Stabilization of Perovskite Solar Cells by a Universal Dilution Strategy: The Crystallization Control of Blade-Coating.

Solvent engineering is one of the most effective strategies to control perovskite film quality, which directly affects the performance of perovskite solar cells (PSCs). Here, we introduce volatile acetonitrile (ACN) into the traditional solvent system (i.e., N,N-dimethylformamide and N-methyl-2-pyrrolidone) to dilute the perovskite precursors from 1.43 M to lower concentration (0.6-0.8 M). The dilution strategy can effectively improve the stability of the precursor solution and maintain similar film quality and device performance as those with high solution concentration (1.43 M). Notably, the devices with low-concentration precursors (0.6-0.8 M) show efficiency of 20.85% and improved long-term (>1000 h) storage stability compared to the device with high precursor concentration by blade-coating. Meanwhile, the material cost can be reduced by more than 50% when diluting to 0.6-0.8 M. These results demonstrate a universal dilution method which can provide guidance for the research and development of low-cost and high stability PSCs.

Cu1.94S-ZnS-CdS ternary heteronanoplates with efficient carrier transfer for enhanced photocatalytic hydrogen evolution.

Incorporating precise morphology control and efficient carrier separation into single-nanoparticle heterojunctions to achieve high photocatalytic efficiency remains a significant challenge. Here, we synthesized Cu1.94S-ZnS-CdS ternary heteronanoplates (HNPs) with a continuous sublattice structure using cation exchange reactions. Femtosecond transient absorption spectroscopy (TAS) confirms that ternary heterojunction enhances carrier separation efficiency, demonstrating both rapid separation (∼0.2 ps) and an extended lifetime (∼1512 ps). The synergistic combination results in a significantly enhanced hydrogen evolution rate of 2.012 mmol·g-1·h-1, which is 17 times and 183 times higher than that achieved by pure CdS and ZnS, respectively. Furthermore, there is no significant decrease in the activity of Cu1.94S-ZnS-CdS in photocatalytic hydrogen evolution after 288 days of placement. Our work offers an alternative approach for designing noble-metal-free photocatalysts with precisely defined materials and interfaces, aiming to enhance both photocatalytic hydrogen evolution efficiency and stability.

Application of smart hydrogel materials in cartilage injury repair: A systematic review and meta-analysis.

OBJECTIVE: Cartilage injury is a common clinical condition, and treatment approaches have evolved over time from traditional conservative and surgical methods to regenerative repair. In this context, hydrogels, as widely used biomaterials in the field of cartilage repair, have garnered significant attention. Particularly, responsive hydrogels (also known as "smart hydrogels") have shown immense potential due to their ability to respond to various physicochemical properties and environmental changes. This paper aims to review the latest research developments of hydrogels in cartilage repair, utilizing a more systematic and comprehensive meta-analysis approach to evaluate the research status and application value of responsive hydrogels. The goal is to determine whether these materials demonstrate favorable therapeutic effects for subsequent clinical applications, thereby offering improved treatment methods for patients with cartilage injuries. METHOD: This study employed a systematic literature search method to summarize the research progress of responsive hydrogels by retrieving literature on the subject and review studies. The search terms included "hydrogel" and "cartilage," covering data from database inception up to October 2023. The quality of the literature was independently evaluated using Review Manager v5.4 software. Quantifiable data was statistically analyzed using the R language. RESULTS: A total of 7 articles were retrieved for further meta-analysis. In the quality assessment, the studies demonstrated reliability and accuracy. The results of the meta-analysis indicated that responsive hydrogels exhibit unique advantages and effective therapeutic outcomes in the field of cartilage repair. Subgroup analysis revealed potential influences of factors such as different types of hydrogels and animal models on treatment effects. CONCLUSION: Responsive hydrogels show significant therapeutic effects and substantial application potential in the field of cartilage repair. This study provides strong scientific evidence for their further clinical applications and research, with the hope of promoting advancements in the treatment of cartilage injuries.

Pluronic F127 hydrogel-loaded extracellular vesicles from adipose-derived mesenchymal stem cells promote tracheal cartilage regeneration via SCNN1B delivery.

