Alkaline Solution Research Articles

Experimental Study on Energy-Free Superhydrophobic Radiative Cooling Versatile Film with Enhanced Environmental Tolerance.

Clean, energy-free methods of cooling are an effective way to respond to the global energy crisis. To date, cooling materials using passive daytime radiative cooling (RC) technology have been applied in the fields of energy-efficient buildings, solar photovoltaic cooling, and insulating textiles. However, RC materials frequently suffer from comprehensive damage to their microstructure, resulting in the loss of their initial cooling effect in complex outdoor environments. Here, a superhydrophobic daytime passive RC porous film with environmental tolerance (SRCP film) was fabricated, which integrated strong solar reflectivity (approximately 90%), mid-infrared emissivity (approximately 0.97), and superhydrophobicity (water contact angle (WCA) of 160° and sliding angle of 3°). This study revealed that SRCP film had an average reflectivity of 14.3% higher than SiO2 particles in the 0.3-2.5 μm wavelength region, achieving a cooling effect of 13.2 °C in ambient conditions with a solar irradiance of 946 W·m-2 and a relative humidity of 74% due to the synergistic effect of effective solar reflection and thermal infrared emission. In addition, empirical results showed that the attained films possessed outstanding environmental tolerance, maintaining high WCA (156°), stable cooling effect (8.3 °C), and low SiO2 loss (less than 5.1%) after 30 consecutive days of UV irradiation and 14 days of corrosion with acidic and alkaline solutions. More importantly, this work could be flexibly prepared by various methods without the use of any fluorine-containing reagents, which greatly widens the practical application scope.

Adipose Stem Cell Response to Borophosphate Bioactive Glass

Silicate and borate bioactive glasses have been reported to create alkaline conditions by rapidly releasing ions when reacting in aqueous solution. At certain levels, this alkaline solution can negatively affect cell viability. Adding phosphate ions to the glass composition can control the degradation rate of bioactive glasses and create a neutral pH environment. This study evaluated a series of borophosphate bioactive glasses (BPBGs) with nominal molar compositions 16Na2O-24CaO-xB2O3-(60-x)P2O5, where x = 0, 40, or 60. The phosphate (X0) glass (PBG) produced an acidic solution when dissolved in water; the borate (X60) glass (BBG) produced an alkaline solution, and the BPBG glass produced a pH-neutral solution. These three glasses were evaluated using adipose stem cells (ASCs), a cell population known for their therapeutic abilities. The effects of each glass on the pH of cell culture, ions released during degradation, and on ASC functions, including viability, migration, angiogenic ability, differentiation, and protein secretions, were evaluated. The X40 BPBG created a physiologically neutral pH in cell culture media after 24 h. The X0 phosphate glass promoted ASC migration, while the highly alkaline X60 borate increased the angiogenic ability of ASCs. These results indicate that BPBG can be used safely in cell culture studies and customized for specific biomedical applications.

A p-n-p Configuration Based on the Cuprous Oxide/Silicon Tandem Photocathode for Accelerating Solar-Driven Hydrogen Evolution.

Photoelectrochemical splitting of water into hydrogen is a potential route to motivate the application of solar-driven conversion to clean energy but is regularly limited by its low efficiency. The key to addressing this issue is to design a suitable photocathode configuration for high-efficiency photogenerated carrier separation and transmission to photocathode-surface reaction sites. In this work, we report a Si-Cu2O tandem photocathode featuring a p-n-p configuration for solar-driven hydrogen evolution in an alkaline solution. Driven by this built-in field, the electrons induced from Si were transferred through FeOOH, which acted as electron tunnels, to combine with the holes from Cu2O, triggering more electrons generated from Cu2O to particiate in the surface reaction. Under simulated sunlight, the optimized photocathode achieved and maintained a photocurrent density of -11 mA/cm2 at 0 VRHE in alkaline conditions for 120 min, outperforming the reported tandem cell consisting of Si and Cu2O photocathodes. Our results provide valuable insight into a feasible way to construct an optimized photocathode for efficient solar-driven H2 evolution.

