Conventional cutting fluids often rely on non-renewable mineral oils and hazardous additives, raising serious environmental and occupational safety concerns. Developing green, high-performance alternatives is therefore imperative for advancing sustainable manufacturing. Amphiphilic Fe3O4@SiO2-C12 core-shell nanoparticles were synthesized and used to stabilize vegetable oil-in-water Pickering emulsions as novel nano-cutting fluids. Systematic characterization confirmed the successful formation of superparamagnetic nanoparticles with tunable wettability. Response surface methodology (RSM) optimized the formulation to pH 8.9, 2.9 wt% cottonseed oil, and 0.18 wt% nanoparticles, achieving a zeta potential of −42.533 mV and wear scar diameter of 0.393 mm. The optimized Pickering emulsion demonstrated superior performance versus the commercial cutting fluid, including a low friction coefficient of 0.0666, a 17.09% reduction in wear scar diameter, a 10.21% decrease in tapping torque, and a 15.40% enhancement in thermal conductivity (0.645 W/(m·K)). X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM)-energy-dispersive spectroscopy (EDS) revealed a triple synergistic lubrication mechanism involving physical adsorption, tribochemical Fe2O3/FeO film formation, and nanoparticle-enabled micro-bearing and heat conduction. The Pickering emulsion also demonstrated excellent magnetic responsiveness, enabling rapid, magnetically controlled demulsification and oil-water separation for recycling. In this work, a high-performance and environmentally friendly cutting fluid was developed and evaluated for sustainable manufacturing applications.

Electrochemical catalysis serves as the cornerstone for a sustainable future, enabling clean energy conversion and advancing green chemical synthesis. Understanding and designing catalysts help us develop more efficient catalysts. This paper systematically summarizes the regulatory mechanisms of the coordination environment in typical electrocatalytic reactions, covering oxygen reduction reactions (ORRs), oxygen evolution reactions (OERs), hydrogen evolution reactions (HERs), carbon dioxide reduction reactions (CO2RRs), and nitrogen reduction reactions (NRRs). It focuses on elucidating the concepts of different ligand types, coordination numbers, coordination configurations, and local geometries, as well as their varying effects on the electronic structure of active sites, the adsorption behavior of reaction intermediates, and the modulation of reaction pathways. This review first classifies and summarizes various strategies for regulating the coordination environment from the perspective of catalysts. Subsequently, starting from the mechanism of each reaction and focusing on the rate-determining steps, it summarizes the central role of the coordination environment in regulating key reaction intermediates, reducing energy barriers, and promoting multi-electron transfer processes. It also outlines common coordination-based regulation strategies and the preparation methods for different reaction types. Furthermore, this paper summarizes recent advances in enhancing catalytic activity, selectivity, and stability through coordination environment regulation strategies, while also discussing the challenges and future directions in this field. Ultimately, the aim is to provide an in-depth analysis of catalyst performance from the perspective of the coordination environment and to offer guidance for catalyst design.

Developing high-performance, eco-friendly cutting fluids is essential for sustainable manufacturing. This work prepared a novel vegetable oil-based Pickering emulsion cutting fluid stabilized by Fe3O4@SiO2-C-8 core-shell nanoparticles, whose surface wettability was tailored via octylsilane grafting. A three-factor, three-level Box-Behnken design coupled with response surface methodology was employed to optimize the formulation using Friction Index and Cooling Index as dual responses. The regression models exhibited high prediction accuracy (R-2 > 0.98) and statistical significance (p < 0.0001). The optimal formulation was determined as contact angle 79.076 degrees, soybean oil content 5.381 wt%, and nanoparticle concentration 0.211 wt%. Under these conditions, the optimized emulsion achieved a coefficient of friction of 0.0787, wear scar diameter of 0.454 mm, and thermal conductivity of 0.602 W/(m & centerdot;K), corresponding to improvements of 11.38%, 5.88%, and 8.80% relative to a commercial fluid. Mechanistic analyses verified the formation of a robust Fe2O3/FeO-SiO2 composite tribofilm via tribochemical reactions, combined with nanoparticle micro-bearing effect and thermal bridge action. This green fluid provides a promising alternative to conventional petroleum-based cutting fluids.

