Acidic Environment Research Articles

The impact of pH value on the transfer and release dynamics of doxorubicin facilitated by carbon nanotubes within the capillary network surrounding cancerous tumors through molecular dynamics simulation

Among the pharmacological agents employed in cancer therapy, doxorubicin holds a prominent place due to its widespread use and potent cytotoxic effects and doxorubicin offers considerable promise in combating cancer, its administration requires careful consideration of the delicate balance between therapeutic benefit and potential harm, highlighting the intricate landscape of cancer treatment. Molecular dynamics simulation was used in this research to evaluate the effect of pH on the transfer and release kinetics of doxorubicin via carbon nanotubes within the capillary network surrounding cancer tumors. Upon examination of the acquired data, it became evident that following a duration of 10 ns, the temperature of the scrutinized structure stabilized at 310 K. Additionally, the analysis revealed that over the same period, the potential energy of examined structure reached a convergence point of 5.68 kcal/mol. Moreover, as the pH level increased from 3 to 11, a notable reduction in the maximum velocity of particle motion was detected, diminishing from 0.0028 to 0.0021 Å/fs. This elevation in pH led to a decline in the interaction between the vessel and solute, decreasing from 0.57 to 0.42 kcal/mol. Similarly, the interaction between the vessel and tumor experienced a decline, escalating from 6.95 to 6.05 kcal/mol with the pH increased from 3 to 11. Lastly, the pH elevation resulted in a marked reduction in the rate of drug release, decreasing from 84 to 46 %. This work concluded that MD simulations greatly enhanced the progress of pH-responsive CNT-based drug delivery systems. By offering comprehensive understanding of their behavior in acidic tumor environments, these simulations optimized these systems for targeted cancer treatment.

Corrosion behaviour of 110SS steel in hydrochloric acid and blended acid system at 200°C

The influence of organic acids (formic acid, acetic acid) on the corrosion behaviour of 110SS steel, a hydrogen sulphide corrosion resistant alloy steel, in hydrochloric (HCl) acid environments was studied. The corrosion rates of 110SS steels in HCl acid and blended acid were measured using the high-temperature and high-pressure corrosion tester. Scanning electron microscopy was utilised to observe the morphology of corrosion products on steel samples corroded by different acid systems, and the energy dispersive X-ray spectrometer was used to analyse the elemental composition of the corrosion products. The corrosion morphology was observed using a 3D laser scanner. The results indicated that the corrosion rate of 110SS steel in HCl acid at 200 °C was an exponential function of HCl concentration. Reducing the HCl concentration significantly decreased the corrosion rate of 110SS steel. Organic acids and corrosion inhibitors synergistically reduced the corrosion of 110SS steel in HCl acid. Adding 3 wt.% organic acid to the 15 wt.% HCl acid system further reduced the corrosion rate, with a more pronounced effect observed in the HCl–formic acid system compared to the HCl–acetic acid system. Organic acids chemically adsorbed onto the steel surface and decomposed to produce CO, which hindered the attack of hydrogen ions on the metal. The added corrosion inhibitor and intensifier Sb2O3 resulted in the formation of a compact adsorption film on the steel surface, further inhibiting corrosion. The optimal mass ratio of HCl acid to organic acid was found to be 15% to 3%.

Nutrimental modifications in blueberry (Vaccinium corymbosum L.) caused by vanadium supply

Blueberry plants prosper in acid environments with pH 4.5, condition that enhances vanadium (V) bioavailability. In different species, literature reports nutrimental modifications caused by V, nevertheless in blueberry plants this effect remains unknown. This study assessed the impact of six vanadium (V) doses in nutrient solutions (0, 20, 40, 80, 160 µM) and as foliar sprays (20 µM) on blueberry plants, employing a completely randomized experimental design with three replicates. At 66 days after applying the treatments, nutriments concentrations in leaves, stems and roots of each plant were determinate. Except for N, V modified nutrimental concentrations in at least one plant organ. V applied to foliage benefits Mn (67%) in leaf, as Ca (56%), Mg (40%), B (26%) and Mn (46%) did in stems and P (50%) in roots. No matter V concentration in solution, P (51%), Fe (270%) and Cu (230%) in roots are enhanced, but Mo it is reduced up to 6 times. The use of 160 µM of V in solutions increases Mg (40%) concentrations in stems, the same happened in Ca (32%) and Zn (47%) in roots but reduced K (35%) in this organ. V applied from 0 to 160 µM in solution increases 3, 64, 225 times V concentration in leaf, stem and roots respectively. These results show that V applications in solution benefits P levels in leaf, Ca and Mg in stem, P, Ca and Mg in root; while foliar spray enhances K, Ca, Mg concentration in stem and Mg in root.

