3-mercaptopropyl Trimethoxysilane Research Articles

Thiol-Functionalized Cobalt Ferrite (CoFe2O4@MPTS) Nanoparticles as Cutting-Edge Adsorbents for Bovine Serum Albumin.

This paper describes the synthesis of CoFe₂O₄ nanoparticles via a simple ultrasonic-assisted co-precipitation method and their functionalization with thiol groups using (3-Mercaptopropyl)trimethoxysilane (MPTS) as the functionalizing agent. The use of ultrasonic energy not only serves as a green energy source but also reduces the reaction time fivefold compared to conventional methods. The synthesized CoFe₂O₄ nanoparticles were characterized for their surface and internal properties using instrumental techniques such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Vibrating Sample Magnetometer (VSM). The functionalized nanoparticles were applied for the effective adsorption of bovine serum albumin (BSA) from a buffered aqueous medium. To enhance the adsorption performance, the influence of pH, amount of solid adsorbent, initial BSA concentration, shaking time, and temperature on protein adsorption was investigated. Lagergren pseudo-second-order adsorption kinetics fitted the BSA adsorption data well, with an acceptable R² value of 0.976. Additionally, the BSA adsorption data were analyzed using Langmuir and Freundlich isotherm models, and it was concluded that the experimental data followed the Langmuir equation more closely than the Freundlich equation. At an initial pH of 5.57 (acetate buffer), the adsorption capacity (Q₀) for BSA protein was found to be 200mg/g. The thermodynamic study revealed ΔS° and ΔH° values of 17.40J/mol·K and - 45.37kJ/mol, respectively.

Gold Nanoparticle-Embedded Thiol-Functionalized Ti3C2Tx MXene for Sensitive Electrochemical Sensing of Ciprofloxacin.

The unregulated use of ciprofloxacin (CIPF) has led to increased resistance in patients and has threatened human health with issues such as digestive disorders, kidney disorders, and liver complications. In order to overcome these concerns, this work introduces a portable electrochemical sensor based on a disposable integrated screen-printed carbon electrode (SPCE) coated with gold nanoparticle-embedded thiol-functionalized Ti3C2Tx MXene (AuNPs-S-Ti3C2Tx MXene) for simple, rapid, precise, and sensitive quantification of CIPF in milk and water samples. The high surface area and electrical conductivity of AuNPs are maximized thanks to the strong interaction between AuNPs and SH-Ti3C2Tx MXene, which can prevent the aggregation of AuNPs and endow larger electroactive areas. Ti3C2Tx MXene was synthesized from Ti3AlC2 MAX phases, and its thiol functionalization was achieved using 3-mercaptopropyl trimethoxysilane. The prepared AuNPs-S-Ti3C2Tx MXene nanocomposite was characterized using FESEM, EDS, XRD, XPS, FTIR, and UV-visible spectroscopy. The electrochemical behavior of the nanocomposite was examined using CV, EIS, DPV, and LSV. The AuNPs-S-Ti3C2Tx MXene/SPCE showed higher electrochemical performances towards CIPF oxidation than a conventional AuNPs-Ti3C2Tx MXene/SPCE. Under the optimized DPV and LSV conditions, the developed nonenzymatic CIPF sensor displayed a wide range of detection concentrations from 0.50 to 143 μM (DPV) and from 0.99 to 206 μM (LSV) with low detection limits of 0.124 μM (DPV) and 0.171 μM (LSV), and high sensitivities of 0.0863 μA/μM (DPV) and 0.2182 μA/μM (LSV).

Development of mesoporous silica-based active coatings for methylmercury removal: Towards enhanced active packaging

Active coatings capable of selectively removing pollutants are an innovative approach against human exposure to pollutants via food. This study aimed to develop an active coating capable of removing methylmercury from liquid food media. Thiolation of mesoporous silica particles modified via (3-Mercaptopropyl)trimethoxysilane increased their mercury adsorption capacity to 100 mg/g. The particles were successfully integrated into industrial, epoxy and polyurethane coatings but the induced mercury adsorption efficiency in the coatings was dependent on their type of binder. Scanning electron microscopy and energy-dispersive X-ray results revealed that the silica particles were entrapped within the coatings but remained more accessible to the external media in the industrial and polyurethane coatings. Thermogravimetric analysis confirmed the successful integration of the components. The kinetics of adsorption showed that the adsorption of methylmercury was achieved within a time range of 20-240 min, depending on the binder used in the coating. The methylmercury adsorption ability of the coatings was preserved in different food simulants and in the presence of competitive ions and in an environment comprising cysteine. In vitro biosafety assays on different cell lines showed no negative effect from the silica modification on the safety of the coatings.