Pesticides and antibiotics from agricultural activities represent a major source of water pollution. While photocatalysis shows promise in eliminating individual pollutants, its behavior and degradation mechanisms in binary pollutant systems remain poorly understood. In this work, using biochar/g-C3N4 as the photocatalyst, the k values for the degradation of typical pesticides and antibiotics, namely azoxystrobin (AZO), tetracycline (TC), ofloxacin (OFX), sulfadiazine (SDZ), and atrazine (ATR), were 0.14144, 0.14467, 0.24850, 0.03145, and 0.01337 min(-1), respectively. The-ln(k) values were positively correlated with the LUMO-HOMO gaps of these pollutants. Interestingly, in AZO-based binary systems, the-ln(k) value of AZO was negatively correlated with the LUMO-HOMO gaps of the coexisting pollutants. Through density functional theory (DFT) calculations and UHPLC-Q Exactive MS analysis, five key intermediates of AZO degradation were identified, most of which were predicted to be less toxic than the parent compound. To enable practical water purification application and facilitate catalyst recovery, a BCN-PVDF photocatalytic purification membrane was fabricated. Under continuous operation for 12 h, the membrane achieved nearly complete removal of TC and OFX, 91.17% removal of AZO, and over 73% removal of SDZ and ATR. It also exhibited excellent anti-fouling and self-cleaning performance. This work elucidates structure-activity relationships in photocatalytic degradation of organic pollutants, reveals interaction mechanisms in binary pollutant systems, and demonstrates a feasible pathway toward the practical purification treatment of complex wastewater containing mixed contaminants.

Traditional mineral oil-based cutting fluids are increasingly incompatible with sustainable manufacturing due to their environmental and health impacts. To solve these challenges, this work presented a green and scalable strategy for a high-performance nano-cutting fluid by constructing a plant-based Pickering emulsion. This system innovatively utilized cottonseed oil as the base oil, stabilized by oleylamine (OA) modified MoS2 nanosheets (MoS2-OA) at the oil-water interface. The formulation was rationally designed and optimized by response surface methodology (RSM) to synergistically enhance emulsion stability, lubrication, and heat dissipation. The resulting Pickering emulsion is demonstrated to possess a unique combination of significantly reduced friction and wear, along with improved thermal conductivity, outperforming a commercial cutting fluid. Mechanistic analysis revealed that MoS2-OA nanosheets formed a multifunctional interfacial film, which synergistically served as a “lubrication film” for low friction and a “thermal bridge” for efficient heat dissipation. Thus, a novel paradigm for developing sustainable metalworking fluids is established by leveraging the synergistic potential of non-edible plant oils and functional nanomaterials.

Ni-based catalysts are extensively studied for the dry reforming of methane (DRM), which converts CO2 and CH4-the two most abundant greenhouse gases-into syngas for downstream chemical synthesis. The harsh reaction conditions required for DRM lead to coking, metal aggregation. Although multiple mechanisms have been proposed, the molecular-level understanding of the reaction remains debated. Here, we report the synthesis of θ-Al2O3-supported Ni DRM catalysts via surface organometallic chemistry (SOMC) and report its outstanding activity and stability. The resulting Ni nanoparticles remain highly dispersed, with an average size of 5.3 ± 1.3 nm even after reduction at 900°C. This model catalyst exhibits distinct temperature-dependent behavior during DRM, with marked structural and mechanistic differences observed within a narrow 50°C range. In situ x-ray absorption spectroscopy (XAS) and ex situ synchrotron x-ray diffraction (XRD) reveal a dynamic induction process involving rapid Ni oxidation, followed by reduction and carbon insertion into the Ni lattice at 850°C, forming a carbide-like NiCx phase. At 800°C, incorporation of carbon is limited, thus leading to surface coking and catalyst deactivation. Furthermore, gas-switching experiments confirm the importance of a carbide cycle at 850°C, enabling continuous carbon removal and sustained catalytic stability.