A new study on the effects of clay nanoparticles on the corrosion performance of Al-Si-Cu matrix composites in both acidic and alkaline solutions

A new study on the effects of clay nanoparticles on the corrosion performance of Al-Si-Cu matrix composites in both acidic and alkaline solutions

Development of geopolymer mortar made from bagasse ash with waste aluminum

Geopolymer concrete is a type of concrete that is produced using industrial waste materials such as fly ash, slag, and other similar materials instead of traditional Portland cement. This research studied the variables affecting geopolymer mortar from bagasse ash mixed with aluminum scraps. The waste materials, bagasse ash (BA) and aluminium scrap (AL) were crushed to reduce the particles by grinding. An amount of ALU 0.01 – 0.15 wt% bagasse (BA) ash was added to the mixture. The alkaline solutions (AS) used to leach silicon oxide and aluminium oxide from BA were sodium hydroxide (NH) and sodium silicate (NS). The concentration of NH solution was varied between 7.5 – 15 molar. The ratio of alkaline solution to bagasse ash (AS/BA) was controlled at 0.50. Mortar samples were cast and cured at 60 80 and 100 °C for 48 hours. The results showed that the 10-molar sodium hydroxide solution tended to support the higher compressive strength. The highest compressive strength of geopolymer was found when using 0.04% aluminum scrap and curing at 80 °C. The additional water improved the workability of the fresh mortar, but the lower strength of the geopolymers was archived. GRAPHICAL ABSTRACT HIGHLIGHTS Do not use as a cementitious binder Reuse waste materials It is an environmentally friendly and sustainable material

Enhanced corrosion protection of rebars in alkaline solutions by ferroporphyrin and the mechanisms of electron consumption and lattice reconstruction

Abstract Reinforced concretes are the primary materials in coastal and offshore engineering. In alkaline environment of concrete, the anodic process is passivation of rebars and the conjugated cathodic process is oxygen reduction reaction (ORR). It is proposed that a novel approach to enhance the passivation films through catalyzed ORR by iron meso-tetra(4-carboxyphenyl)porphine (FeTCPP). The ORR catalyst FeTCPP promotes the formation of passivation film, as it accelerates the consumption of abundant electrons generated and accumulated by the anodic formation of passivation films. The passivation films of rebars are highly defective Fe3O4 semiconductor. The dissolution of interstitial ferrous ions and lattice iron ions produces defects of O ion vacancies, Fe ion vacancies and interstitial Fe ions, and they further cause the formation and accumulation of Fe atom vacancies on the metal surface, leading to the collapse of the passivation films. The FeTCPP adsorbs on the surface of passivation films, hindering the dissolution of lattice iron ions and interstitial ferrous ions, thereby inhibiting the generation and accumulation of Fe atom vacancies and improving the integrity and protective ability of the passivation films.

Occurrence of Sphingomonas olei with elemental S oxidation capability in sodic soil: Potential role in sodicity reclamation and plant growth promotion

The success of the sodic soil reclamation using elemental S (S°) depends on the population of the native S° oxidizers. Augmenting the native flora of the sodic soils with effective S° oxidizers can enhance the success of the sodic soil reclamation. Present study reports for the first time the S° oxidation potential of the Sphingomonas olei strain 20UP7 isolated from sodic soils with pHs 9.8 and ECe 3.6 dS m–1. Inoculation with S. olei strain 20UP7 caused 13.0–24.2 % increase in S° oxidation in different sodic soils (pHs 9.1–10.5). It improved the concentration of the Ca2+, Mg2+, PO43– and declined the HCO3– and total alkalinity of the soil solution. This isolate also showed appreciable P and Zn solubilization, indole acetic acid, ammonia, and titratable acidity production in the growth media. It tended to the formation of biofilm around sulphur particles. The PCR amplification with gene–specific primers showed the occurrence of soxA, soxB, and soxY genes with a single band corresponding to length of 850, 460, and 360 base pairs, respectively. The integration of the S. olei strain 20UP7 with S° caused 21.7–25.4 % increase in the rice and wheat yield compared to the soil treated with S° alone. This study concludes that the S. olei, native to high saline–sodic soils can be utilized for improving the sodicity reclamation and plant growth promotion using elemental S based formulations.

Zero Voltage-Degradation of Li2MnO3 with Ultrathin Amorphous Li─Mn─O Coating.

