Over the past few decades, photocatalysis technology has received extensive attention because of its potential to mitigate or solve energy and environmental pollution problems.Designing novel materials with outstanding photocatalytic activities has become a research hotspot in this field. In this study, we prepared a series of photocatalysts in which BiOCl nanosheets were modified with carbon quantum dots (CQDs) to form CQDs/BiOCl composites by using a simple solvothermal method. The photocatalytic performance of the resulting CQDs/BiOCl composite photocatalysts was assessed by rhodamine B and tetracycline degradation under visible-light irradiation. Compared with bare BiOCl, the photocatalytic activity of the CQDs/BiOCl composites was significantly enhanced, and the 5 wt% CQDs/BiOCl composite exhibited the highest photocatalytic activity with a degradation efficiency of 94.5% after 30 min of irradiation. Moreover, photocatalytic N2 reduction performance was significantly improved after introducing CQDs. The 5 wt% CQDs/BiOCl composite displayed the highest photocatalytic N2 reduction performance to yield NH3 (346.25 μmol/(g h)), which is significantly higher than those of 3 wt% CQDs/BiOCl (256.04 μmol/(g h)), 7 wt% CQDs/BiOCl (254.07 μmol/(g h)), and bare BiOCl (240.19 μmol/(g h)). Our systematic characterizations revealed that the key role of CQDs in improving photocatalytic performance is due to their increased light harvesting capacity, remarkable electron transfer ability, and higher photocatalytic activity sites.
This work reports a novel CQDs/BiOCl composite photocatalyst for efficiently removing contaminants from water.
Fuel design is a complex multi-objective optimization problem in which facile and robust methods are urgently demanded. Herein, a complete workflow for designing a fuel blending scheme is presented, which is theoretically supported, efficient, and reliable. Based on the data distribution of the composition and properties of the blending fuels, a model of polynomial regression with appropriate hypothesis space was established. The parameters of the model were further optimized by different intelligence algorithms to achieve high-precision regression. Then, the design of a blending fuel was described as a multi-objective optimization problem, which was solved using a Nelder–Mead algorithm based on the concept of Pareto domination. Finally, the design of a target fuel was fully validated by experiments. This study provides new avenues for designing various blending fuels to meet the needs of next-generation engines.
A major challenge is to construct ceramic membranes with tunable structures and functions for water treatment. Herein, a novel corrosion-resistant polymer-derived silicon oxycarbide (SiOC) ceramic membrane with designed architectures was fabricated by a phase separation method and was applied in organic removal via adsorption and oxidation for the first time. The pore structure of the as-prepared SiOC ceramic membranes was well controlled by changing the sintering temperature and polydimethylsiloxane content, leading to a pore size of 0.84–1.62 μm and porosity of 25.0–43.8%. Corrosion resistance test results showed that the SiOC membranes sustained minimal damage during 24 h exposure to high-intensity acid–base conditions, which could be attributed to the chemical inertness of SiOC. With rhodamine 6G (R6G) as the model pollutant, the SiOC membrane demonstrated an initial effective removal rate of 99% via adsorption; however, the removal rate decreased as the system approached adsorption saturation. When peroxymonosulfate was added into the system, efficient and continuous degradation of R6G was observed throughout the entire period, indicating the potential of the as-prepared SiOC membrane in oxidation-related processes. Thus, this work provides new insights into the construction of novel polymer-derived ceramic membranes with well-defined structures and functions.
All-solid-state lithium-metal batteries (ASSLMBs) are widely considered as the ultimately advanced lithium batteries owing to their improved energy density and enhanced safety features. Among various solid electrolytes, sulfide solid electrolyte (SSE) Li6PS5Cl has garnered significant attention. However, its application is limited by its poor cyclability and low critical current density (CCD). In this study, we introduce a novel approach to enhance the performance of Li6PS5Cl by doping it with fluorine, using lithium fluoride nanoparticles (LiFs) as the doping precursor. The F-doped electrolyte Li6PS5Cl-0.2LiF(nano) shows a doubled CCD, from 0.5 to 1.0 mA/cm2 without compromising the ionic conductivity; in fact, conductivity is enhanced from 2.82 to 3.30 mS/cm, contrary to the typical performance decline seen in conventionally doped Li6PS5Cl electrolytes. In symmetric Li|SSE|Li cells, the lifetime of Li6PS5Cl-0.2LiF(nano) is 4 times longer than that of Li6PS5Cl, achieving 1500 h vs. 371 h under a charging/discharging current density of 0.2 mA/cm2. In Li|SSE|LiNbO3@NCM721 full cells, which are tested under a cycling rate of 0.1 C at 30 °C, the lifetime of Li6PS5Cl-0.2LiF(nano) is four times that of Li6PS5Cl, reaching 100 cycles vs. 26 cycles. Therefore, the doping of nano-LiF offers a promising approach to developing high-performance Li6PS5Cl for ASSLMBs.
PPMG-based composite electrolytes were fabricated via the solution method using the polyvinyl alcohol and polyvinylpyrrolidone blend reinforced with various contents of sulfonated inorganic filler. Sulfuric acid was employed as the sulfonating agent to functionalize the external surface of the inorganic filler, i.e., graphene oxide. The proton conductivities of the newly prepared proton exchange membranes (PEMs) were increased by increasing the temperature and content of sulfonated graphene oxide (SGO), i.e., ranging from 0.025 S/cm to 0.060 S/cm. The induction of the optimum level of SGO is determined to be an excellent route to enhance ionic conductivity. The single-cell performance test was conducted by sandwiching the newly prepared PEMs between an anode (0.2 mg/cm2 Pt/Ru) and a cathode (0.2 mg/cm2 Pt) to prepare membrane electrode assemblies, followed by hot pressing under a pressure of approximately 100 kg/cm2 at 60 °C for 5–10 min. The highest power densities achieved with PPMG PEMs were 14.9 and 35.60 mW/cm2 at 25 °C and 70 °C, respectively, at ambient pressure with 100% relative humidity. Results showed that the newly prepared PEMs exhibit good electrochemical performance. The results indicated that the prepared composite membrane with 6 wt% filler can be used as an alternative membrane for applications of high-performance proton exchange membrane fuel cell.
Because of the low reactivity of cyclic nitrides, liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior applications. In this study, we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation, which effectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets (CCN NSs) during hydrothermal reaction. Under a large specific surface area and increased light absorption, these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO2 reduction, increasing the CO production rate by approximately tenfold compared with hexagonal melamine (h-Me). Moreover, the product selectivity of CCN NSs reaches up to 93.5% to generate CO from CO2. Furthermore, the annealed CCN NSs exhibit a CO conversion rate of up to 95.30 μmol/(g h), which indicates an 18-fold increase compared with traditional carbon nitride. During the CCN NS synthesis, nitrogen-doped carbon quantum dots (NDC QDs) are simultaneously produced and remain suspended in the supernatant after centrifugation. These QDs disperse well in water and exhibit excellent luminescent properties (QY = 67.2%), allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04 µmol/L. Notably, the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-effective and highly efficient process, yielding products with superior capabilities for catalytic conversion of CO2 and pollutant detection, respectively.