The application of (W, Ti)C-Co cermet materials in harsh environments is constrained, necessitating further performance enhancement. In this study, (W, Ti)C-25 wt% Co samples with 0, 0.5, 1.0, 1.5, and 2 wt% hBN were fabricated via vacuum liquid-phase sintering. Phase evolution, grain boundary and phase interface characteristics and their correlation with properties were comprehensively analyzed via XRD, SEM, EDS, and EBSD. Results show that hBN addition induces the formation of a ternary W2Co21B6 phase. This new phase consumes W from (W, Ti)C and Co from the binder, which induces rightward shifts in (111) diffraction peaks of both phases. Microstructural analysis reveals transition of hard phase morphology toward equiaxed morphologies with reduced grain sizes, indicating grain growth inhibition effect of hBN. Crucially, hBN modifies grain boundary characteristics. With 1 wt% hBN addition, ultra-low-energy Sigma 3 boundaries partially convert to medium-energy Sigma 9 boundaries while preserving overall low-Sigma (3 <= Sigma <= 29) boundary density, enabling simultaneous enhancement of hardness (4.5 %) and fracture toughness (14.68 %). Larger addition of hBN promotes detrimental transformation of low-Sigma boundaries to high-energy random configurations, causing precipitous toughness decline (24.6 %) despite maximum hardness gain (8.91 %). Furthermore, hBN reduces friction coefficients effectively with abrasive wear as the main failure mechanism, though wear rate first increases then decreases due to the changes in the generation of W2Co21B6. Overall, hBN optimizes properties via phase evolution, grain boundary and phase interface modification.

Zeolite imidazolate frameworks (ZIFs)-derived carbon materials have garnered widespread attention as peroxymonosulfate (PMS) activators in removing antibiotics because of their excellent catalytic performance. However, most carbon materials derived from ZIFs exhibit limited efficacy in treating high-concentration (>10 ppm) antibiotic wastewater, and their synthesis methods are environmentally unfriendly. Herein, we develop a simple and environmentally friendly preparation method to synthesize a new type of nitrogen-doped carbon-supported carbon nanotubes coated with cobalt nanoparticle (Co-CNTs@NC) composites via high-temperature calcination of cobalt-zinc bimetallic ZIFs. The material characterization results confirm the successful preparation of Co-CNTs@NC composites featuring a high specific surface area (512.13 m(2)/g) and a Co content of 5.38 wt%. Across an initial pH range of 3.24-9.00, the Co-CNTs@NC/PMS catalytic system achieved over 84.17% degradation of 20 mg/L tetracycline hydrochloride within 90 min, demonstrating its favorable pH tolerance. The singlet oxygen-dominated degradation mechanism was confirmed by quenching experiments and electron paramagnetic resonance characterization. This work can provide technical guidance and reference significance for the preparation of metal-carbon materials derived from ZIFs with excellent efficiency of removal of high-concentration antibiotics.

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for visible-light-driven hydrogen evolution, yet its activity is limited by rapid charge recombination, low surface area, and insufficient light absorption. To overcome these bottlenecks, we designed and prepared an S-scheme g-C3N4 homojunction photocatalyst by compositing one-dimensional (1D) g-C3N4 nanotubes (TCN) with two-dimensional (2D) sulfur-doped g-C3N4 nanosheets (SCN). The optimized 1D/2D composite (TSCN-50) exhibits efficient interfacial charge transfer, as evidenced by XPS, and a prolonged fluorescence lifetime (8.73 ns) compared to SCN (3.94 ns) and TCN (4.80 ns), indicating suppressed carrier recombination. Under visible light irradiation, TSCN-50 exhibits an outstanding hydrogen evolution rate of 3025.7 & micro;mol g-1 h-1, which is 3.0 and 3.6 times higher than those of SCN and TCN, respectively, with excellent stability. Electron spin resonance (ESR) measurements further reveal a charge transfer pathway consistent with the S-scheme homojunction, which preserves and utilizes strongly reducing electrons. This work presents a novel non-metallic 1D/2D S-scheme homojunction strategy to boost the performance of g-C3N4-based photocatalysts.