Improving Self-Healing Dental-Restorative Materials with Functionalized and Reinforced Microcapsules.

Dental resin composites are widely used in clinical settings but often face longevity issues due to the development and accumulation of microcracks, which eventually lead to larger cracks and restoration failure. The incorporation of microcapsules into these resins has been explored to introduce self-healing capability, potentially extending the lifespan of the restorations. This study aims to enhance the performance of self-healing dental resins by optimizing the microcapsules-resin matrix physicochemical interactions. Poly(urea-formaldehyde) (PUF) microcapsules were reinforced with melamine and subsequently subjected to surface functionalization with 3-aminopropyltriethoxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane (MPTMS). Additionally, microcapsules were functionalized with a bilayer approach, incorporating tetraethyl orthosilicate (TEOS) with either APTES or MPTMS. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) confirmed an increased Si:C ratio from 0.006 to 0.165. The functionalization process did not adversely affect the structure of the microcapsules or their healing agent volume. Compared to PUF controls, the functionalized microcapsules demonstrated enhanced healing efficiency, with TEOS/MPTMS-functionalized microcapsules showing the highest performance, showing a toughness recovery of up to 35%. This work introduces a novel approach to functionalization of microcapsules by employing advanced silanizing agents such as APTES and MPTMS, and pioneering bilayer functionalization protocols through their combination with TEOS.

Detection of Thiocholine for Pesticide Qualification Using Indium-Tin-Oxide-Coated Vertically Aligned Silicon Nanowires Extended Gate Field-Effect Transistor

Thiocholine is the hydrolysis of acetylthiocholine (ATCh) by acetylcholinesterase (AChE). The detection of thiocholine can be utilized to assess the activity and inhibitors of AChE, making it a valuable recognition element for constructing biosensors used in pesticide detection[1, 2]. The enzymatic hydrolysis of ATCh is catalyzed by AChE. First, high-aspect-ratio vertically aligned silicon nanowires (VASiNWs) were successfully fabricated through metal-assisted chemical etching (MACE). To investigate the impact of nanostructures on enhancing the sensitivity of the extended gate of the field-effect transistor (EGFET), the gate terminal was connected to 3-mercaptopropyl trimethoxysilane (MPTMS) modified indium-tin-oxide (ITO)-coated VASiNWs for the electrical detection of ATCh-catalyzed thiocholine, as illustrated in Figure 1. Various solutions of ATCh-catalyzed thiocholine were collected by applying different concentrations of ATCh (ranging from 2 mM to 10 mM) to the AChE-coated wells independently for 10 minutes. Subsequently, these solutions were introduced to the MPTMS modified ITO-coated VASiNWs EGFET, and the change in drain current was measured using a semiconductor parameter analyzer (HP 4145B). The thiocholine current demonstrated a sensitivity of 29.39 uA/concentration and a linearity of 0.88. Exploring the potential of pesticides to inhibit AChE hydrolysis represents a significant breakthrough, paving the way for the advancement of biosensors in pesticide detection. References Liu, G., et al., Sensitive electrochemical detection of enzymatically generated thiocholine at carbon nanotube modified glassy carbon electrode. Electrochemistry Communications, 2005. 7(11): p. 1163-1169. Pandey, P.C., et al., Acetylthiocholine/acetylcholine and thiocholine/choline electrochemical biosensors/sensors based on an organically modified sol–gel glass enzyme reactor and graphite paste electrode. Sensors and Actuators B: Chemical, 2000. 62(2): p. 109-116. Figure 1

Green ammonia production via recycle membrane reactor: Experiment and process simulation

With the increasing demand for ammonia (NH3) and the environmental benefits, green and sustainable NH3 production has been urgently developed and is expected to replace the traditional Haber-Bosch (HB) process with high energy consumption and COx emission. In this work, a recycle membrane reactor (RMR) process where a catalytic reactor relates to a membrane separator in series and the retentate stream is recycled to the reactor was designed and executed to produce NH3, in which a Ru (10 wt%)/Cs/MgO catalyst and two membranes with different permeation properties and NH3 selectivity were used. By independently controlling the temperature of the reactor and membrane separator, the synthesized NH3 was selectively extracted from feed side to permeate side by Aquivion/ceramic composite and sulfonated (3-mercaptopropyl)trimethoxysilane membranes. Impressively, NH3 mole fraction was greatly increased from 0.01 of equilibrium state to 0.1–0.45 in permeate stream, which is ascribed to the permeation properties and NH3 selectivity of membrane at different temperatures. Moreover, a one-dimensional, isothermal, and plug-flow model was proposed to simulate RMR, which can be successfully applied to deeply understand the mechanism of RMR. Furthermore, a green NH3 production process based on RMR was simulated to give rationalized suggestions for the NH3 synthesis under mild conditions.

