Surface Functionalization Methods Research Articles

Effect of surface functionalization on the quantum capacitance of M2CF2 (M = Ti, V, Cr, Zr, Nb, Mo) as supercapacitor electrodes

The surface charge storage capacity, atomic structures, and quantum capacitance of M2CF2 (M=Ti, V, Cr, Zr, Nb, Mo) are investigated using density functional theory (DFT). The influence of different surface functionalization methods on the capacitance performance of M2CF2 is also examined, including the introduction of vacancy defects (C-, F-, M-vacancy) and nonmetal doping (N, O, and S). The findings show that both defects and doping reduce the quantum capacitance of V2CF2, Cr2CF2, and Mo2CF2, but they have a negligible impact on the capacitance behavior of Ti2CF2, Zr2CF2 and Nb2CF2. Furthermore, the pristine Cr2CF2 system exhibits relatively high quantum capacitance and surface charge storage capacity under both positive and negative bias. However, the presence of vacancies and dopants significantly decreases its capacitance. Among the structures studied, pristine and nonmetal-doped V2CF2 demonstrate the highest quantum capacitance values (1302.02–1517.56 μF/cm2), suggesting its potential as an effective positive electrode material. Overall, the findings of this study are expected to boost the development of high-capacitance electrodes in the future.

Microfluidics Evolution and Surface Functionalization: A Pathway to Enhanced Heavy Metal Ion Detection

AbstractThis review delves into the significant advancements in microfluidic technology since 2017, highlighting its critical role in shrinking device sizes and integrating advanced surface functionalization techniques. It showcases how microfluidics, an interdisciplinary field, has revolutionized fluid manipulation on a microscale, enabling the creation of cost‐effective, portable devices for on‐the‐spot analyses, like heavy metal ion detection. From its early days rooted in ancient observations to cutting‐edge uses of materials like silicon, glass, polydimethylsiloxane (PDMS), and paper, this review charts microfluidics’ dynamic evolution. It emphasizes the transformative impact of surface functionalization methods, including silanization and plasma treatments, in enhancing device materials' performance. Moreover, this review anticipates the exciting convergence of microfluidics with emerging technologies like droplet microfluidics and three‐dimensional (3D) printing, alongside nanotechnology, forecasting a future of sophisticated analytical tools, point‐of‐care diagnostics, and improved detection systems. It acknowledges the hurdles in scaling production and achieving universal reliability and standardization. This review highlights the transformative impact of microfluidic technology on diagnostics and environmental surveillance, emphasizing its utility in deploying compact sensors for comprehensive and concurrent evaluations of water quality.

Grafting Block Copolymer Nanoparticles to a Surface via Aqueous Photoinduced Polymerization-induced Self-Assembly at Room Temperature.

The creation of well-defined surface nanostructures is important for a diverse set of applications such as cell adhesion, superhydrophobic coating, and lithography. In this study, we describe a robust bottom-up method for surface functionalization that involves surface-initiated reversible deactivation radical polymerization (RDRP) and the grafting of block copolymer nanoparticles to material surfaces via aqueous photoinduced polymerization-induced self-assembly (photo-PISA) at room temperature. Using silica nanoparticles as a model substrate, colloidal mesoscale hybrid assemblies with various morphologies were successfully prepared. The morphologies can be easily tuned by changing the lengths of macromolecular chain transfer agents and parameters of the silica nanoparticles. The surface-initiated photo-PISA approach can also be employed for other large-scale substrates such as silicon wafer. Taking advantage of mild reaction conditions of this method (room temperature, aqueous medium, and visible light), enzymatic deoxygenation was introduced to develop oxygen-tolerant surface-initiated photo-PISA that can fabricate well-defined nanostructures on large-scale substrates under open-to-air conditions.

Boronic acid conjugated polyacrylate coating: A strategy for material-independent surface functionalization

Most biomaterial surfaces are non-functional, which inevitably requires additional functionalization steps. However, these steps are typically material-dependent; only a few limited methods, such as catechol functionalization using polydopamine coating, have been reported as material-independent for surface modification. In this study, we developed a one-step boronic acid surface functionalization method utilizing a polyacrylate that contains both butyl and boronic acid groups. The butyl group exhibits strong interfacial adhesion due to its low glass transition temperature (Tg), which maintains its softness and tackiness, thereby facilitating attachment to various substrates. Meanwhile, the boronic acid acts as a functional group for surface modification. Various substrates, including polymers, metals, and ceramics widely used in implants, were successfully coated with the polyacrylate, bestowing boronic acid functionality on the surface. Given that boronic acid is one of the most widely applied functional groups in the biomaterials field, we anticipate that our methodology will be applicable in developing various biomedical applications such as antifouling coatings, biosensors, and bioadhesives.