Various supported metal catalysts have been developed to immobilize and stabilize metal species with small sizes and high dispersity. A hierarchical branch-like metal-organic frameworks (MOF) with nanosized branches and empty space between its building units facilitates the accession of substrates to metal active sites and the loading of nanoparticles, which make it an ideal carrier for developing supported metal nanocatalysts due to its high catalytic activity and load capacity. Herein, a Ag nanoparticle-loaded hierarchical CoZn-MOF (AgCZM) with enhanced peroxidase (POD)-like activity was prepared for the sensitive chemiluminescence (CL) assay. To prepare AgCZM, a pine-needle-cluster-like CoZn-MOF with POD-like activity was synthesized first via a one-pot solvothermal method. Then, the high-loaded CoZn-MOF-supported Ag nanoparticle catalyst for boosting its activity was synthesized by simply mixing CoZn-MOF and AgNO3 in polyvinylpyrrolidone (PVP) aqueous solution without using strong reducing agents, thereby enabling CoZn-MOF to retain its hierarchical structure. Further, the reactive oxygen species (ROS) generated during AgCZM-based and CoZn-MOF-based catalytic decomposition of H2O2 were verified and compared via scavenger experiments and electron paramagnetic resonance (EPR) tests, and the possible AgCZM-based luminol CL mechanism was explored. To validate the feasibility of the AgCZM-based CL assay, a CL system consisting of luminol, H2O2, and AgCZM was fabricated for dopamine (DA) detection with a negative response signal. The proposed AgCZM-based CL assay exhibited good linearities at low (5-125 nM) and high (0.625-1.75 mu M) DA concentrations with detection limits of 3.91 and 73.87 nM, respectively.

A novel thioether bond bridged triazine-based covalent organic framework (TTriC) was synthesized. TTriC exhibited a significant enhancement in tribological properties in PAO6, particularly in synergy with ZDDP. The TTriC/ZDDP composite demonstrated excellent tribological properties across various temperatures, load conditions, and test durations. It also improved extreme pressure performance to 1020N. This synergistic tribological mechanism may be attributed to the continuous adsorption of TTriC on the surface of the formed ZDDP friction film, providing a milder contact environment for the friction pairs. The interlayer sliding of TTriC reduced the loss of ZDDP friction film, thereby forming a stable chemically reactive film. This study provides a novel approach to the design of novel lubrication materials.

Effective charge separation and sufficiently exposed active sites are both critical limiting factors for solar-driven photocatalytic technology. In this paper, 2D oxygen-doped ultrathin porous g-C3N4 (UCN) and 2D ZnIn2S4 heterojunctions (UCN-ZIS) are formed by a high-temperature calcination-oil bath method. UCN with a highly ordered 2D heptazine structure within the layers has a suitable energy band structure, while the expansion of the interlayer spacing facilitates the acceleration of electron transfer for the construction of heterojunctions. During the in situ growth process, ZIS is uniformly distributed as ultrathin nanosheets on the high surface area of UCN. The optimised UCN-ZIS photocatalytic degradation of methyl orange reaches 99.4% efficiency (60 min), and the hydrogen precipitation activity reaches 1125.7 mu mol g-1 h-1, which is 4.61 times higher than that of pure ZIS, and this heterojunction possesses good photostability. This work contributes to the development of an efficient photocatalytic system with dual functions of hydrogen precipitation and organic pollutant degradation.

Due to isolated active sites of single-atom catalysts (SACs), the catalytic kinetics of SACs are often unsatisfactory in those catalytic reaction processes involving multiple intermediates and reaction pathways, such as the oxygen reduction reaction (ORR). To address this bottleneck and enhance the ORR performance of SACs, we developed a boron-doped Fe-Cu dual-atom catalyst (Fe-Cu-B/NC). This catalyst is designed to modulate the oxygen adsorption model and adjust the adsorption strength of oxygen intermediates at the metal sites. In situ synchrotron infrared spectroscopy demonstrated that the Fe-Cu-B/NC catalyst facilitates the adsorption of oxygen intermediates on the Fe-Cu dual sites through a bridge adsorption model, which is more favorable for O & horbar;O bond cleavage. Meanwhile, in situ electrochemical impedance spectroscopy revealed that the transformation of the adsorption model can accelerate the kinetics of intermediate species, further enhancing the catalytic efficiency. As a result, Fe-Cu-B/NC exhibits good ORR activity and strong durability, retaining 90% of its initial current density after 10 h of the ORR process in alkaline media.