PH/Hypoxia dual-stimuli responsive COF nanocarriers with reversible charge conversions for the accurate tumor-targeting and enhanced anticancer drug delivery

Nanoparticles-based drug delivery systems show great promise for cancer therapy due to the advantages of crossing physiological barrier, high drug availability and good stability. However, deep tumor penetration, long blood circulation, and rapid drug release remain intractable problems for nanocarriers. In this work, we report a tumor microenvironment-sensitive nanodrug delivery system containing both acidic pH and hypoxia response sites to achieve enhanced drug permeability and on-demand release for precise cancer therapy. The covalent organic frameworks (COFs) with introduced azobenzene (azo) groups were used as employed as nanocarrier, and modified by pH-sensitive sulfamide-based zwitterionic polymers (PBA), followed by loading with the chemotherapeutic drug doxorubicin (DOX) to obtain COF-PBA@DOX. Copolymer PBA achieved charge conversions in tumor acidic environment, resulting in a positive charge on the nanocarrier surfaces, thus facilitating the augmented tumor accumulation. Meanwhile, azo which was formed the COF carrier, could be reduced to amines by the highly expressed azoreductase under tumor hypoxia conditions, resulting in nanoparticle dissociation and the drug-controlled release at the solid tumor sites. The fabricated dual-responsive nanomedicine, based on the surface charge-reversal of zwitterion in the acidic environment of tumor, can realize the accumulation and targeted drug release at the tumor site, which has great potential as a nanocarrier in tumor therapy.

Addressing Soil Acidity Challenges: Promoting Tea Production as Alternative Crop in Ethiopia -- Review

The prevalence of acidic soils in Ethiopia presents a significant obstacle to improving agricultural productivity and restricts the implementation of sustainable farming practices that could enhance food security. Acidic soils are typically defined by their high concentration of hydrogen ions and a lack of essential nutrients, which collectively create an environment that is less conducive to the growth of many vital staple crops. Consequently, farmers faced with these conditions often struggle to achieve optimal yields, which exacerbates food scarcity and undermines economic stability. To effectively combat the issues posed by acidic soils, it is imperative to adopt targeted soil management strategies that are specifically designed to address these challenges. This may include the implementation of soil reclamation techniques that aim to neutralize soil acidity and restore nutrient balance. Additionally, comprehensive initiatives must be undertaken to promote agricultural resilience, which could involve the cultivation of alternative crops that are better suited to thrive in acidic conditions, such as tea. This paper aims to provide a thorough examination of several key aspects related to the development and management of acidic soils in Ethiopia. It will investigate into the processes that contribute to the formation of acid soils, as well as the various types of acid soil present in the country, explore the distribution of acidic soils throughout Ethiopia, highlighting areas that are particularly affected and the implications for local farming practices. Furthermore, the analysis will address the specific impact of soil acidity on crop growth, yield, and quality. It will investigate how soil acidity influences the availability of essential nutrients for plants, thereby affecting the overall health and productivity of crops grown in these conditions. The promotion of tea production in Ethiopia is another critical topic that tea cultivation not only offers a viable alternative crop but also presents opportunities for economic development and diversification in agricultural systems. The mechanisms that confer aluminum resistance in tea plants will be discussed, as well as the ways in which aluminum can stimulate growth in these crops, thereby illustrating the unique resilience of tea plants in acidic environments. By addressing these complex issues holistically, the paper seeks to contribute valuable insights and foster a deeper understanding of how to navigate the challenges posed by acidic soils in the Ethiopian agricultural landscape.