Extracellular vesicles (EVs) derived from adipose-derived mesenchymal stem cells (AMSC-EVs) have been highlighted as a cell-free therapy due to their regenerative capability to enhance tissue and organ regeneration. Herein, we aimed to examine the mechanism of PF127-hydrogel@AMSC-EVs in promoting tracheal cartilage defect repair. Based on bioinformatics methods, SCNN1B was identified as a key gene for the osteogenic differentiation of AMSCs induced by AMSC-EVs. EVs were isolated from rat AMSCs and then loaded onto thermo-sensitive PF-127 hydrogel to develop PF127-hydrogel@AMSC-EVs. It was established that PF127-hydrogel@AMSC-EVs could effectively deliver SCNN1B into AMSCs, where SCNN1B promoted AMSC osteogenic differentiation. The promotive effect was evidenced by enhanced ALP activity, extracellular matrix mineralization, and expression of s-glycosaminoglycan, RUNX2, OCN, collagen II, PERK, and ATF4. Furthermore, the in vivo experiments revealed that PF127-hydrogel@AMSC-SCNN1B-EVs stimulated tracheal cartilage regeneration in rats through PERK/ATF4 signaling axis activation. Therefore, PF127-hydrogel@AMSC-SCNN1B-EVs may be a novel cell-free biomaterial to facilitate tracheal cartilage regeneration and cartilage injury repair.

Recent Advances in Laser-Induced Synthesis of MOF Derivatives.

Metal-organic frameworks (MOFs) are crystalline materials with permanent pores constructed by the self-assembly of organic ligands and metal clusters through coordination bonds. Due to their diversity and tunability, MOFs are used as precursors to be converted into other types of functional materials by pyrolytic recrystallization. Laser-induced synthesis is proven to be a powerful pyrolytic processing technique with fast and accurate laser irradiation, low loss, high efficiency, selectivity, and programmability, which endow MOF derivatives with new features. Laser-induced MOF derivatives exhibit high versatility in multidisciplinary research fields. In this review, first, the basic principles of laser smelting and the types of materials for laser preparation of MOF derivatives are briefly introduced. Subsequently, it is focused on the peculiarity of the engineering of structural defects and their applications in catalysis, environmental protection, and energy fields. Finally, the challenges and opportunities at the current stage are highlighted with the aim of elucidating the future direction of the rapidly growing field of laser-induced synthesis of MOF derivatives.

Sintering, Microstructure, and Mechanical Properties of TiTaNbZrHf High-Entropy Alloys Prepared by Cold Isostatic Pressing and Pressure-Less Sintering of Hydrides.

A TiTaNbZrHf refractory high-entropy alloy (RHEA) was synthesized through a cold isostatic pressing and a pressure-less sintering process in a hydrogen atmosphere using a powder mixture of metal hydride prepared either by mechanical alloying (MA) or by rotating mixing. This study investigates how differences in powder particle sizes impact the RHEA's microstructure and mechanical properties. HCP (a = b = 3.198 Å, c = 5.061 Å) and BCC2 (a = b = c = 3.40 Å) phases were observed in the microstructure of coarse powder TiTaNbZrHf RHEAs at 1400 °C. In contrast, fine powder RHEAs were found to possess two-phase structures of HCP and BCC1 (a = b = c = 3.36 Å) with a higher hardness of 431 HV, compression strength of 1620 MPa, and a plasticity of >20%.

Hydrogen reduction of spent lithium-ion battery cathode material for metal recovery: Mechanism and kinetics.

Hydrogen reduction is becoming a promising method for recycling lithium-ion battery cathode materials. However, the reaction mechanism and kinetics during hydrogen reduction are unclear, requiring further investigation. Therefore, non-isothermal and isothermal reduction experiments were conducted to evaluate the temperature dependence of the hydrogen reduction kinetics using simultaneous thermogravimetric and differential thermal analysis equipped with mass spectrometry. XRD and SEM were used to characterize the reduction products to understand the underlying reduction mechanisms. The hydrogen reduction profile could be divided into three main stages: decomposition of cathode materials, reduction of the resultant nickel and cobalt oxides, and reduction of LiMnO2 and residual nickel and cobalt oxides. The hydrogen reduction rate increased with increasing temperature, and 800°C was the optimum temperature for separating the magnetic Ni-Co alloy from the non-magnetic manganese oxide particles. The apparent activation energy for the isothermal tests in the range of 500-700°C was 84.86 kJ/mol, and the rate-controlling step was the inward diffusion of H2(g) within each particle. There was an downward progression of the reduction through the material bed for the isothermal tests in the range of 700-900°C, with an apparent activation energy of 51.82 kJ/mol.