Manganese-based lithium-rich layered oxides (Mn-LLOs) are promising candidate cathode materials for lithium-ion batteries, however, the severe voltage decay during cycling is the most concern for their practical applications. Herein, an Mn-based composite nanostructure constructed Li2MnO3 (LMO@Li2MnO3) is developed via an ultrathin amorphous functional oxide LixMnOy coating at the grain surface. Due to the thin and universal LMO amorphous surface layer etched from the lithiation process by the high-concentration alkaline solution, the structural and interfacial stability of Li2MnO3 are enhanced apparently, showing the significantly improved voltage maintenance, cycle stability, and energy density. In particular, the LMO@Li2MnO3 cathode exhibits zero voltage decay over 200 cycles. Combining with ex situ spectroscopic and microscopic techniques, the Mn2+/4+ coexisted behavior of the amorphous LMO is revealed, which enables the stable electrochemistry of Li2MnO3. This work provides new possible routes for suppressing the voltage decay of Mn-LLOs by modifying with the composite functional unit construction.

Alkaline hydrogenotrophic methanogenesis in Methanococcus vannielii at low carbon dioxide concentrations

Capture of carbon dioxide from the atmosphere is challenging and thermodynamically expensive because of its dilute concentration (421 ppm, December 2023). Utilizing the concentrating effect of dissolving atmospheric CO2 in alkaline solution to form dissolved inorganic carbon (DIC), we explored the potential of an alkalotolerant hydrogenotrophic methanogen, Methanococcus vannielii, to capture and convert CO2 at low partial pressures to methane. Kinetic constants for CO2 reduction to CH4 were determined from experiments in serum bottles at low pCO2 at 30˚C. At pH 7, 8, and 9, the apparent KM is 0.4, 1.2, and 1.2 mM DIC and the apparent vmax is 5.6, 7.8, and 2.9 mmol CH4 L−1 OD−1 hr−1, respectively. Using atmosphere-equilibrated DIC concentrations at pH 7, 8, and 9, methane formation rates were 1.1, 2.3, and 2.1 mmol CH4 L−1 OD−1 hr−1, respectively. Our data show that alkaline hydrogenotrophic methanogenesis is an alternative to photosynthetic CO2 fixation for biological capture and conversion of CO2 at atmospheric concentrations at reasonable rates.

NC Loaded PtM Alloy from M-NC with Ultralow Pt Loading for Oxygen Reduction Reaction

Abstract Developing low Pt or non-precious metal catalysts for oxygen reduction reaction (ORR) has becoming necessary in recent years. Herein, PtM alloy anchored on nitrogen-doped carbon (PtM/NC, M=Fe, Co) catalyst with ultralow Pt loading (~1 wt%) is prepared from the simple two-process pyrolysis, namely from C to M-NC then to PtM/NC. The as-prepared PtM/NC (M=Fe, Co) shows an excellent ORR catalytic performance with the peak potential and half-wave potential of 0.901 and 0.870 V for PtFe/NC, 0.868 and 0.845 V for Pt3Co/NC. The ORR on PtM/NC (M=Fe, Co) is a mainly direct 4-electron reaction pathway (3.75-3.90) in alkaline solution. Moreover, they possess good methanol tolerance and stability. Synergistic effect of Pt and M together with N species result in the excellent ORR catalytic activity of PtM/NC (M=Fe, Co). The negative shift of Pt binding energy caused by both lattice contraction and electron orbital coupling from M is beneficial for reducing the d-band center of Pt, weakening the oxygen binding energy and enhancing the ORR intrinsic activity of Pt. The strong interactions between NC and PtM alloy are beneficial for anchoring PtM nanoparticles, promoting the stability of catalyst. This work provides a new strategy for preparing ultralow Pt loading catalysts.

Electrochemical Non-Enzymatic Glucose Sensing Platform Based on Vanadium Pentoxide Film-Modified Screen Printed Gold Electrode

A screen printed gold electrode (SPGE) served as the foundation for directly depositing Vanadium pentoxide (V2O5), crafting an enzyme-free glucose sensor. Through cyclic voltammetry in an alkaline setting, the sensor's ability to drive glucose oxidation was explored. Utilizing V2O5 as an electrocatalyst, this non-enzymatic sensor exhibited an expansive linear detection range (1 mM–10 mM) and an impressively low detection limit of 0.9 μM. These results underscored V2O5's robust electrocatalytic process in facilitating glucose oxidation within alkaline solutions, unaffected notably by substances like ascorbic acid, fructose and maltose. This investigation highlights a direct and efficient method for glucose detection without reliance on enzymes.

