Efficient tandem electroreduction of nitrate into ammonia through coupling Cu single atoms with adjacent Co3O4.

The nitrate (NO3-) electroreduction into ammonia (NH3) represents a promising approach for sustainable NH3 synthesis. However, the variation of adsorption configurations renders great difficulties in the simultaneous optimization of binding energy for the intermediates. Though the extensively reported Cu-based electrocatalysts benefit NO3- adsorption, one of the key issues lies in the accumulation of nitrite (NO2-) due to its weak adsorption, resulting in the rapid deactivation of catalysts and sluggish kinetics of subsequent hydrogenation steps. Here we report a tandem electrocatalyst by combining Cu single atoms catalysts with adjacent Co3O4 nanosheets to boost the electroreduction of NO3- to NH3. The obtained tandem catalyst exhibits a yield rate for NH3 of 114.0 mg NH 3 h-1 cm-2, which exceeds the previous values for the reported Cu-based catalysts. Mechanism investigations unveil that the combination of Co3O4 regulates the adsorption configuration of NO2- and strengthens the binding with NO2-, thus accelerating the electroreduction of NO3- to NH3.

Methanol as an anti-solvent to improve the low open-circuit voltage of CsPbBr3 perovskite solar cells prepared with water.

CsPbBr3 has received more and more attention in the field of optoelectronic devices due to its excellent stability. To address the cost and environmental concerns associated with the use of toxic methanol, water has been explored as a substitute solvent for CsBr in the preparation of CsPbBr3 perovskite solar cells (PSCs). In this study, we utilized methanol as an anti-solvent of the CsBr/H2O solution to regulate the detrimental effects of water on the CsPbBr3 film and control the crystallization process. From results of the experiment, it was found that methanol anti-solvent treatment greatly improved the crystallization of the CsPbBr3 film, increased the grain size, and reduced the defect density. After the introduction of methanol anti-solvent treatment, the power conversion efficiency (PCE) increased from 6.09% to 7.91%, while the open-circuit voltage (Voc) increased from 1.18 V to 1.39 V. Furthermore, we incorporated 2-hydroxyethylurea into the CsPbBr3 PSCs to improve the wettability of PbBr2 towards the CsBr/H2O solution and ensure the formation of pure-phase CsPbBr3 films. The introduction of 2-hydroxyethylurea resulted in an additional increase in Voc from 1.19 V to 1.42 V. The PCE further improved from 6.56% to 8.62% after methanol anti-solvent treatment. These results demonstrate that methanol treatment effectively addresses the low Voc issue observed in CsPbBr3 PSCs prepared with water as a solvent. Importantly, this approach significantly reduces the reliance on methanol compared to conventional fabrication methods for CsPbBr3 PSCs. Overall, this work presents a promising pathway for achieving high Voc and efficiency in CsPbBr3 PSCs by utilizing water as a solvent.

Improvement of the Stability and Optical Properties of CsPbBr3 QDs.

All-inorganic perovskite quantum dots (CsPbX3 QDs) (X = Cl, Br, I) have the advantages of adjustable emission position, narrow emission spectrum, high fluorescence quantum efficiency (PLQY), easy preparation, and elevated defect tolerance; therefore, they are widely used in optoelectronic devices, such as solar cells, light-emitting diodes, and lasers. However, their stability still constrains their development due to their intrinsic crystal structure, ionic exchange of surface ligands, and exceptional sensitivity to environmental factors, such as light, water, oxygen, and heat. Therefore, in this paper, we investigate the stability improvement of CsPbX3 QDs and apply fabricated high-efficiency, stable perovskite QDs to solar cells to improve the performance of the cells further. In this paper, we focus on CsPbBr3 QDs with intrinsic extreme stability and optimize CsPbBr3 QDs using strategies, such as Mn+ doping, ligand regulation, and polymer encapsulation, which can improve optical properties while ensuring their stability. The test results show that the above five methods can improve the strength and luminescence performance of QDs, with the best stability achieved when PMMA encapsulates QDs with a ratio of PMMA = 2:1 and PLQY increases from 60.2% to 90.1%.

Research Progress of Green Solvent in CsPbBr3 Perovskite Solar Cells.

In optoelectronic applications, all-Brominated inorganic perovskite CsPbBr3 solar cells have received a great deal of attention because of their remarkable stability and simplicity of production. Most of the solvents used in CsPbBr3 perovskite solar cells are toxic, which primarily hinders the commercialization of the products. In this review, we introduce the crystal structure and fundamental properties of CsPbBr3 materials and the device structure of perovskite cells, summarize the research progress of green solvents for CsPbBr3 PSCs in recent years from mono-green solvent systems to all-green solvent systems, and discuss the approaches to improving the PCE of CsPbBr3 PSCs, intending to facilitate the sustainable development of CsPbBr3 perovskite solar cells. Finally, we survey the future of green solvents in the area of CsPbBr3 perovskite solar cells.

Reduced responses to heroin-cue-induced craving in the dorsal striatum: effects of long-term methadone maintenance treatment.

Methadone maintenance treatment (MMT) is safe and effective for heroin addiction, but the neural basis of the length effects of long-term MMT on brain activity during craving in former heroin addicts is unclear. This study explored it by comparing the brain activations of heroin addicts with different length of MMT during pictorial presentation of heroin-related cue. Fifteen male former heroin addicts successfully treated by MMT less than 1 year (Group A), 15 matched patients with 2-3 year MMT (Group B) and 17 healthy controls underwent functional magnetic resonance imaging while heroin-related and neutral stimuli were present to them. Subjective cue-elicited craving was measured with visual analog scale before and after imaging. Then, partial correlation analysis to reveal the relationship between drug-related blood oxygen level dependent (BOLD) signal intensity and heroin or methadone use history. Finally, self-reported craving was not different between Group A and B before and after scanning. Compared with Group A, Group B had a significant reduced brain activity to heroin-related minus neural cues in the bilateral caudate. After controlling for the variable heroin use history, the drug-related BOLD signal intensity in the bilateral caudate was negatively correlated with MMT duration and total methadone consumption. When MMT history was controlled, the drug-related activity intensity in right caudate had a positive correlation with heroin daily dosage. Long-term MMT may improve heroin-craving response by modulating the impaired function in the bilateral dorsal striatum caused by former heroin use.