Probing Operator Spreading via Floquet Engineering in a Superconducting Circuit.

Operator spreading, often characterized by out-of-time-order correlators (OTOCs), is one of the central concepts in quantum many-body physics. However, measuring OTOCs is experimentally challenging due to the requirement of reversing the time evolution of systems. Here we apply Floquet engineering to investigate operator spreading in a superconducting 10-qubit chain. Floquet engineering provides an effective way to tune the coupling strength between nearby qubits, which is used to demonstrate quantum walks with tunable couplings, reversed time evolution, and the measurement of OTOCs. A clear light-cone-like operator propagation is observed in the system with multiple excitations, and has a nearly equal velocity as the single-particle quantum walk. For the butterfly operator that is nonlocal (local) under the Jordan-Wigner transformation, the OTOCs show distinct behaviors with (without) a signature of information scrambling in the near integrable system.

A systematic review of gold extraction: Fundamentals, advancements, and challenges toward alternative lixiviants.

Since the birth of cyanidation, it has been dominant in the gold extraction industry. Recently, with the increasing awareness of environmental hazards and potential risks posed by the severe toxicity of cyanide, attempts to seek alternative lixiviants have arisen. Over the past three decades, a significant amount of literature has examined alternative lixiviants to cyanide for recovering gold, while few industrial applications have been reported due to various obstacles, such as toxicity, excessive consumption, or low leaching efficiency. These obstacles are progressively overcome in multiple ways, including process improvement, system optimization, use of co-intensifying systems, and development of additives. In this paper, related studies about alternative lixiviants and methods such as cyanide, thiosulfate, thiourea, thiocyanate, polysulfides, halides, and microbial leaching are summarized. The history, fundamentals, advancements, and challenges of alternative lixiviants are fully concluded to provide a reference for cleaner gold production. In addition, the comprehensive performance of lixiviants was evaluated according to a novel evaluation criterion proposed in terms of economy, efficiency, and environment.

Enabling high energy lithium metal batteries via single-crystal Ni-rich cathode material co-doping strategy.

High-capacity Ni-rich layered oxides are promising cathode materials for secondary lithium-based battery systems. However, their structural instability detrimentally affects the battery performance during cell cycling. Here, we report an Al/Zr co-doped single-crystalline LiNi0.88Co0.09Mn0.03O2 (SNCM) cathode material to circumvent the instability issue. We found that soluble Al ions are adequately incorporated in the SNCM lattice while the less soluble Zr ions are prone to aggregate in the outer SNCM surface layer. The synergistic effect of Al/Zr co-doping in SNCM lattice improve the Li-ion mobility, relief the internal strain, and suppress the Li/Ni cation mixing upon cycling at high cut-off voltage. These features improve the cathode rate capability and structural stabilization during prolonged cell cycling. In particular, the Zr-rich surface enables the formation of stable cathode-electrolyte interphase, which prevent SNCM from unwanted reactions with the non-aqueous fluorinated liquid electrolyte solution and avoid Ni dissolution. To prove the practical application of the Al/Zr co-doped SNCM, we assembled a 10.8 Ah pouch cell (using a 100 µm thick Li metal anode) capable of delivering initial specific energy of 504.5 Wh kg-1 at 0.1 C and 25 °C.

Assessing Long-Term Cycling Stability of Single-Crystal Versus Polycrystalline Nickel-Rich NCM in Pouch Cells with 6 mAh cm-2 Electrodes.