Nanopatterned Monolayers of Bioinspired, Sequence-Defined Polypeptoid Brushes for Semiconductor/Bio Interfaces.

The ability to control and manipulate semiconductor/bio interfaces is essential to enable biological nanofabrication pathways and bioelectronic devices. Traditional surface functionalization methods, such as self-assembled monolayers (SAMs), provide limited customization for these interfaces. Polymer brushes offer a wider range of chemistries, but choices that maintain compatibility with both lithographic patterning and biological systems are scarce. Here, we developed a class of bioinspired, sequence-defined polymers, i.e., polypeptoids, as tailored polymer brushes for surface modification of semiconductor substrates. Polypeptoids featuring a terminal hydroxyl (-OH) group are designed and synthesized for efficient melt grafting onto the native oxide layer of Si substrates, forming ultrathin (∼1 nm) monolayers. By programming monomer chemistry, our polypeptoid brush platform offers versatile surface modification, including adjustments to surface energy, passivation, preferential biomolecule attachment, and specific biomolecule binding. Importantly, the polypeptoid brush monolayers remain compatible with electron-beam lithographic patterning and retain their chemical characteristics even under harsh lithographic conditions. Electron-beam lithography is used over polypeptoid brushes to generate highly precise, binary nanoscale patterns with localized functionality for the selective immobilization (or passivation) of biomacromolecules, such as DNA origami or streptavidin, onto addressable arrays. This surface modification strategy with bioinspired, sequence-defined polypeptoid brushes enables monomer-level control over surface properties with a large parameter space of monomer chemistry and sequence and therefore is a highly versatile platform to precisely engineer semiconductor/bio interfaces for bioelectronics applications.

Catalyst-Free Amino-Yne Click Reaction: An Efficient Way for Immobilizing Amoxicillin onto Polymeric Surfaces.

Surface modifications play a crucial role in enhancing the functionality of biomaterials. Different approaches can be followed in order to achieve the bioconjugation of drugs and biological compounds onto polymer surfaces. In this study, we focused on the immobilization of an amoxicillin antibiotic onto the surface of poly-L-lactic acid (PLLA) using a copper-free amino-yne click reaction. The utilization of this reaction allowed for a selective and efficient bioconjugation of the amoxicillin moiety onto the PLLA surface, avoiding copper-related concerns and ensuring biocompatibility. The process involved sequential steps that included surface activation via alkaline hydrolysis followed by an amidation reaction with ethylendiamine, functionalization with propiolic groups, and subsequent conjugation with amoxicillin via a click chemistry approach. Previous amoxicillin immobilization using tryptophan and fluorescent amino acid conjugation was carried out in order to determine the efficacy of the proposed methodology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), Attenuated Total Reflection (ATR)-Fourier Transform Infrared (FTIR) spectroscopy, surface imaging, water contact angle determination, and spectroscopic analysis confirmed the successful immobilization of both tryptophan and amoxicillin while maintaining the integrity of the PLLA surface. This tailored modification not only exhibited a novel method for surface functionalization but also opens avenues for developing antimicrobial biomaterials with improved drug-loading capacity.

Two decades of ceria nanoparticle research: structure, properties and emerging applications.

Cerium oxide nanoparticles (CeNPs) are versatile materials with unique and unusual properties that vary depending on their surface chemistry, size, shape, coating, oxidation states, crystallinity, dopant, and structural and surface defects. This review encompasses advances made over the past twenty years in the development of CeNPs and ceria-based nanostructures, the structural determinants affecting their activity, and translation of these distinct features into applications. The two oxidation states of nanosized CeNPs (Ce3+/Ce4+) coexisting at the nanoscale level facilitate the formation of oxygen vacancies and defect states, which confer extremely high reactivity and oxygen buffering capacity and the ability to act as catalysts for oxidation and reduction reactions. However, the method of synthesis, surface functionalization, surface coating and defects are important factors in determining their properties. This review highlights key properties of CeNPs, their synthesis, interactions, and reaction pathways and provides examples of emerging applications. Due to their unique properties, CeNPs have become quintessential candidates for catalysis, chemical mechanical planarization (CMP), sensing, biomedical applications, and environmental remediation, with tremendous potential to create novel products and translational innovations in a wide range of industries. This review highlights the timely relevance and the transformative potential of these materials in addressing societal challenges and driving technological advancements across these fields.