The corrosion performance for ultrafine WC-12Co processed by heat treatments in different pH solutions

The corrosion performance of WC-12Co after different post heat treatments (1100 °C, 1100 °C + 400 °C, 1100 °C + 500 °C, 1100 °C + 600 °C), were tested in 0.05 M H2SO4, 0.1 M Na2SO4, and 0.1 M NaOH. Heat treatments influence the corrosion performance of WC-12Co in acidic and neutral environments. However, the corrosion properties for WC-12CO in alkaline solutions are independent of the heat treatments. W and C diffuse to Co from the quenching process, dramatically improving corrosion resistance, with higher annealing temperature slightly reduces the corrosion performance. The rank of corrosion nucleation parameter tested by EIS and potentio-dynamic polarisation, with the corrosion expansion rate measured by potentio-static polarisation at +0.2 VSCE, + 0.5 VSCE, and + 0.8 VSCE for 30 min are not the same. The corrosion mechanism tested in different pH values is analysed using SEM, XPS, and DFT calculations.

Bimetallic MoFe phosphide catalysts for the hydrogen evolution reaction

In this work, highly efficient and stable (bi)metallic phosphides were prepared by a facile, flexible, and controllable sol-gel method followed by sintering. This novel approach allowed to avoid complicated and dangerous phosporization using, e.g. red phosphorus. The doping of the MoP catalysts with Fe was used to further boost their catalytic performance. Monometallic MoP and Mo3P, as well as bimetallic MoFeP were tested in both acidic and alkaline environments and showed remarkable results. The incorporation of Fe enabled the creation of a scalable and cost-effective catalyst for the hydrogen evolution reaction due to the synergy between Fe and Mo in the bimetallic phosphides. Using MoFeP for catalysing the hydrogen evolution reaction, overpotentials of only -132 mV (in an acidic medium) and -142 mV (in an alkaline medium) were needed to reach current density of -10 mA.cm−2, indicating the possibility of use this catalyst in a large pH range. Its high catalytic activity was maintained even at current density of -100 mA.cm−2 as documented by overpotentials of -202 mV and -246 mV in acid and alkaline environment, respectively. This, along with excellent stability and durability confirms its promising potential for incorporation into industrially relevant applications. The experimental data were confirmed by computational (DFT) results, showcasing that incorporation of Fe caused an increase in the number of active sites with Gibbs adsorption energy close to zero.

A Novel Bi-Directional Channel for Nutrient Uptake across Mycobacterial Outer Envelope.

Nutrients are absorbed by special transport proteins on the cell membrane; however, there is less information regarding transporters across the mycobacterial outer envelope, which comprises dense and intricate structures. In this study, we focus on the model organism Mycolicibacterium smegmatis, which has a cell envelope similar to that of Mycobacterium tuberculosis, as well as on the TiME protein secretion tube across the mycobacterial outer envelope. We present transcriptome results and analyze the protein compositions of a mycobacterial surface envelope, determining that more transporters and porins are induced to complement the deletion of the time gene in Mycolicibacterium smegmatis. The TiME protein is essential for nutrient utilization, as demonstrated in the uptake experiments and growth on various monosaccharides or with amino acids as the sole carbon source. Its deletion caused bacteria to be more sensitive to anti-TB drugs and to show a growth defect at an acid pH level, indicating that TiME promotes the survival of M. smegmatis in antibiotic-containing and acidic environments. These results suggest that TiME tubes facilitate bi-directional processes for both protein secretion and nutrient uptake across the mycobacterial outer envelope.

PH modulates efficiency of singlet oxygen production by flavin cofactors.

Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) are frequently used interchangeably in the catalysis of various reactions as part of flavoenzymes because they have the same functional component, the isoalloxazine ring. However, they differ significantly in their conformational properties. The inclusion of two planar rings in the structure of FAD greatly increases the range of possible conformations compared to FMN. An exemplary instance of this is the remarkable disparity in singlet oxygen efficiency production, Φ Δ, between FMN and FAD. Under neutral pH conditions, FAD has low photosensitizing activity with Φ Δ ∼ 0.07 while FMN demonstrates high photosensitizing activity with Φ Δ ∼ 0.6. Both adenine rings and isoalloxazine in FAD contain pH titratable groups. Through comprehensive analysis of the kinetics of the transient absorbance of the triplet state and the phosphorescence of singlet oxygen from FAD and FMN, we determined the correlation between different conformational states and the pH-dependent generation of singlet oxygen. Based on our findings, we may deduce that within the pH range of pH 2 to pH 13, only two out of the five potential structural states of FAD are capable of efficiently producing singlet oxygen. There are two open conformations: (i) an acidic FAD conformation with a protonated adenine ring, which is around 10 times more populated than the neutral open FAD conformation, and (ii) a neutral pH FAD conformation, which is significantly less populated. The FAD conformer with a protonated adenine ring at acidic pH generates singlet oxygen with approximately 50% efficiency compared to the constantly open FMN at neutral pH. This may have implications for singlet oxygen synthesis in acidic environments.