Selective Capturing of the CO2 Emissions Utilizing Ecological (3-Mercaptopropyl)trimethoxysilane-Coated Porous Organic Polymers in Composite Materials.

Capturing carbon dioxide (CO2) is still a major obstacle in the fight against climate change and the reduction of greenhouse gas emissions. To address this problem, we employed a simple Friedel-Crafts alkylation to investigate the effectiveness of porous organic polymers (POPs) based on triphenylamine (TPA) and trihydroxy aryl terms derived from chloranil (CH), designated as TPA-CH POP. We then treated the TPA-CH POP with (3-mercaptopropyl)trimethoxysilane (3-MPTS), forming a TPA-CH POP-SH nanocomposite to enhance CO2 capture. Utilizing FTIR, solid-state NMR, SEM, TEM, along with XPS techniques, the molecular makeup, morphological characteristics, as well as physical features of TPA-CH POP and the TPA-CH POP-SH nanocomposite were thoroughly explored. Upon scorching to 800 °C, the TPA-CH POP-SH nanocomposite demonstrated more thermal durability over TPA-CH POP, achieving a char yield of up to 71.5 wt.%. The TPA-CH POP-SH nanocomposite displayed a 2.5-times better CO2 capture, as well as a comparable adsorption capacity of 48.07 cm3 g-1 at 273 K. Additionally, we found that the TPA-CH POP-SH nanocomposite exhibited an improved CO2/nitrogen (N2) selectivity versus the original TPA-CH POP. Typical enthalpy changes for CO2 capture were somewhat increased by the 3-MPTS coating, indicating greater binding energies between CO2 molecules and the adsorbent surface. Our outcomes demonstrate that a TPA-CH POP composite coated with MPTS is a viable candidate for effective CO2 capture uses. Our findings encourage the investigation of different functional groups and optimization strategies.

Solvent-free thiol-Ene/-Yne click reactions for the synthesis of alkoxysilyl telechelic poly(propylene oxide)s

Thiol-ene/−yne click reactions can be a versatile toolbox for the design and modification of polymers, enhancing functionality and providing opportunities for the development of innovative materials and applications. Here, we report a simple strategy to synthesize alkoxysilyl telechelic poly(propylene oxide)s (PPO)s: a) through a post-polymerization functionalization via Williamson reactions, commercial PPO is modified at the chain-end secondary alcohols with allyl or propargyl units, achieving >99% conversion; b) subsequent click reactions of (3-mercaptopropyl)trimethoxysilane (MPTMS), triggered by thermal and photochemical radical initiators, result in the incorporation of alkoxysilane groups on the polyether chain. Both thermal and photochemical thiol-ene/−yne click pathways are robust methodologies for preparing alkoxysilyl-modified PPOs in excellent yields (> 99%). Optimal conditions were identified as solvent-free, at 65 °C with 2,2′-azobis(2-methylpropionitrile) (AIBN) as the radical source. Detailed NMR analyses confirm the quantitative transformation of vinyl/propargyl functionalities in the resulting alkoxysilyl telechelic PPOs. Preliminary studies on the stability of alkoxysilyl end-groups are reported using 29Si NMR spectroscopy.

Enhancing the Thermal Resistance of UV-Curable Resin Using (3-Thiopropyl)polysilsesquioxane.