Sustainable Snail‐Inspired Bio‐Based Adhesives with Ultra‐High Adhesion

AbstractAdhesives play a crucial role in modern everyday applications, prompting a growing environmental consciousness regarding their source, composition, utilization, and disposal. Sustainability concerns are frequently generated due to the complex or energy‐intensive manufacturing processes in the production of conventional water‐based adhesives. Here, a coacervate‐based snail‐inspired solvent‐free adhesive (SFA) is engineered by strategically modulating electrostatic interactions and molecular entanglement of two polypeptides under environmentally friendly conditions. The SFA has a record‐breaking adhesion strength of 28 MPa on ceramics, setting a new standard for bio‐based adhesives. The SFA demonstrates robust adhesion performance across a wide temperature ranging from −150 to 300 °C and allows for reusability without compromising adhesion properties. Moreover, it can be easily removed using a non‐toxic alkaline solution. The study presents a promising opportunity for developing high‐performance, reusable adhesives made from renewable materials suitable for industrial applications, relics repair, and even spacecraft processing.

Facile construction of multifunctional 3D smart MOF-based polyurethane sponges with photocatalytic ability for efficient separation of oil-in-water emulsions and co-existing organic pollutant

Water resources are increasingly being damaged by human activities, and it is crucial to deal effectively with polluted water resources. Due to the diversity of pollution sources (oil, organic dyes, and other complex pollutants), it makes sense to develop a material that can handle these pollutants simultaneously. In this article, we construct a simple and fast method to fabricate multifunctional superhydrophobic polyurethane sponges (PU). A superhydrophobic composite coating constructed from ZIF-8, polydimethylsiloxane (PDMS), and stearic acid (SA) was attached to the surface of the polyurethane sponge by a simple impregnation method. Through the above process, we have successfully integrated oil–water separation, photocatalysis, and superhydrophobicity into a polyurethane sponge. The results showed that the PDMS/SA/ZIF-8 polyurethane sponge (PSZPU) had a high hydrophobicity angle (162.9 ± 1.1°). In addition, PSZPU maintains high oil–water separation performance (mean value of separation efficiency > 94.24 %) and superhydrophobicity after oil–water separation cycling tests and a series of harsh environmental tests in acidic and alkaline solutions, high temperatures, abrasion, and UV aging irradiation. Overall, the creation of PSZPU provides a new application for superhydrophobic sponges in water resource treatment.

Ultrasound-Assisted Alkaline Pretreatment of Biomass to Enhance the Extraction Yield of Valuable Chemicals

As a renewable and sustainable resource, lignocellulosic biomass serves as a crucial raw material for the production of biofuels, biochemicals, and various value-added products. This paper aims to develop and optimize a mild alkaline treatment of sawdust assisted by ultrasound, along with enzymatic hydrolysis of the pretreated material. The alkaline sonochemical pretreatment emerged as the optimal approach to enhance the susceptibility of cellulose to subsequent enzymatic hydrolysis to improve the yield of reducing sugars. A comparative study was performed using various ultrasonic applicators (horn and bath) and conventional assisted alkaline pretreatment. The ultrasonic-assisted pretreatment revealed a higher delignification of 68% (horn) and 57% (bath) compared with conventional pretreatment. Processes were optimized using a statistical analysis based on a 23 factorial design. The ratios between sawdust and alkaline solution (RSL = 0.5–1.5 g/100 mL), US amplitude (A = 20–60%), and working temperature (t = 30–50 °C) were selected as process factors. The optimal operating conditions to maximize the reducing sugar yield (138.15 mg GE/gsubstrate) were found as follows: a solid/liquid ratio of RSL,opt = 1.25 g/100 mL, US amplitude of Aopt = 60%, and pretreatment temperature of topt = 50 °C. The overall outcomes clearly confirmed the intensification of delignification by ultrasound-assisted alkaline pretreatment.