MODIFIED MAGNETITE NANOPARTICLES WITH THE JUICE OF PLANTAIN PSEUDOSTEM: AN OPTION FOR WATER DECONTAMINATION

In recent years, various methods for surface functionalization of magnetite nanoparticles with emerging modifications have been explored and reported. Green nano-chemistry aims to synthesize nanomaterials using bio-based resources, providing new materials for biological and environmental applications. Surface modification of magnetite nanoparticles using phytochemicals extracted from plants is a fundamental principle of green synthesis routes. Agricultural waste from different crops, such as plantain pseudostem, is of particular interest as a renewable resource due to its abundant availability, low toxicity, and economic feasibility. In this study, the juice extracted from plantain pseudostem was utilized for the phytofunctionalization of magnetite nanoparticles. Characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and fourier-transform infrared spectroscopy (FTIR) confirmed the nanometric dimensions of the composite (size range of 12.6 ± 3.17 nm) and established its organic-inorganic nature. The superparamagnetic properties of the composite were also demonstrated. Moreover, the potential application of this nanohybrid in bioremediation for the immobilization of cadmium(II) and lead(II) showed promising results, highlighting its efficacy in managing water pollutants.

Surface Functionalized Mesoporous Silica Nanoparticles for Enhanced Removal of Heavy Metals: A Review

Human health and environmental sustainability are strongly influenced by the contamination of water resources with hazardous heavy metal ions due to the accumulation in human body via food chains. Thereby, researchers’ attention has been paid on effective methods for heavy metal ion scavenging to prevent them releasing to environment. Notably, Mesoporous Silica Nanoparticles (MSNPs) with high surface area, massive surface area to volume ratio, large pore volume and uniform pore distribution play a crucial role in addressing this challenge. Additionally, researchers focus on novel surface functionalization methods of MSNPs with suitable organic and inorganic moieties to amplify the adsorption efficiency of heavy metals. MSNPs possess easily functionalizable surface which facilitates the modifications and enhanced removal of heavy metals. The review article summarizes the different moieties used for functionalization of MSNPs such as amino, thio, carboxyl, phenyl, cyano groups, different types of polymers, inorganic functional groups. Further, a comparison has been made between functional and unmodified MSNPs to elaborate how these modifications have enhanced the removal performance of heavy metals in water. Further, this review provides an overview on different synthesis routes and structure directing agent used in synthesis of MSNPs. Moreover, pH effect on adsorption andreusability of modified NPs, while illustrating the mechanism of adsorption on to modified MSNPs surface has also been elaborated. Maximum adsorption capacity of each functional moiety has been taken into consideration with the aim of supporting future advancements.
 Keywords: Adsorption, Mesoporous silica nanoparticles, Heavy metals, Functionalization, Maximum adsorption capacity

Surface wettability patterning of metal additive manufactured parts via laser-assisted functionalization

Additive manufacturing (AM) has revolutionized the production of complex geometries with superior properties compared with traditional manufacturing methods. However, the high roughness and poor wettability of as-produced surfaces of AM parts limit their suitability for certain applications. To address this, we present a maskless laser-assisted surface functionalization method to improve the wettability of metal 3D printed parts. This study explores the potential of combining metal AM with surface wettability patterning, a promising technique in fluid-related fields. Large-area AlSi10Mg parts were fabricated using laser powder bed fusion (L-PBF), followed by an innovative laser-assisted functionalization (LAF) method to achieve patterned wetting surfaces. The LAF method consists of laser texturing and chemical modification steps, and two strategies were demonstrated to fabricate different types of wettability patterns. Strategy I helps produce two types of superhydrophobicity, while strategy II helps create a superhydrophobic-superhydrophilic patterned surface. The study demonstrates the simplicity, robustness, and feasibility of the process and analyzes the processing mechanism, surface topography, and surface chemistry. The integration of surface wettability patterning and 3D-printing can optimize components to enhance performance and efficiency by creating intricate fluid flow pathways. Overall, this work highlights the potential of combining metal AM with surface wettability patterning, providing a pathway to produce high-performance parts with tailored wettability properties. This research has significant implications for fluid-related industries such as aerospace, automotive, and energy, as it offers unparalleled design freedom and the ability to create complex geometries.

Dopamine-Regulated Plasticity in MoO3 Synaptic Transistors.