Membrane-camouflaged biomimetic nanoplatform with arsenic complex for synergistic reinforcement of liver cancer therapy.

Aim: Arsenic has excellent anti-advanced liver cancer effects through a variety of pathways, but its severe systemic toxicity forces the need for a safe and effective delivery strategy.Methods: Based on the chelating metal ion properties of polydopamine (PDA), arsenic was immobilized on an organic carrier, and a M1-like macrophage cell membrane (MM)-camouflaged manganese-arsenic complex mesoporous polydopamine (MnAsOx@MP@M) nanoplatform was successfully constructed. MnAsOx@MP@M was evaluated at the cellular level for tumor inhibition and tumor localization, and in vivo for its anti-liver cancer effect in a Hepa1-6 tumor-bearing mouse model.Results: The nanoplatform targeted the tumor site through the natural homing property of MM, completely degraded and released drugs to kill tumor cells in an acidic environment, while playing an immunomodulatory role in promoting tumor-associated macrophages (TAMs) repolarization.Conclusion: MnAsOx@MP@M has synergistically enhanced the targeted therapeutics against liver cancer via nanotechnology and immunotherapy, and it is expected to become a safe and multifunctional treatment platform in clinical oncology.

Acidity-Actuated Polymer/Calcium Phosphate Hybrid Nanomotor (PCaPmotor) for Penetrating Drug Delivery and Synergistic Anticancer Immunotherapy.

Tumor acidity-driven nanomotors may offer robust propulsion for tumor-specific penetrating drug delivery. Herein, an acidity-actuated poly(amino acid) calcium phosphate (CaP) hybrid nanomotor (PCaPmotor) was designed, using a mPEG-PAsp-PPhe@THZ531 micelle (Poly@THZ) for CaP mineralization accompanied by αPD-L1 antibody encapsulation. Dissolution of the CaP layer in an acidic tumor environment gave off heat energy to propel the nanomotor to augment the cellular uptake and penetration into deeply seated cancer cells while facilitating αPD-L1 release. THZ531 delivered by the PCaPmotor inhibited CDK12 and its down-streamed phosphorylation of RNAP-II to increase the cancer immunogenicity events such as the DNA damage, cell apoptosis, immunogenic cell death, lysosomal function disturbance, and MHC-I upregulation. THZ531 and αPD-L1 cosupplied by PCaPmotor significantly increased the frequency of DCs maturation and intratumoral infiltration of CTLs, but the two free drugs did not. Consequently, the PCaP@THZ/αPD-L1 nanomotor resulted in synergistic anticancer immunotherapy in mice. This acid-actuated PCaPmotor represented a new paradigm for penetrating drug delivery.

Investigation of effects of environmental conditions on wear behaviors of glass fiber reinforced polyester composite materials

AbstractGlass fiber reinforced polymer (GFRP) composites can be subjected to different environmental conditions such as temperature, humidity, ultraviolet radiation, hydrothermal cycle, acidic and alkaline solution in environments where they operate. These environmental conditions cause different damage mechanisms in composites such as pore formation, micro‐cracks, delamination, fiber breakage, fiber/matrix interface separation, plasticization, swelling and surface color change. In this study, wear properties of hybrid glass fiber reinforced polymer composites exposed to various environmental conditions for constant load (60 N), speed (500 rpm) and 2 h were examined comprehensively, depending on material content and environmental conditions. In this experimental study, the service conditions in glass fiber reinforced composites were simulated using different artificial aging environments such as acidic environment, hydrothermal cycle and UV radiation. In addition to the material content, it appears that the environmental conditions to which composites are exposed has a significant effect on friction coefficient. Considering environmental conditions, it is seen that the acid environment and hydrothermal cycle have reduced wear resistance of GFRP composites, while UV radiation improved wear resistance of the composites. In C2 sample, the wear rates under different conditions are 1.87 × 10−14 m3/Nm in non‐treated sample, 6.05 × 10−14 m3/Nm in acid environment, 4.79 × 10−14 m3/Nm in hydrothermal cycle and 0.59 × 10−14 m3/Nm in UV radiation.Highlights Friction coefficient of glass fiber reinforced polyester (GFRP) is higher under aged condition compared to non‐treated. Glass fibers used in correct proportions can reduce friction coefficient in GFRP. GFRP exposed to environmental conditions has an important effect on wear. Acid environment and hydrothermal cycle has reduced wear resistance of GFRP. UV radiation improved wear resistance of GFRP composite.