Polydopamine supporting method fabricating vanadium nitride nanoparticle enclosed into hierarchical hollow carbon nanospheres for supercapacitors

Nanostructure is crucial for achieving electrode materials with high capacity and high-power ascribing to pleasing specific surface area, intrinsic safety, and satisfactory ion transport pathways; nevertheless, the structural collapse that occurs during high-temperature treatment may lead to a decrease in the specific surface area of the electrode material, causing technical obstacles, and hence affecting its practical applicability. Vanadium nitride has become a promising electrode material since its superior conductivity and desirable theoretical capacity; unfortunately, its practical application is hindered by its limited rate capability, cycle stability, and tendency to dissolve in alkaline solutions. In this study, a template-free method is employed to prepare hollow nanosphere structures through the self-supporting effect of dopamine. When subjected to high-temperatures, it can successfully hinder the collapse of the hollow nanostructures. Graded vanadium nitride nanoparticles are generated in this process and encapsulated in hollow nanostructures. The issues of vanadium nitride dissolution and low transport rate in alkaline electrolytes can be efficiently resolved by leveraging the self-supporting action of dopamine and the subsequent formation of hierarchical vanadium nitride nanoparticles. The anode material endows a capacity of 387.14 F g−1 at a current density of 0.5 A g−1, as well as a coulombic efficiency of 98.28 % even after 10, 000 cycles at a current density of 3 A g−1. Additionally，the assembled device can achieve a maximum power density of 4, 000 W kg−1 and an energy density of 22.89 Wh Kg−1. This anode material displays potential applications in energy storage devices and offers a novel approach to material preparation.

Environmental response characteristics of epitaxial superconducting La0.8Sr0.2NiO2 thin films

Despite the discovery of superconducting properties in thin films with an infinite-layer structured nickelate has paved the way for exploring unconventional superconductivity, opening up new possibilities in this field. However, the challenges related to fabricating these samples have greatly restricted research in this area. In this study, we successfully fabricated superconducting thin films of La0.8Sr0.2NiO2 and investigated their tolerance to different environmental factors. To analyze the stability of the superconducting La0.8Sr0.2NiO2 thin films, we assessed their tolerance to temperature by examining the peak intensities in X-ray diffraction (XRD) and monitoring the changes in resistance curves at varying temperatures. In addition, we investigated the films’ sensitivity to acidity and alkalinity by immersing them in acidic and alkaline solutions for various durations. We also studied the stability of the thin films under various conditions, including heating in air, heating in a vacuum, exposure to acid and alkali, as well as exposure to the organic solvent acetone solution. Our findings highlight the successful preparation of superconducting La0.8Sr0.2NiO2 thin films and shed light on their stability in different environments. This research provides valuable insights for further exploration of their potential applications and laid the foundation for advancements in the field of unconventional superconductivity.

Rechargeable Zn-H2O hydrolysis battery for hydrogen storage and production.

Reactive metals hydrolysis offers significant advantages for hydrogen storage and production. However, the regeneration of common reactive metals (e.g., Mg, Al, etc.) is energy-intensive and produces unwanted byproducts such as CO2 and Cl2. Herein, we employ Zn as a reactive mediator that can be easily regenerated by electrolysis of ZnO in an alkaline solution with a Faradaic efficiency of > 99.9%. H2 is produced in the same electrolyte by constructing a Zn-H2O hydrolysis battery consisting of a Zn anode and a Raney-Ni cathode to unlock the Zn-H2O reaction. The entire two-step water splitting reaction with a net energy efficiency of 70.4% at 80 oC and 50 mA cm-2. Additionally, the Zn-H2O system can be charged using renewable energy to produce H2 on demand and runs for 600 cycles only sacrificing 3.76% energy efficiency. DFT calculations reveal that the desorption of H* on Raney-Ni (-0.30 eV) is closer to zero compared with that on Zn (-0.87 eV), indicating a faster desorption of H* at low overpotential. Further, a 24 Ah electrolyzer is demonstrated to produce H2 with a net energy efficiency of 65.5%, which holds promise for its real application.