Field-effect transistor-based biosensors have gained increasing interest due to their reactive surface to external stimuli and the adaptive feedback required for advanced sensing platforms in biohybrid neural interfaces. However, complex probing methods for surface functionalization remain a challenge that limits the industrial implementation of such devices. Herein, a simple, label-free biosensor based on molybdenum oxide (MoO3) with dopamine-regulated plasticity is demonstrated. Dopamine oxidation facilitated locally at the channel surface initiates a charge transfer mechanism between the molecule and the oxide, altering the channel conductance and successfully emulating the tunable synaptic weight by neurotransmitter activity. The oxygen level of the channel is shown to heavily affect the device's electrochemical properties, shifting from a nonreactive metallic characteristic to highly responsive semiconducting behavior. Controllable responsivity is achieved by optimizing the channel's dimension, which allows the devices to operate in wide ranges of dopamine concentration, from 100 nM to sub-mM levels, with excellent selectivity compared with K+, Na+, and Ca2+.

Giant Magnetoresistance Based Biosensors for Cancer Screening and Detection.

Early-stage screening of cancer is critical in preventing its development and therefore can improve the prognosis of the disease. One accurate and effective method of cancer screening is using high sensitivity biosensors to detect optically, chemically, or magnetically labeled cancer biomarkers. Among a wide range of biosensors, giant magnetoresistance (GMR) based devices offer high sensitivity, low background noise, robustness, and low cost. With state-of-the-art micro- and nanofabrication techniques, tens to hundreds of independently working GMR biosensors can be integrated into fingernail-sized chips for the simultaneous detection of multiple cancer biomarkers (i.e., multiplexed assay). Meanwhile, the miniaturization of GMR chips makes them able to be integrated into point-of-care (POC) devices. In this review, we first introduce three types of GMR biosensors in terms of their structures and physics, followed by a discussion on fabrication techniques for those sensors. In order to achieve target cancer biomarker detection, the GMR biosensor surface needs to be subjected to biological decoration. Thus, commonly used methods for surface functionalization are also reviewed. The robustness of GMR-based biosensors in cancer detection has been demonstrated by multiple research groups worldwide and we review some representative examples. At the end of this review, the challenges and future development prospects of GMR biosensor platforms are commented on. With all their benefits and opportunities, it can be foreseen that GMR biosensor platforms will transition from a promising candidate to a robust product for cancer screening in the near future.

Current Advances in Nanotheranostics for Molecular Imaging and Therapy of Cardiovascular Disorders.

Cardiovascular diseases (CVDs) refer to a collection of conditions characterized by abnormalities in the cardiovascular system. They are a global problem and one of the leading causes of mortality and disability. Nanotheranostics implies to the combination of diagnostic and therapeutic capabilities inside a single nanoscale platform that has allowed for significant advancement in cardiovascular diagnosis and therapy. These advancements are being developed to improve imaging capabilities, introduce personalized therapies, and boost cardiovascular disease patient treatment outcomes. Significant progress has been achieved in the integration of imaging and therapeutic capabilities within nanocarriers. In the case of cardiovascular disease, nanoparticles provide targeted delivery of therapeutics, genetic material, photothermal, and imaging agents. Directing and monitoring the movement of these therapeutic nanoparticles may be done with pinpoint accuracy by using imaging modalities such as cardiovascular magnetic resonance (CMR), computed tomography (CT), positron emission tomography (PET), photoacoustic/ultrasound, and fluorescence imaging. Recently, there has been an increasing demand of noninvasive for multimodal nanotheranostic platforms. In these platforms, various imaging technologies such as optical and magnetic resonance are integrated into a single nanoparticle. This platform helps in acquiring more accurate descriptions of cardiovascular diseases and provides clues for accurate diagnosis. Advances in surface functionalization methods have strengthened the potential application of nanotheranostics in cardiovascular diagnosis and therapy. In this Review, we have covered the potential impact of nanomedicine on CVDs. Additionally, we have discussed the recently developed various nanoparticles for CVDs imaging. Moreover, advancements in the CMR, CT, PET, ultrasound, and photoacoustic imaging for the CVDs have been discussed. We have limited our discussion to nanomaterials based clinical trials for CVDs and their patents.