This study delineates a methodology for the preparation of new composites based on a photocurable urethane-acrylate resin, which has been modified with (3-thiopropyl)polysilsesquioxane (SSQ-SH). The organosilicon compound combines fully enclosed cage structures and incompletely condensed silanols (a mixture of random structures) obtained through the hydrolytic condensation of (3-mercaptopropyl)trimethoxysilane. This process involves a thiol-ene "click" reaction between SSQ-SH and a commercially available resin (Ebecryl 1271®) in the presence of the photoinitiator DMPA, resulting in composites with significantly changed thermal properties. Various tests were conducted, including thermogravimetric analysis (TGA), Fourier transmittance infrared spectroscopy (FT-IR), differential scanning calorimetry (Photo-DSC), and photoreological measurement mechanical property, and water contact angle (WCA) tests. The modification of resin with SSQ-SH increased the temperature of 1% and 5% mass loss compared to the reference (for 50 wt% SSQ-SH, T5% was 310.8 °C, an increase of 20.4 °C). A composition containing 50 wt% of SSQ-SH crosslinked faster than the reference resin, a phenomenon confirmed by photorheological tests. This research highlights the potential of new composite materials in coating applications across diverse industries. The modification of resin with SSQ-SH not only enhances thermal properties but also introduces a host of functional improvements, thereby elevating the performance of the resulting coatings.

Switchable metal extractant integrated miniaturized 3D-printed device: A semi-online multi-metal separation system for matrix-free ICP-MS analysis

BackgroundThis study tackles the critical challenges in metal analysis by presenting an innovative miniaturized metal extraction device prototype. This device features a functional nanocomposite (FNC) enhanced 3D-printed polylactic acid (PLA) metal extractant (FNC@3D PLA). The research is motivated by the constraints of traditional solid-phase extraction (SPE) methods, specifically their limitations in handling competitive metal ion environments and matrix interference during inductively coupled plasma mass spectrometry (ICP-MS) analysis. The designed prototype aims to overcome these challenges and enhance the extraction efficiency of diverse metals. ResultsThe FNC, designed to incorporate various functional groups critical for metal ion extraction efficiency, was meticulously engineered through the reaction of acid-treated and delaminated graphitic carbon nitride nanosheets (Thiol-gCN NSs) with 3-mercaptopropyl trimethoxysilane (MPTMS). The competitive metal ion extraction efficiency of FNC@3D PLA was demonstrated, showcasing notable limit of detection values of 3.2 ± 0.7 ng mL−1 and 8.57 ± 3.05 ng mL−1 for Cu and Ag, respectively. Furthermore, the miniaturized 3D-printed metal-preconcentration setup incorporating FNC@3D PLA exhibited favorable intraday relative standard deviation (RSD) percentage (%) values ranging from 1.23 to 8.6 for both Cu and Ag. Interday RSD % between 1.41 and 8.14 were observed under spiked real urine sample conditions. The sustainability and robustness of the proposed approach were underscored by substantial recovery % values exhibited by FNC@3D PLA, even after eight consecutive regeneration processes. SignificanceThis study significantly contributes to the advancement of analytical methodologies by providing a reliable and efficient platform for metal extraction and preconcentration in practical metal analysis applications. Developed FNC@3D PLA system demonstrates its potential to address the challenges associated with SPE in metal analysis, especially in complex sample matrices. We believe implications of this research can be extended to various fields, from environmental monitoring to clinical diagnostics, where accurate and reliable metal analysis is paramount.

Fabrication of 3-(trihydroxysilyl)-1-propanesulfonic acid membranes with superior affinity and selectivity for NH3 permeation over H2 and N2 at 50–300 °C

Ammonia (NH3) produced by Haber-Bosch process is separated through the condensation process, which needs a large amount of energy consumption. Membrane separation technology is compelling for achieving energy-saving and efficient NH3 separation. Therefore, 3-(trihydroxysilyl)-1-propanesulfonic acid (TPS) was applied, for the first time, to fabricate sulfonic silica-based membranes and evaluated for NH3 selective permeation. The amorphous siloxane network can be formed by simple condensation of silanol (Si–OH) under sulfonic acid (-SO3H) self-catalysis, as confirmed by the results of Fourier transform infrared spectroscopy and X-Ray diffractometry. Moreover, TPS xerogel powders dried from TPS sols showed excellent thermal stability and dense structure via thermogravimetric and N2 adsorption analyses. Importantly, an intensive NH3 adsorption amount of ∼3.0 mmol g−1 for TPS xerogels from NH3 adsorption and temperature-programmed desorption was twice higher than the reported oxidized (3-mercaptopropyl)trimethoxysilane xerogels (∼1.41 mmol g−1), which was ascribed to the inherently stronger proton-acidic -SO3H groups in TPS. Finally, TPS membranes prepared using TPS solutions diluted with ethanol expressed superior NH3-selective permeation based on favorable molecular sieving and NH3 adsorption-diffusion via single and binary gas permeation, especially remarkable NH3 permeance of ∼2.6 × 10−7 mol m−2 s−1 Pa−1 and excellent NH3/N2 selectivity of 266 at 300 °C.