Cu(Ⅱ)-EDTA degradation and copper recovery from wastewater in wide pH ranges by an electrooxidation-capacitive deionization system

The treatment and recovery of metal resources from complex industrial wastewater has posed significant challenges due to the presence of multiple heavy metal ions, heavy metal complexes, and acidic conditions. In this study, a novel electrooxidation-capacitive deionization (EO-CDI) system was proposed, which ingeniously harnessed the unheeded Faraday side reaction in capacitive deionization for simultaneous degradation and recovery of copper complexes from wastewater through two electrode integration. Specially, the cathode CuS0.78Se0.22 synthesized through the anionic Se-substitution strategy exhibited a remarkable adsorption capacity up to 672.02 mg/g for Cu ions, outstanding selectivity and stability, particularly in acidic environments. The water oxidation process occurring at the activated carbon anode played a crucial role by generating active species that contribute to the degradation of Cu(Ⅱ)-EDTA, which leaded to the release of copper ions, facilitating their subsequent recovery. Cyclic experiments further confirmed the excellent cyclic stability of the hybrid EO-CDI system, along with its impressive performance in copper extraction when applied to real industrial wastewater. This innovative approach offered promising prospects for addressing the challenges associated with the treatment of complex industrial wastewater and the recovery of valuable metal resources.

Comprehending Spatial Distribution and Controlling Mechanisms of Groundwater in Topical Coastal Aquifers of Southern China Based on Hydrochemical Evaluations

Groundwater quality and availability in coastal aquifers have become a serious concern in recent times due to increased abstraction for domestic, agricultural and industrial purposes. (1) Background: Zhuhai city is selected as a representative coastal aquifer in Southern China to comprehensively evaluate the hydrochemical characteristics, spatial distribution and controlling mechanisms of groundwater. (2) Methods: A detailed study utilizing statistical analyses, a Piper diagram, Gibbs plots, and ion ratios was conducted on 114 surface water samples and 211 groundwater samples. (3) Results: The findings indicate that the pH of most groundwater is from 6.06 to 6.52, indicating a weakly acidic environment. The pH of surface water ranges from 5.35 to 9.86, with most values being weakly alkaline. The acidity in the groundwater may be related to the acidic atmospheric precipitation, an acidic unsaturated zone, oxidation of sulphide minerals and tidal action. The groundwater chemical types are predominantly mixed, followed by Ca-Mg-HCO3 type. Surface water samples are predominantly Na-Cl-SO4 type. The NO3− concentration in groundwater is relatively high, with a mean value of 17.46 mg/L. The NO2− and NH4+ concentrations in groundwater are relatively low, with mean values of 0.46 mg/L and 7.58 mg/L. (4) Conclusions: The spatial distribution of the principal chemical constituents in the groundwater is related to the landform. The chemical characteristics of groundwater in the study area are mainly controlled by the weathering and dissolution of silicate and sulfate minerals, evaporation, seawater mixing and cation exchange. Nitrate in clastic fissure groundwater, granite fissure groundwater and unconfined pore groundwater primarily originates from atmospheric precipitation, agricultural activities of slope farmland and forest land. Nitrate in confined pore groundwater and karst groundwater primarily originates from domestic sewage and mariculture wastewater. Our findings elucidate the processes characterizing the hydrogeology and surface water interactions in Zhuhai City’s coastal system, which are relevant to other catchments with similar geological characteristics.

In-Situ Product Removal for the Enzymatic Depolymerization of Poly(ethylene terephthalate) via a Membrane Reactor.