Lithium-ion batteries based on single-crystal LiNi1- x - y Cox Mny O2 (NCM, 1-x-y ≥ 0.6) cathode materials are gaining increasing attention due to their improved structural stability resulting in superior cycle life compared to batteries based on polycrystalline NCM. However, an in-depth understanding of the less pronounced degradation mechanism of single-crystal NCM is still lacking. Here, a detailed postmortem study is presented, comparing pouch cells with single-crystal versus polycrystalline LiNi0.60 Co0.20 Mn0.20 O2 (NCM622) cathodes after 1375 dis-/charge cycles against graphite anodes. The thickness of the cation-disordered layer forming in the near-surface region of the cathode particles does not differ significantly between single-crystal and polycrystalline particles, while cracking is pronounced for polycrystalline particles, but practically absent for single-crystal particles. Transition metal dissolution as quantified by time-of-flight mass spectrometry on the surface of the cycled graphite anode is much reduced for single-crystal NCM622. Similarly, CO2 gas evolution during the first two cycles as quantified by electrochemical mass spectrometry is much reduced for single-crystal NCM622. Benefitting from these advantages, graphite/single-crystal NMC622 pouch cells are demonstrated with a cathode areal capacity of 6 mAh cm-2 with an excellent capacity retention of 83% after 3000 cycles to 4.2 V, emphasizing the potential of single-crystalline NCM622 as cathode material for next-generation lithium-ion batteries.

Enhanced photocatalytic hydrogen production activity of Janus Cu1.94S-ZnS spherical nanoheterostructures.

Photocatalytic hydrogen evolution is one of the most promising approaches for efficient solar energy conversion. The light-harvesting ability and interfacial structure of heterostructured catalysts regulate the processes of photon injection and transfer, which further determines their photocatalytic performances. Here, we report a Janus Cu1.94S-ZnS nano-heterostructured photocatalyst synthesized using a facile stoichiometrically limited cation exchange reaction. Djurleite Cu1.94S and wurtzite ZnS share the anion skeleton, and the lattice mismatch between immiscible domains is ∼1.7%. Attributing to the high-quality interfacial structure, Janus Cu1.94S-ZnS nanoheterostructures (NHs) show an enhanced photocatalytic hydrogen evolution rate of up to 0.918 mmol h-1 g-1 under full-spectrum irradiation, which is ∼38-fold and 17-fold more than those of sole Cu1.94S and ZnS nanocrystals (NCs), respectively. The results indicate that cation exchange reaction is an efficient approach to construct well-ordered interfaces in hybrid photocatalysts, and it also demonstrates that reducing lattice mismatch and interfacial defects in hybrid photocatalysts is essential for enhancing their solar energy conversion performance.

Plasmon-induced ultrafast charge transfer in single-particulate Cu1.94S-ZnS nanoheterostructures.

Recombination centers generated from structural and interfacial defects in nanoheterostructures (NHs) prevent effective photo-induced charge transfer and have blocked the advance of many photoresponsive applications. Strategies to construct high-quality interfaces in NHs are emerging but are limited in the release of interfacial strain and the integrality of the sublattice. Herein, we synthesize single-particulate Cu1.94S-ZnS NHs with a continuous sublattice using a nanoscale cation exchange reaction (CE). Under near-infrared (NIR) radiation (λ = 1500 nm), femtosecond open-aperture (OA) Z-scan measurements are applied to investigate the nonlinear optical features of samples and verify the existence of plasma-induced charge transfer in the Cu1.94S-ZnS NHs system. The resulting charge transfer time (τ CT) of ∼0.091 picoseconds (ps) was confirmed by the femtosecond time-resolved pump-probe technique. Such an ultrafast charge transfer process has been rarely reported in semiconductor-semiconductor NHs. The results suggest that CE can be used as a promising tool to construct well-ordered interfacial structures, which are significant for the performance enhancement of NHs for photon utilization.

Binary mineral sulfides sorbent with wide temperature range for rapid elemental mercury uptake from coal combustion flue gas.