Extremely Stable Ag-Based Photonics, Plasmonic, Optical, and Electronic Materials and Devices Designed with Surface Chemistry Engineering for Anti-Tarnish.

Silver (Ag) metal-based structures are promising building blocks for next-generation photonics and electronics owing to their unique characteristics, such as high reflectivity, surface plasmonic resonance effects, high electrical conductivity, and tunable electron transport mechanisms. However, Ag structures exhibit poor sustainability in terms of device performance because harsh chemicals, particularly S2- ions present in the air, can damage their structures, lowering their optical and electrical properties. Here, the surface chemistry of Ag structures with (3-mercaptopropyl)trimethoxysilane (MPTS) ligands at room temperature and under ambient conditions is engineered to prevent deterioration of their optical and electrical properties owing to S2- exposure. Regardless of the dimensions of the Ag structures, the MPTS ligands can be applied to each dimension (0D, 1D, and 3D). Consequently, highly sustainable plasmonic effects (Δλ < 2nm), Fabry-Perot cavity resonance structures (Δλ < 2nm), reflectors (ΔRReflectance < 0.5%), flexible electrodes (ΔRelectrical < 0.1 Ω), and strain gauge sensors (ΔGF < 1), even in S2- exposing conditions is achieved. This strategy is believed to significantly contribute to environmental pollution reduction by decreasing the volume of electronic waste.

XPS and ARXPS for Characterizing Multilayers of Silanes on Gold Surfaces

X-ray photoelectron spectroscopy (XPS) and angle-resolved XPS (ARXPS) characterization of surface layers resulting from the functionalization of polymers such as polyvinylchloride (PVC) modified with 3(mercaptopropyl)-trimethoxysilane (MPTMS) and (3-aminopropyl) triethoxysilane (APTES) is challenging due to the overlap in signals, deriving both from the substrate and the functionalized layers. In this work, a freshly cleaved, ideally flat gold surface was used as carbon-free model substrate functionalized with MPTMS and subsequently grafted with APTES. Avoiding the overlap of signals from carbon atoms present in the substrate, the signals in the C1s, O1s, Si2p, S2p and N1s high-resolution spectra could be assigned to the MPTMS/APTES functionalized layer only and the curve-fitting parameters could be determined. Quantitative analysis was in very good agreement with the expected stoichiometry of the functionalized layer, confirming the adopted curve-fitting procedure. In addition, it was found that one molecule of APTES grafted two MPTMS via silane groups. ARXPS allowed for determining the thickness of the functionalized layers: MPTMS thickness was found to be 0.5 (0.2) nm, whereas MPTMS + APTES thickness 1.0 (0.2) nm was in good agreement with Avogadro model calculations. This approach can be considered a powerful tool for characterizing functionalized surfaces of more complex systems by XPS.

Enhancing Stability and Efficiency of Inverted Inorganic Perovskite Solar Cells with In-Situ Interfacial Cross-Linked Modifier.

Inverted inorganic perovskite solar cells (PSCs) is potential as the top cells in tandem configurations, owing to the ideal bandgap, good thermal and light stability of inorganic perovskites. However, challenges such as mismatch of energy levels between charge transport layer and perovskite, significant non-radiative recombination caused by surface defects, and poor water stability have led to the urgent need for further improvement in the performance of inverted inorganic PSCs. Herein, the fabrication of efficient and stable CsPbI3-x Brx PSCs through surface treatment of (3-mercaptopropyl) trimethoxysilane (MPTS), is reported. The silane groups in MPTS can in situ crosslink in the presence of moisture to build a 3-dimensional (3D) network by Si-O-Si bonds, which forms a hydrophobic layer on perovskite surface to inhibit water invasion. Additionally, -SH can strongly interact with the undercoordinated Pb2+ at the perovskite surface, effectively minimizing interfacial charge recombination. Consequently, the efficiency of the inverted inorganic PSCs improves dramatically from 19.0% to 21.0% under 100mW cm-2 illumination with MPTS treatment. Remarkably, perovskite films with crosslinked MPTS exhibit superior stability when soaking in water. The optimized PSC maintains 91% of its initial efficiency after aging 1000 h in ambient atmosphere, and 86% in 800 h of operational stability testing.