Poly(ethylene terephthalate) (PET) is a common single-use plastic and a major contributor to plastic waste. PET upcycling through enzymatic depolymerization has drawn significant interests, but lack of robust enzymes in acidic environments remains a challenge. This study investigates in-situ product removal (ISPR) of protons from enzymatic PET depolymerization via a membrane reactor, focusing on the ICCG variant of leaf branch compost cutinase. More than two-fold improvements in overall PET depolymerization and terephthalic acid yields were achieved employing ISPR for an initial PET loading of 10 mgPET mlbuffer-1. The benefit of ISPR was reduced for a lower initial loading of 1 mgPET mlbuffer-1 due to decreased need for pH stabilization of the enzyme-containing solutions. A back-of-envelop analysis suggests that at a modest dilution ratio, ISPR could help achieve savings on caustic base solutions used for pH control in a bioreactor. Our study provides valuable insights for future ISPR developments for enzymatic PET depolymerization, addressing the pressing need for more sustainable solutions towards plastic recycling and environmental conservation.

A cheminformatics and network pharmacology approach to elucidate the mechanism of action of Mycobacterium tuberculosis γ-carbonic anhydrase inhibitors.

Mycobacterium tuberculosis (Mtb) carbonic anhydrases (CAs) are critical enzymes that regulate pH by converting CO2 to HCO3 -, essential for Mtb's survival in acidic environments. Inhibiting γ-CAs presents a potential target for novel antituberculosis drugs with unique mechanisms of action. This study aimed to explore the biological connections underlying Mtb pathogenesis and investigate the mechanistic actions of antituberculosis compounds targeting the Cas9 protein. We employed homology modeling and virtual screening to identify compounds with high binding affinities for Cas9 protein. This study used the homology modeling approach employing high-quality AlphaFold DB models for γ-CA. Furthermore, the systems biology approach was used for analyzing the integrated modelling of compounds, integrating data on genes, pathways, phenotypes, and molecular descriptors. Single-cell RNA sequencing was also conducted to profile gene expression. Three compounds, F10921405, F08060425, and F14437079, potentially binding to Cas9 protein, have been identified. F10921405 and F08060425 showed significant overlap in their effects on pathways related to the immune response, while F14437079 displayed distinct mechanistic pathways. Expression profiling revealed high levels of genes such as PDE4D, ROCK2, ITK, MAPK10, and SYK in response to F1092-1405 and F0806-0425, and MMP2 and CALCRL in response to F1443-7079. These genes, which play a role in immune modulation and lung tissue integrity, are essential to fight against Mtb. The molecular relationship and pathways linked to the mentioned compounds give the study a holistic perspective of targeting Mtb, which is essential in designing specific therapeutic approaches. Subsequent research will involve experimental validation to demonstrate the efficacy of the promising candidates in Mtb infections.

Two-dimensional ferroelastic semiconductors InXY (X = S, Se; Y = Cl, Br, I): Promising candidates for photocatalytic water splitting with tunable electronic anisotropy

We have identified a class of two-dimensional ferroelastic monolayers, denoted as InXY (where X = S, Se; Y = Cl, Br, I), through first-principles calculations. The dynamic, thermal, and mechanical stabilities of these InXY monolayers are validated by phonon dispersion spectra, AIMD calculations, and elastic constants, respectively. These monolayers exhibit semiconducting behavior with bandgaps ranging from 1.94 to 2.85 eV and possess excellent ferroelasticity with strong ferroelastic signals and moderate ferroelastic switching barriers. Notably, the band edge positions of InSBr and InSI monolayers are observed to stride the water redox potentials at pH = 0, indicating their potential as photocatalysts for water splitting in acidic environments. We also explored the effects of biaxial strain on the band edge alignments and photocatalytic performance of these monolayers. Moreover, the InXY monolayers exhibit excellent anisotropic optical absorption across the visible to ultraviolet regions, along with high anisotropic carrier transport. The coupling of ferroelastic and anisotropic properties in these monolayers offers promising opportunities for designing controllable electronic devices, thereby expanding their potential applications in multifunctional materials. Our findings reveal that the InXY monolayers are promising candidates for efficient photocatalytic water splitting and controllable optoelectronic applications.