Rechargeable Zn‐H2O hydrolysis battery for hydrogen storage and production

Reactive metals hydrolysis offers significant advantages for hydrogen storage and production. However, the regeneration of common reactive metals (e.g., Mg, Al, etc.) is energy‐intensive and produces unwanted byproducts such as CO2 and Cl2. Herein, we employ Zn as a reactive mediator that can be easily regenerated by electrolysis of ZnO in an alkaline solution with a Faradaic efficiency of > 99.9%. H2 is produced in the same electrolyte by constructing a Zn‐H2O hydrolysis battery consisting of a Zn anode and a Raney‐Ni cathode to unlock the Zn‐H2O reaction. The entire two‐step water splitting reaction with a net energy efficiency of 70.4% at 80 oC and 50 mA cm‐2. Additionally, the Zn‐H2O system can be charged using renewable energy to produce H2 on demand and runs for 600 cycles only sacrificing 3.76% energy efficiency. DFT calculations reveal that the desorption of H* on Raney‐Ni (‐0.30 eV) is closer to zero compared with that on Zn (‐0.87 eV), indicating a faster desorption of H* at low overpotential. Further, a 24 Ah electrolyzer is demonstrated to produce H2 with a net energy efficiency of 65.5%, which holds promise for its real application.

Characterization of geopolymer composites for 3D printing: a microstructure approach

Given the importance of geopolymer in terms of 3D printing performance and the scarcity of information on the subject, as well as previous research findings, the purpose of this study is to propose a design methodology for geopolymer concrete mix that can be used in the 3D printing process by studying the effect of fine aggregate size and type, binder type (either slag or metakaolin) and ratio (slag/metakaolin), and alkaline solution amount and ratio (NaOH/Na2SiO3). The study concluded that MK has lower fluidity than BFS under the same conditions that used the same amount of SP. However, it can be improved by adding slag. The best dosage was chosen, which is 50% MK and 50% BFS. Because of these proportions, the mixture is very dense, homogeneous and compact, which increases its microstructure analysis behavior.

Induced Aggregation, Solvent Regulation, and Supracluster Assembly of Aluminum Oxo Clusters.

ConspectusRecent years have witnessed the development of cluster materials as they are atomically precise molecules with uniform size and solution-processability, which are unattainable with traditional nanoparticles or framework materials. The motivation for studying Al(III) chemistry is not only to understand the aggregation process of aluminum in the environment but also to develop novel low-cost materials given its natural abundance. However, the Al-related clusters are underdeveloped compared to the coinage metals, lanthanides, and transition metals. The challenge in isolating crystalline compounds is the lack of an effective method to realize the controllable hydrolysis of Al(III) ions. Compared with the traditional hydrolysis of inorganic Al(III) salts in highly alkaline solutions and hydrolysis of aluminum trialkyl compounds conducted carefully in an inert operating environment, we herein developed an effective way to control the hydrolysis of aluminum isopropanol through an alcoxalation reaction. By solvothermal/low melting point solid melting synthesis and using "ligand aggregation, solvent regulation, and supracluster assembly" strategies, our laboratory has established an organic-inorganic hybrid system of aluminum oxo clusters (AlOCs). The employment of organic ligands promotes the aggregation and slows the hydrolysis of Al(III) ions, which in turn improves the crystallization process. The regulation of the structure types can be achieved through the selection of ligands and the supporting solvents. Compared with the traditional condensed polyoxoaluminates, we successfully isolated a broad range of porous AlOCs, including aluminum molecular rings and Archimedes aluminum oxo cages. By studying ring expansion, structural transformation, and intermolecular supramolecular assembly, we demonstrate unique and unprecedented structural controllability and assembly behavior in cluster science. The advancement of this universal synthetic method is to realize materials customization through modularly oriented supracluster assembly. In this Account, we will provide a clear-cut definition and terminology of "ligand aggregation, solvent regulation, and supracluster assembly". Then we will discuss the discovery in this area by using a strategy, such as aluminum molecular ring, ring size expansion, ring supracluster assembly, etc. Furthermore, given the internal and external pore structures, as well as the solubility and modifiability of the AlOCs, we will demonstrate their potential applications in both the solid and liquid phases, such as iodine capture, the optical limiting responses, and dopant in polymer dielectrics. The strategy herein can be applied to extensive cluster science and promote the research of main group element chemistry. The new synthetic method, fascinating clusters, and unprecedented assembly behaviors we have discovered will advance Al(III) chemistry and will also lay the foundation for functional applications.