Fabrication of a robust zwitterionic coating on glass with anti-fogging, anti-frosting, self-cleaning and antibacterial properties via UV-induced grafting polymerization

In this work, glass slides were separately silanized by silane coupling agents, 3-(trimethoxysilyl) propyl methacrylate (TPM) and 3-(mercaptopropyl) trimethoxysilane (MPS). Then, in presence of a photoinitiator, multifunctional hydrophilic coatings were fabricated facilely on these silanized glasses via UV-induced grafting polymerization of zwitterionic acrylic monomer methacryloxyethyl sulfobetaine (SBMA). The results showed that both TPM and MPS silanized glasses could participate in the UV-induced grafting polymerization of SBMA, while more SBMA could be grafted to the former glass to gain a little bit higher hydrophilicity. The structure, morphology and properties of the multifunctional glasses were investigated fully. As the hydrophilic polymer brushes poly(SBMA) (pSBMA) covalently attached to the glass surface, the glasses could render a series of excellent performances, including underwater superoleophobicity, anti-fogging, anti-frosting, abrasion resistance, self-cleaning and antibacterial adhesion, and especially high stability even after being immersed in water for 20 days. The strong interaction of pSBMA and water was confirmed via differential scanning calorimeter (DSC) and Raman spectrum analysis, to explicit the anti-fogging mechanism. Therefore, it is promising that the scalable multifunctional glass fabricated via UV-induced grafting polymerization could be potentially applied in the fields of automobile, bathroom, medical, etc.

Mechanically robust multifunctional starch films reinforced by surface-tailored nanofibrillated cellulose

The objective of this study was to develop a transparent, mechanically robust, and fully biodegradable film made of sweet potato starch (SPS) reinforced with nanofibrillated cellulose (NFC) to serve as a potential alternative for packaging. Various surface modifications were applied to NFC using urea/NaOH (UA), oxalic acid (OA), citric acid (CA), and (3-mercaptopropyl) trimethoxysilane (MT). SPS/NFC blend was innovatively treated by ball-milling, incorporating different concentrations (2–10 wt%) of surface-modified NFC and calcium gluconate as a modifier. Interestingly, the solution-cast blend films possessed improved tensile strength, tensile modulus, crystallinity, barrier property and hydrophobicity after NFC additions. More importantly, ball-milling promoted the physical combination of starch and NFC and generated metal-organic supramolecular interaction between –OH and Ca2+. In particular, the SPS-OA/NFC6 composite film exhibited remarkable improvements in tensile strength and tensile modulus, increasing from 1.46 MPa to 13.7 MPa and 6.04 MPato 531.33 MPa, respectively, compared to the neat SPS film. The contact angle of the SPS/CA-NFC6 film was approximately 79% higher than that of the pure SPS film. Generally, the optimal NFC addition was 6 wt%. This study provides guidance for the production of a new type of starch-based material with high mechanical strength and transparency.

Development of sulfonated (3-Mercaptopropyl)trimethoxysilane membranes with thermal stability and excellent NH3 perm-selectivity at 300 °C

(3-Mercaptopropyl)trimethoxysilane (MPTMS) sols, xerogels, and membranes with and without H2O2 oxidation were prepared to improve NH3 affinity and selectivity particularly at high temperatures. Mercaptan (S–H) in MPTMS precursor can be completely oxidized to transform SO originated from various sulfur oxidization groups by mixing H2O2 to sol solution for enhancing NH3 affinity, as proven by FT-IR and XPS analyses. Thermogravimetric mass spectrometer (TG-MS) and N2 adsorption respectively verified the thermal stability and the dense structure of unoxidized and oxidized MPTMS xerogels around 300 °C. Furthermore, NH3 temperature-programmed desorption (NH3-TPD) revealed that oxidized MPTMS xerogels showed a strong NH3 affinity (NH3 adsorption amount of ∼1.41 mmol g−1), twice higher than that of unoxidized MPTMS xerogels (0.75 mmol g−1) owing to the strengthened acidity and increased acidic sites. Finally, oxidized MPTMS membranes expressed an excellent selectivity for NH3/H2 of 6 and NH3/N2 of 18 with an NH3 permeance of ∼1.4 × 10−7 mol m−2 s−1 Pa−1 at 300 °C for single gas permeation. NH3 permeance and selectivity at 300 °C in NH3/H2 and NH3/N2 mixed gas permeation were almost constant without any mixing-effects, consistent with those in single gas permeation.