Developing efficient sorbents with rapid kinetics is the main challenge encountered for Hg0 capture from coal combustion flue gas in a sorbent injection scenario. Binary mineral sulfide-based materials combining copper sulfide (CuS) and zinc sulfide (ZnS) to exert their capabilities for Hg0 capture at the low- and high-temperature was for the first time reported for Hg0 removal to realize a wide temperature range sorbents. When the molar ratio between CuS and ZnS was 10%, the as-synthesized 10Cu-Zn nanocomposite exhibited excellent Hg0 uptake rate at 150°C that could degrade 40 µg/m3 of Hg0 to undetectable level at the end of a 60-s experiment with the dosage of only 1 mg. This Hg0 uptake rate is folds higher compared to that when bare CuS or ZnS was adopted alone at this specific temperature. The typical flue gas atmospheres had negligible effect on Hg0 removal over 10Cu-Zn in a short contact time, which further suggests that the binary sorbents were proper to be injected before the electrostatic precipitator system. Moreover, it is found that, by adjusting the ratio between CuS and ZnS, it is potential to develop binary sorbent suiting any temperature conditions that may achieve an exceedingly high Hg0 capture performance. Thus, this work not only justified the candidature of 10Cu-Zn as a promising alternative to traditional activated carbon for Hg0 capture from coal combustion flue gas but also guided the future development of multi-component mineral sulfide-based sorbents for Hg0 pollution remediation from various industrial flue gases.

Enhanced Mechanical and Corrosion Performance by Forming Micro Shear Bands in Cold Forged Mg-Gd-Y-Zr Alloy.

Forging at room temperature was applied on the per-extruded Mg-Gd-Y-Zr alloy to investigate the effect of cold forging on the microstructure, mechanical properties and corrosion resistance of the alloy. Abundant micro shear bands with misorientations of 2-15° were generated in the as forged alloys. Tremendous enhancement in tensile yield strength was achieved after forging. With a quantitative investigation, micro band boundaries were considered to provide a great contribution to the reinforcement. The ultrafine structure resulting from the formation of micro shear bands led to increased corrosion resistance of the alloy.

Recovery of metals from waste printed circuit boards by selective leaching combined with cyclone electrowinning process.

This paper provides a benign process that realized the metals separation and recovery from wPCBs in an efficient and low cost way. The chemical active order and potential-pH diagram of the metals enlightened us to apply stepwise leaching to selective separation of the metals from the wPCBs. The results indicated that the selective separation of Fe, Al, Zn; Sn and Cu can be achieved by the dilute sulfuric acid leaching, displacement leaching using copper sulphate and sulfuric acid leaching with air-oxidization, respectively. Under the optimal conditions, the leaching efficiency of Fe, Al, Zn, Sn and Cu were 92.59%, 90.51%, 89.73%, 1.44% and 0.82%, respectively, in the dilute sulfuric acid leaching. In the displacement leaching, the displacement efficiency of Sn was as high as 95.20%, with little Cu leached. The data of sulfuric acid leaching with air-oxidization experiments shows that the leaching efficiency of Cu reached 95.72%. In order to recover the Sn and Cu in the solutions, the hydrolysis precipitation and cyclone electrowinning were introduced. With these techniques, 92.75% Sn was precipitated and the smooth cathode copper (purity 99.98%) was obtained with the current efficiency was 94.96%. Moreover, the analysis of the mass distribution about the process demonstrated that the H+ and Cu2+ were consumed, but also produced in different procedure, that means the process is a simple and eco-friendly technology, not only due to its high recovery efficiency, but also high reagents recyclable.

Selective C-C Coupling in Carbon Dioxide Electroreduction via Efficient Spillover of Intermediates As Supported by Operando Raman Spectroscopy.

Developing efficient systems for the conversion of carbon dioxide to valuable chemicals using solar power is critical for mitigating climate change and ascertaining the world's future supply of clean fuels. Here, we introduce a mesoscopic cathode consisting of Cu nanowires decorated with Ag islands, by the reduction of Ag-covered Cu2O nanowires prepared via galvanic replacement reaction. This catalyst enables CO2 reduction to ethylene and other C2+ products with a faradaic efficiency of 76%. Operando Raman spectroscopy reveals intermediate formation of CO at Ag sites which undergo subsequent spillover and hydrogenation on the Cu nanowires. Our Cu-Ag bimetallic design enables a ∼95% efficient spillover of intermediates from Ag to Cu, delivering an improved activity toward the formation of ethylene and other C2+ products. We also demonstrate a solar to ethylene conversion efficiency of 4.2% for the photoelectrochemical CO2 reduction using water as electron and proton donor, and solar power together with perovskite photovoltaics to drive the uphill reaction.