Promotional effects are ubiquitous across catalytic processes involving supported nanoparticles, where additional elements, known as promoters, significantly enhance the catalytic performances (activity, selectivity, and/or stability) of nanoparticles. However, the inherent complexity of catalytic materials, comprising multiple species located both in the bulk and at the surface, makes it difficult to pinpoint the role of promoters at the molecular level. In this study, we disentangle the effect of alloying and interfacial sites in a low-temperature reverse water-gas shift (RWGS) reaction, a key process in the chemical industry, by precisely constructing catalysts featuring narrowly dispersed alloyed PtCr nanoparticles with or without Cr(III) interfacial sites. Notably, we show that a catalyst containing exclusively PtCr alloys, PtCr@SiO2, displays a substantial increase in catalytic activity compared to monometallic Pt@SiO2, while having additional Cr(III) interfacial sites (PtCr-Crint@SiO2) further improves the catalyst performance. In situ spectroscopic results reveal that the PtCr alloy facilitates a redox reaction pathway, whereas the presence of Cr(III) interfacial sites greatly facilitates CO2 adsorption and opens an additional formate-mediated pathway, further accelerating the reaction. These findings highlight the power of well-defined model systems in elucidating the promotional effects at the molecular level.

Removing high-concentration organic dye from wastewater is of great concern because the hazards can cause serious damage to the environment and human health. In this study, the hybrid dimensionally stable anode (DSA) with a Ce-doped and SnO2-Sb2O5 intermediate layer was fabricated and used for the electro-catalytic oxidation of three kinds of ultra-high-concentration organic dyes. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the denser surface structure and morphology of the composite Ti/SnO2-Sb2O5/Ce-PbO2 electrode. Moreover, the electrode exhibited an excellent oxygen evolution potential of 1.58 V. The effect on the removal efficiencies of high concentrations of up to 1 g/L of methyl orange, methylene blue, and neutral red solutions with the above composite electrode was investigated. The research results illustrated that target molecules in the three different dye solutions were rapidly decolorized and decomposed by electro-catalytic oxidation in less than 35 min. Additionally, the degradation process still followed pseudo-first-order kinetics for high-concentration dye solutions. The removal efficiency of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) for the three dye solutions was more than 98%, and the results of the gas chromatography–mass spectrometry (GC-MS) analysis showed that it had the best degradation effects for neutral red, which decomposed more thoroughly. More than 80 h of accelerated life also revealed excellent performance of the composite electrode in the face of high-concentration dye solution degradation. Considering these results, the Ti/SnO2-Sb2O5/Ce-PbO2 anode could be utilized to treat wastewater containing high-concentration dyes with high efficiency.

The Mg/Al hydrotalcite with different morphologies was prepared under mild conditions through a coprecipitation process. The sulfur- and phosphorus-free MA2 nanosheets were used in combination with MoDTC to improve the low load-bearing capacity and unsatisfactory tribological properties of organic molybdenum in PAO8. Especially, the 2.0 wt % MA2 nanosheets combined with 2.0 wt % MoDTC demonstrated the highest friction performances in PAO8. The results indicated that the synergistic effect between MA2 and MoDTC contributes to the formation of a stable tribofilm composed of MoS2, MgO, Al2O3, MoO3, Fe2(SO4)3, Fe2O3, and Fe3O4. This tribofilm not only could effectively protect the friction interface and provide friction-reducing and antiwear effects but also possess high film-forming rates (P B value) and load-bearing capacity.

Being a class of highly ordered porous materials, hydrogen-bonded organic frameworks (HOFs) hold great potential for developing promising enzyme mimics in sensing applications, yet remain underutilized in this field. Herein, a robust HOF@Co/Heme with stable peroxidase-like activity was synthesized by loading Heme and Co2+ to HOF for establishing a sensitive chemiluminescence (CL) assay of glucose. The scavenger experiment and electron paramagnetic resonance test revealed that reactive oxygen species (ROS) including 1O2, OH center dot and O2 center dot- were generated in HOF@Co/Heme-based catalytic decomposition of H2O2, and thereafter notably enhanced the CL signal of luminol-H2O2 CL system. Consequently, a CL biosensor based on glucose oxidase (GOx) and HOF@Co/Heme tandem catalysis was developed for sensitive detection of glucose, where GOx could catalyze glucose oxidation and offer H2O2 to HOF@Co/Heme for generating ROS and enhancing CL signal. Under optimized conditions, the GOx-HOF@Co/Heme-based biosensor exhibited a linear detection range from 0.06 to 6 mu M with an impressively low detection limit of 54 nM. Furthermore, its practicality was confirmed by the successful application in quantifying glucose in human serum samples.

