The adaptability, distribution, ecological function and restoration application of biological soil crusts on metal tailings: A critical review.

A large amount of metal tailings causes many environmental issues. Thus, the techniques for their ecological restoration have garnered extensive attention. However, they are still in the exploratory stage. Biological soil crusts (BSCs) are a coherent layer comprising photoautotrophic organisms, heterotrophic organisms and soil particles. They are crucial in global terrestrial ecosystems and play an equal importance in metal tailings. We summarized the existing knowledge on BSCs growing on metal tailings. The main photosynthetic organisms (cyanobacteria, eukaryotic algae, lichens, and mosses) of BSCs exhibit a high heavy metal(loid) (HM) tolerance. BSCs also have a strong adaptability to other adverse conditions in tailings, such as poor structure, acidification, and infertility. The literature about tailing BSCs has been rapidly increasing, particularly after 2022. The extensive literature confirms that the BSCs distributed on metal tailings, including all major types of metal tailings in different climatic regisions, are common. BSCs perform various ecological functions in tailings, including HM stress reduction, soil structure improvement, soil nutrient increase, biogeochemical cycle enhancement, and microbial community restoration. They interact and accelerate revegetation of tailings (at least in the temperate zone) and soil formation. Restoring tailings by accelerating/inducing BSC formation (e.g., resource augmentation and inoculation) has also attracted attention and achieved small-scale on-site application. However, some knowledge gaps still exist. The potential areas for further research include the relation between BSCs and HMs, large-scale quantification of tailing BSCs, application of emerging biological techniques, controlled laboratory experiments, and other restoration applications.

Doping engineering in S-scheme composite for Regulating the selectivity of photocatalytic CO2 reduction.

Regulating product selectivity in photocatalytic CO2 reduction to enhance the yield of valuable hydrocarbons remains a formidable challenge because of the diversity of reduction products and the competitive reduction of H2O. Herein, ultrathin Bi2O3/ Co-doped SrBi4Ti4O15 S-scheme photocatalysts (Co-BS) were synthesized using a hydrothermal method. The Bi2O3/Co-doped SrBi4Ti4O15 photocatalyst exhibited significantly higher selectivity for CH4 (62.3 µmolg-1) and CH3OH (54.1 µmolg-1) in CO2 reduction compared with pure SrBi4Ti4O15 (27.2 and 0.8 µmolg-1) and the Bi2O3/SrBi4Ti4O15 S-scheme without Co (30.2 and 0 µmolg-1). The experimental results demonstrated that the inclusion of Co into SrBi4Ti4O15 expanded the range of light absorption and generated an internal electric field between Co-doped SrBi4Ti4O15 and Bi2O3. Density functional theory calculations and other experimental findings confirmed the formation of a new doping energy level in the Bi2O3/SrBi4Ti4O15 S-scheme heterojunction after Co doping. The valence band electrons of Bi2O3/SrBi4Ti4O15 transitioned to the Co-doped level because of the interconversion between Co3+ and Co2+ under the action of the internal electric field. Furthermore, the corresponding characterizations revealed that the adsorption and electron transfer rates of the surface active sites were accelerated after Co doping, enhancing electron involvement in the photocatalytic reaction process. This study presented a metal-doped S-scheme heterojunction approach for CO2 reduction to produce high-value products, enhancing the conversion of solar energy into energy resources.

Transcriptomic and Physiological Responses of Chlorella pyrenoidosa during Exposure to 17α-Ethinylestradiol.

17α-ethinylestradiol (17α-EE2) is frequently detected in water bodies due to its use being widespread in the treatment of prostate and breast cancer and in the control of alopecia, posing a threat to humans and aquatic organisms. However, studies on its toxicity to Chlorella pyrenoidosa have been limited to date. This study investigated the effects of 17α-EE2 on the growth, photosynthetic activity, and antioxidant system of C. pyrenoidosa and revealed related molecular changes using transcriptomic analysis. The cell density of algae was inhibited in the presence of 17α-EE2, and cell morphology was also altered. Photosynthetics were damaged, while reactive oxygen species (ROS), superoxide dismutase (SOD), and malondialdehyde (MDA) content increased. Further transcriptomic analysis revealed that the pathways of photosynthesis and DNA replication were affected at three concentrations of 17α-EE2, but several specific pathways exhibited various behaviors at different concentrations. Significant changes in differentially expressed genes and their enrichment pathways showed that the low-concentration group was predominantly impaired in photosynthesis, while the higher-concentration groups were biased towards oxidative and DNA damage. This study provides a better understanding of the cellular and molecular variations of microalgae under 17α-EE2 exposure, contributing to the environmental risk assessment of such hazardous pollutants on aquatic organisms.

Hot-Casting Large-Grain Perovskite Film for Efficient Solar Cells: Film Formation and Device Performance.

Organic-inorganic metal halide perovskite solar cells (PSCs) have recently been considered as one of the most competitive contenders to commercial silicon solar cells in the photovoltaic field. The deposition process of a perovskite film is one of the most critical factors affecting the quality of the film formation and the photovoltaic performance. A hot-casting technique has been widely implemented to deposit high-quality perovskite films with large grain size, uniform thickness, and preferred crystalline orientation. In this review, we first review the classical nucleation and crystal growth theory and discuss those factors affecting the hot-casted perovskite film formation. Meanwhile, the effects of the deposition parameters such as temperature, thermal annealing, precursor chemistry, and atmosphere on the preparation of high-quality perovskite films and high-efficiency PSC devices are comprehensively discussed. The excellent stability of hot-casted perovskite films and integration with scalable deposition technology are conducive to the commercialization of PSCs. Finally, some open questions and future perspectives on the maturity of this technology toward the upscaling deposition of perovskite film for related optoelectronic devices are presented.

Off-Stoichiometric Methylammonium Iodide Passivated Large-Grain Perovskite Film in Ambient Air for Efficient Inverted Solar Cells.

Hot-casting is a promising technique of depositing high-quality organic-inorganic hybrid perovskite thin films with large crystal grain size. Here, we reported the that the crystallinity and grain size of perovskite films could be systematically tailored by modulating the stoichiometry of the precursor solution in the hot-casting process under ambient condition with a relative humidity of 40%. It was found that a slight excess of methylammonium iodide (MAI) in the precursor solution could effectively compensate the MAI loss due to the high substrate temperature. A significant increase in the grain size and crystallinity of the perovskite film was observed together with a decrease in defect density and a carrier concentration enhancement in MAI-rich samples. The corresponding devices exhibited a notable increase in fill factor (up to 80.70%) and short-circuit current density. In addition, in MAI-deficient samples, an enrichment of PbI2 at the grain boundaries was directly observed by optical microscopy and laser confocal microscopy. Time-resolved photoluminescence spectroscopy revealed an increase in the charge carrier lifetime in the MAI-deficient samples, which was in line with the previous results with a small amount of excess PbI2 in the perovskite film. This work highlights a new strategy to prepare high-quality perovskite thin films with excellent crystal quality under ambient condition.