Computational Fluid Dynamics Modeling of Combustion Characteristics of a CH4/O2 Combustor in a Copper Anode Furnace.

With the rapid depletion of high-yield copper mineral resources and the accumulation of secondary copper resources, the recycling of secondary copper is gaining popularity in the copper industry. A copper anode furnace, often used in copper recycling, usually relies on methane combustion to melt copper scraps. In this work, a computational fluid dynamics (CFD) model of pure oxy-methane combustion is established to investigate the combustion characteristics of the CH4/O2 combustor in the copper anode furnace. The model is validated by comparing the simulation results with experimental measurements. The effects on flame length and temperature distribution are investigated under various fuel velocities, oxidizer velocities, and oxidizer temperatures. The results indicate that flame length and temperature distribution increase as the fuel velocity and oxidizer temperature increase, and decrease with the increase in oxidizer velocity. The flame length and temperature distribution always show an increasing trend with the increasing equivalence ratio. Based on the recycling capacity of the copper anode furnace, this validated CFD model can be used to optimize the operation parameters for controlling flame length and temperature distribution.

Sequential catalysis enables enhanced C-C coupling towards multi-carbon alkenes and alcohols in carbon dioxide reduction: a study on bifunctional Cu/Au electrocatalysts.

Electrochemical reduction of carbon dioxide (CO2) to multi-carbon products such as ethylene, ethanol and n-propanol offers a promising path for utilization of excessive CO2 and energy storage. Oxide-derived Cu electrodes are among the best electrocatalysts for the selective formation of ethylene and ethanol. However, a large fraction of the faradaic current still goes to hydrogen evolution, even at optimal conditions (electrolyte, potential, etc.). Here we employ the concept of sequential catalysis using judiciously designed CuAu bimetallic catalysts through galvanic exchange between Au3+ and Cu2O nanowires. By controlling the concentration of the Au3+ precursor and the exchange time, Au nanoparticles were evenly dispersed onto the Cu2O nanowires. The optimized oxide-derived CuAu catalyst showed remarkable improvement towards the formation of ethylene, ethanol and n-propanol, in terms of faradaic efficiency and current density. Our analysis of the electrochemical formation of carbon monoxide, ethylene and hydrogen suggests that the presence of Au, an electrocatalyst for CO2-to-CO conversion, helps enhance *CO-coverage on Cu, thus promoting the production of multi-carbon products and suppressing hydrogen formation on the CuAu catalyst. We propose promising strategies for designing electrochemical systems, which would enable the selective and scalable reduction of CO2 to ethylene and ethanol.

Heavy metal redistribution mechanism assisted magnetic separation for highly-efficient removal of lead and cadmium from human blood.

Magnetic nano capture agent (MNCA)-based magnetic separation is considered as a promising approach to rapidly isolate heavy metals from blood. Limited removal efficiency and potential biosafety risks are the major challenges for the clinical use of MNCA-based magnetic separation. Here, we report a highly-efficient MNCA-based magnetic separation of heavy metals from blood in continuous multi-stage adsorption mode. The interactions between MNCA and blood components (e.g. blood cells and plasma proteins) and the MNCA-induced cellular immune responses are studied in detail. The distribution and redistribution of heavy metals in blood are quantitatively analyzed. It demonstrates that concentration dependent redistribution can increase the contact between heavy metals and MNCA, leading to improvement on heavy metal removal efficiency. The removal performance is tested in batch mode and in continuous mode. Results show that 97.97% of Pb and 96.53% of Cd are removed from blood in 120 min using continuous multi-stage adsorption mode, and the residual concentrations of Pb and Cd in blood decrease from 400 µg L-1 to 8.11 µg L-1 and 13.84 µg L-1, respectively. This study paves an effective way for heavy metal intoxication therapy by MNCA-based magnetic separation.