Cutting fluids have long occupied an essential position in industrial manufacturing, but traditional mineral oil-based cutting fluids have limited their application in advanced manufacturing due to hazardous health, non-degradability, and poor thermal conductivity and cleaning ability. To this end, MXene (Ti3C2) was combined with oil-in-water (O/W) Pickering emulsion prepared from β-cyclodextrin-stabilized cottonseed oil to develop a new, highly efficient, environmentally friendly nano-cutting fluid. Among them, β-cyclodextrin, a cyclic oligosaccharide, can be employed as Pickering particles to improve the antioxidant and emulsion stability of cottonseed oil; MXene, an emerging class of 2D nanomaterials possessing excellent lubricating properties, mechanical properties, and thermal stability, is an ideal material for the preparation of high-performance nano-cutting fluids. Optimized by the response surface design, the prepared Pickering emulsion with MXene (0.1wt.%) remained stable for about a month without delamination and improved the thermal conductivity by 136.4% compared to cottonseed oil. Meanwhile, the coefficient of friction (COF), wear spot diameter (WSD), and tapping torque of Pickering emulsion with MXene were reduced by 35.64%, 10.90%, and 17.13%, respectively, compared with cottonseed oil, and also outperformed commercial cutting fluids. The reduction is attributed to the fact that the oxygen functional groups on the surface of MXene can form hydrogen bonds, which are adsorbed on the friction side to form a strong and dense lubricant film.

Cadmium sulfide (CdS), known for its strong light absorption capability and narrow band gap, has been extensively employed in photocatalytic degradation of organic pollution. However, when be exposed to light, the surface lattice sulfur of CdS undergoes rapid oxidation due to photo-generated holes, resulting in significant photocorrosion. Therefore, enhancing the stability and suppressing the photocorrosion of catalyst are crucial. In this study, Cd metal-loaded Cd-CdS@g-C3N4 composite catalysts are developed. This design not only effectively mitigates the issue of CdS photocorrosion but also exhibits outstanding photocatalytic degradation performance. XRD analysis reveals that Cd-CdS exhibits stronger diffraction peaks compared to CdS, indicating enhanced crystallinity and catalyst stability. Utilizing Cd as a metallic mediator, a rapid charge transfer across the heterojunctions is facilitated, bestowing the catalyst with superior photocatalytic efficiency. Notably, Cd-CdS exhibited the best photocatalytic degradation performance when the mass ratio of Cd-CdS to g-C3N4 was 1:2. The composite catalytic degradation efficiency of tetracycline hydrochloride (20g·L-1) by Cd-CdS@g-C3N4 after 20minutes reached 86.3%, and this commendable degradation rate was maintained even after four cycles. This research provides a vital approach towards enhancing the stability of g-C3N4/CdS heterojunction photocatalysts.

Single-atom (SA) Fe-N-C catalysts are considered as promising electrocatalysts for the oxygen reduction reaction (ORR). However, due to the drawbacks of the microporous structure and very strong binding with O intermediates, Fe-N-x active sites may not always display satisfactory catalytic performance. Therefore, simultaneously engineering hierarchical pores and introducing the second metal atom are promising strategies to break the bottleneck of SA Fe performance. Herein, an economical and environmentally friendly method is used to prepare an Fe-Co dual-atom catalyst (DAC) with a microporous/mesoporous coupled structure (HP/FeCo-NC-2). HP/FeCo-NC-2 effectively enhances the mass transfer process and the ORR activity of Fe-N-C. The atomic dispersion of the as-synthesized catalyst was confirmed by synchrotron X-ray absorption spectroscopy. The Brunauer-Emmett-Teller test was used to assess the number of catalyst-mesoporous structures, and HP/FeCo-NC-2 has a more mesoporous structure than HP/FeCo-NC-1. More mesopores allow faster electrolyte access to the active sites inside the catalyst, facilitating the rate of mass transfer during the reaction. Consequently, the structural advantages and interactions between Fe and Co endow HP/FeCo-NC-2 with ORR performance superior to those of HP/FeCo-NC-1 and HP/Fe-NC-2 in 0.1 M KOH.