Modulating Carrier Oxygen Vacancies to Enhance Strong Oxide‐Support Interaction in IrO2/Nb2O5‐x Catalysts for Promoting Acidic Oxygen Evolution Reaction

AbstractGiven the pronounced dissolution of electrocatalysts in acidic environments, the quest for effective oxygen evolution reaction (OER) electrocatalysts suitable for proton exchange membrane (PEM) water electrolyzers persists as a formidable challenge. In this investigation, catalysts are synthesized by creating oxygen vacancies within various metal oxides (Nb2O5‐x, Ta2O5‐x, ZrO2‐x, TiO2‐x) through plasma‐assisted method, thereby facilitating the immobilization of IrO2 onto these defect‐rich surfaces. The findings unveil that IrO2/Nb2O5‐x manifests reduced overpotentials during acidic OER, achieving an overpotential down to 225 mV@10 mA cm−2, coupled with outstanding durability at multicurrent densities exceeding 200 h, attributed to strong oxide‐support interaction (SOSI) between the IrO2 catalyst and Nb2O5‐x substrate. Density functional theory (DFT) computations uncover intensified binding affinities between IrO2 and Nb2O5‐x, thus modulating the central energy levels of Ir's d orbitals toward favorable OER conditions, consequently bolstering the electrocatalytic activity and stability of the composite catalyst. Furthermore, employing IrO2/Nb2O5‐x as a PEM electrolyzer anode enables consistent operation at 1000 mA cm−2 for 200 h, with an Ir content of only 0.2852 mg cm−2 and an energy consumption of 4.34 kWh Nm−3 H2. This achievement substantially lowers the cost of hydrogen production to US$ 0.96 per kilogram, underscoring its potential for practical applications.

Efficient recovery of lithium from shale gas wastewater: Fe, Ni, and Al doping of H1.33Mn1.67O4 for improved adsorption capacity and manganese loss reduction

To minimize manganese loss during acid leaching and to enhance the lithium adsorption capacity from shale gas wastewater of H1.33Mn1.67O4, this adsorbent material was doped with metallic elements in this study. Doping was achieved using solid-phase synthesis, resulting first in a Li1.33RXMn1.67−XO4 (R = Fe, Ni, Al) precursor powder through high-temperature calcination. Then, lithium was leached out under acidic environment to obtain the desired H1.33RXMn1.67−XO4 (HMO-R) adsorbents. The equilibrium adsorption capacities of HMO-R powders were measured as 20.7 mg/g, 20.7 mg/g, and 29.0 mg/g, for Fe, Ni, and Al dopants, respectively, surpassing that of the former H1.33Mn1.67O4 (13.7 mg/L). Moreover, an average reduction of manganese loss by 30% for HMO-R was observed during lithium recovery/extraction cycles by acid leaching compared to undoped Li1.33Mn1.67O4. Overall, the doped adsorbent exhibited a stable crystal structure and high adsorption capacity, enhanced stability, performance, and efficiency in cycling experiments with respect to the undoped material.

Enhanced corrosion resistance of a novel periodic multilayered Si/(Si, N)-DLC coating against simulated coal mine water

In this study, a novel periodic multilayered DLC coating, which was composed of a Si interlayer and a Si/N co-incorporated DLC layer (Si/(Si, N)-DLC) per period, was deposited; the corrosion behavior under the neutral, acidic, or alkaline coal mine water environment and its periodic number dependence, especially the fundamental corrosion mechanism, were systemically explored. Results suggest that compare to the substrate, the introduction of multilayered Si/(Si, N)-DLC coating presents a dramatic enhancement in the corrosion resistance under coal mine water environment. However, with increasing the periodic number, the corrosion resistance of the multilayered coating strongly depends on the working environment, which exhibits an enhancement in neutral and alkaline environments while a degeneration in acidic environment. This is attributed to not only the prolongation of the corrosion path caused by the multilayered structure but also the formation of an insulating silicon oxide layer in neutral and alkaline environments. However, in acidic environments, the strong permeability of H+ with the smallest ionic radius easily infiltrates the inherent defects of the coating. This not only weakens the protective properties of the multilayer structure but also leads to hydrogen-induced cracking, ultimately diminishing corrosion resistance. These findings theoretically guide the development of the DLC coatings with excellent corrosion resistance for coal mine applications.