at a low overpotential of 420 mV and a partial current density of up to 35.22 mA cm-2 at -1.03 V versus reversible hydrogen electrode (RHE). The FECO of Vo-CuO(Sn) could retain over 95% within a wide potential area from -0.48 to -0.93 V versus RHE. Moreover, we obtain long-term stability for more than 180 h with only a slight decay in its activity. Therefore, this work provides an effective route for designing environmentally friendly electrocatalysts to improve the selectivity and stability of the CO2RR to CO conversion.

Facile construction of 2D g-C3N4 supported nanoflower-like NaBiO3 with direct Z-scheme heterojunctions and insight into its photocatalytic degradation of tetracycline.

Photocatalytic oxidation using solar energy is a promising green technology to degrade antibiotic contaminants. Herein, a 2D g-C3N4 supported nanoflower-like NaBiO3 with direct Z-scheme heterojunction was synthesized via a facile hydrothermal approach, and the photocatalytic performance of g-C3N4/NaBiO3 was remarkable better than that of g-C3N4 and NaBiO3 for tetracycline degradation under visible light. Photoinduced electrons accumulated on the conduction band of g-C3N4 and holes gathered on the valence band of NaBiO3, which was more suitable for generating superoxide and hydroxyl radicals. Meanwhile, the built-in electric field between g-C3N4 and NaBiO3 was proved by their different work functions based on DFT calculations, which enhanced the charges separation. The formed radicals were determined by ESR, and their role in the degradation of tetracycline was examined by the active species trapping test. Moreover, the sites attacked by free radicals and degradation pathways for tetracycline were inferred by the results of Gaussian 09 program and HPLC-MS. The effects of water matrix and three other organic contaminants was further studied for actual use evaluation. Importantly, the prepared g-C3N4/NaBiO3 showed stable photodegradation activity for eight cycles. This work not only provides a promising photocatalyst, but also gets insight into the photocatalytic removal of tetracycline.

A Promising Alternative for Sustainable and Highly Efficient Solar-Driven Deuterium Evolution at Room Temperature by Photocatalytic D2 O Splitting.

Motivated by energy shortages and in view of current efforts to develop clean, renewable energy sources based on fusion, a solar-driven strategy has been developed for deuterium evolution. Deuterium is a critical resource for many aspects. However, the limited natural abundance of deuterium and the complexity of established technologies, such as quantum sieving (QS) for deuterium production under extreme conditions, pose challenges. The new method has the potential for robust and sustainable deuterium evolution, enabling deuterium production at a high rate of 9.745 mmol g-1 h-1 . The activity, thermodynamic, and kinetic characteristics are also investigated and compared between photocatalytic heavy water (D2 O) splitting and water (H2 O) splitting. This study opens a new avenue to discover promising photocatalytic deuterium generation systems for advanced solar energy utilization and deuterium enrichment.

In vitro studies on the antioxidant and protective effect of 2-substituted -8-hydroxyquinoline derivatives against H(2)O(2)-induced oxidative stress in BMSCs.

Novel 2-vinyl-8-hydroxyquinoline derivatives as potential antioxidants and regulators of H(2)O(2)-induced oxidative stress in rat bone marrow mesenchymal stem cells (MSCs) are first reported. The antiradical properties and the reducing power of these compounds were assessed using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and auto-oxidation of pyrogallol method, respectively. The activity against lipid peroxidation was determined using ammonium thiocyanate method. The results revealed that introduction of electron-donating groups at 2nd position decreased the antioxidant activities of 8-hydroxyquinoline derivatives. In addition, compound 4, the structure of which is similar to melatonin, exhibited superior antioxidant activities in scavenging DPPH free radical, O(2) free radical, and anti-LPO activities. Except for compounds 7, 12, and 15, the other compounds exhibited a stimulatory effect on MSCs growth. Using hydrogen peroxide (H(2)O(2)), we also investigated the protective efficacy of 2-vinyl-8-hydroxyquinoline derivatives against oxidative stress-induced cell death of MSCs. Cell viability assayed by MTT method indicated that exposure of MSCs cultures to hydrogen peroxide resulted in a concentration-dependent decrease in cell viability, and compounds 4 and 5 at given concentration (2.62 x 10(-3) m) could protect MSCs against H(2)O(2)-induced oxidative stress in bone mesenchymal stem cell (BMSCs).