Robust Gold Electrode Fabrication in a Microfluidic System

Electrode fabrication in microfluidic devices is often avoided due to the smaller footprint of the platform, associated complexity in the process, and absence of a well-established method. In this article a glass microchip with chemically modified and vapor deposited gold internal electrode was fabricated and used for biomolecule immobilization and electrochemical applications. The silanol (-OH) on glass surface of the microdevice was modified with (3-mercaptopropyl)trimethoxysilane prior to gold deposition to achieve a strong attachment of the metal film using the gold-thiol binding. The practical utility of the microdevice with gold surface was demonstrated by performing quantitative enzyme linked immunosorbent assay (ELISA) of human interferon gamma (IFN-γ) antigen, yielding a limit of detection (LOD) of 0.15 pg/mL compared to 4 pg/mL in the microplate assay. Additionally, the functionality of the internal electrode was established by performing cyclic voltammetry (CV) and linear sweep voltammetry (LSV) of potassium ferricyanide (III) in potassium chloride (KCl) solution using the proposed gold patterned electrode in the microchip, offering limits of detection of 0.14 and 0.11 mM for CV and LSV respectively. Both the ELISA and electrochemical assays were validated by generating calibration curves and using a control sample for the electroanalytical sensing applications. The measurements yielded experimental results that agreed with control concentration with 7% relative standard deviation (RSD). The promising reproducibility of the electrode in fabrication with no/minimum failure rate and its outstanding performance in immunosensor applications as well as an electron exchange surface makes our technique of gold electrode fabrication in microchips a state of the art.

Kaolin-based metal-organic frameworks for sustainable natural gas storage

Natural gas (NG) is increasingly regarded as one of the most environmentally friendly forms of energy. However, low volumetric density, high leakage rate and explosion during transportation and storage limit the accessibility and consumption of NG. To bridge the gap, this work reports on the formulation of metal-organic frameworks (MOFs) for onboard storage of natural gas using kaolin clay, chitosan, dimethyl sulfoxide, potassium acetate and (3-mercaptopropyl) trimethoxysilane. Results of formulated MOFs (CKO, PKT, DKT, DKO, and PKO) from the thermogravimetric analysis showed that the thermal stability ranged from 226 to 550 °C implying that the MOFs at this temperature range can maintain their structural integrity and resist decomposition throughout the adsorption process. The results of Porosimetry indicated that the synthesized MOFs exhibit a surface area within the range of 195.239–611.802 cm2/g and a pore volume ranging from 0.412 to 0.967 cm3/g. These findings suggest that the prepared MOFs possess a practical adsorption capacity for natural gas. Adsorption tests demonstrated that CKO and PKT MOFs exhibited higher natural gas (NG) adsorption capacities (0.028 and 0.017 g/g) over DKT, DKO, and PKO (0.014 g/g, 0.0095 g/g, and 0.0083 g/g) at 5 bar. These results underscore the increased capacity of MOFs to store significant quantities of natural gas under low-pressure conditions compared to previous literature. Conversely, the strong correlation coefficients (R > 0.95) observed in the adsorption isotherms of the developed MOFs provide confirmation that natural gas adsorption took place on uniform adsorption sites, aligning with the Langmuir adsorption isotherm. Overall, the findings of this study demonstrated the potential of kaolin-based metal-organic frameworks for use in the energy sector and expanded the search for sustainable onboard natural gas storage solutions.

Au9 nanocluster adsorption and agglomeration control through sulfur modification of mesoporous TiO2.

In the present work phenyl phosphine-protected Au9 nanoclusters were deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS) modified and unmodified mesoporous screen printed TiO2. The removal of the cluster ligands by annealing was applied to enhance the interaction between Au cluster cores and semiconductor surfaces in the creation of efficient photocatalytic systems. The heat treatment could lead to undesired agglomeration of Au clusters, affecting their unique properties as size specific clusters. To address this challenge, the semiconductor surfaces were modified by MPTMS. Characterization techniques confirm the effectiveness of the modification processes, and XPS demonstrates that S functionalized MTiO2 is more efficient than MTiO2 in increasing Au9 NCs adsorption by a factor of 10 and preventing Au cluster agglomeration even after annealing. Overall, this work contributes valuable insights into photocatalytic systems through controlled modification of semiconductor surfaces and Au nanocluster deposition.