Surface engineering and functionalization of MoS2-based nanoarchitecture for constructing epoxy composites with excellent fire resistance and mechanical properties

To overcome the shortcomings of epoxy resins (EP) such as high flammability and emission of toxic gases, a MoS2-based nanoarchitecture (CeZrOx-MoS2@PDA) was designed and prepared through surface engineering and functionalization method. At 2 wt% incorporation, the nanoarchitectures were homogeneously dispersed in EP matrix, showing good conditions for the formation of strong labyrinth barrier effect. Concurrently, EP/CeZrOx-MoS2@PDA offered enhanced thermal stability with higher char residues and lower maximum weight loss rate (MLR) value. Furthermore, the peak heat release rate (PHRR), total heat release (THR) and smoke factor (SF) of EP/CeZrOx-MoS2@PDA were reduced by 35.5%, 29.1% and 54.5%, respectively, while the CO release rate and CO2 release rate were dropped significantly, which was associated with the strong labyrinth effect, good char-forming effect and beneficial free radical quenching effect of CeZrOx-MoS2@PDA nanoarchitecture. Moreover, the ternary nanoarchitecture also resulted in a 56.8% increase in the storage modulus of EP composites. Therefore, the CeZrOx-MoS2@PDA developed in this work contributed to the generation of high performance EP with excellent fire resistance and mechanical properties, providing a promising strategy for the design of superior EP composites.

Probe type optical fiber DNA hybridization biosensor based on polyethylenimine and Poly-L-Lysine surface functionalization method

Nucleotide hybridization technology is an effective method for achieving optical-based selective recognition of nucleotides. Unfortunately, the optimal work performance is always restricted by the lack of the coupling method used to bind sensors with nucleotide sequences. In this work, a series of nucleotide hybridization detection experiments based on optical fiber surface plasmon resonance (SPR) are conducted, aimed at comparing the ability to bind nucleotide of Polyethylenimine (PEI) and Poly-L-Lysine (PLL), which are common coupling agents in optical-based nucleotide hybridization study. In our work, qualitative nucleotide measurements using PEI and PLL are carried out in positive order, negative order, and temperature fluctuation, and confirm PEI has a higher work performance in nucleotide-binding and nucleotide-detection. Quantitative determination in the concentration range of 0–100 nmol/L demonstrates the DNA sensitivity reaches 0.13 nm/(nmol/L) and the detection limit (DL) lies in 4.9 nmol/L, which is outstanding compared with similar optical sensors. In this paper, two kinds of nucleotide molecule detection methods based on optical fiber SPR sensing technology with PEI and PLL are proposed and experimentally verified, and the nucleotide-binding capability of PLL and PEI is contrast analyzed according to experimental results for the first time. This study is of great significance for improving the measurement scheme of DNA sensors and the selection of gene carriers for manufacturing DNA complexes.

Lipid-Polymer Hybrid Nanosystems: A Rational Fusion for Advanced Therapeutic Delivery.

Lipid nanoparticles (LNPs) are spherical vesicles composed of ionizable lipids that are neutral at physiological pH. Despite their benefits, unmodified LNP drug delivery systems have substantial drawbacks, including a lack of targeted selectivity, a short blood circulation period, and in vivo instability. lipid-polymer hybrid nanoparticles (LPHNPs) are the next generation of nanoparticles, having the combined benefits of polymeric nanoparticles and liposomes. LPHNPs are being prepared from both natural and synthetic polymers with various techniques, including one- or two-step methods, emulsification solvent evaporation (ESE) method, and the nanoprecipitation method. Varieties of LPHNPs, including monolithic hybrid nanoparticles, core-shell nanoparticles, hollow core-shell nanoparticles, biomimetic lipid-polymer hybrid nanoparticles, and polymer-caged liposomes, have been investigated for various drug delivery applications. However, core-shell nanoparticles having a polymeric core surrounded by a highly biocompatible lipid shell are the most commonly explored LPHNPs for the treatment of various diseases. In this review, we will shed light on the composition, methods of preparation, classification, surface functionalization, release mechanism, advantages and disadvantages, patents, and clinical trials of LPHNPs, with an emphasis on core-shell-structured LPHNPs.

Impact of Surface Functionalization and Deposition Method on Cu-BDC surMOF Formation, Morphology, Crystallinity, and Stability.

For direct integration into device architectures, surface-anchored metal-organic framework (surMOF) thin films are attractive systems for a wide variety of electronic, photonic, sensing, and gas storage applications. This research systematically investigates the effect of deposition method and surface functionalization on the film formation of a copper paddle-wheel-based surMOF. Solution-phase layer-by-layer (LBL) immersion and LBL spray deposition methods are employed to deposit copper benzene-1,4-dicarboxylate (Cu-BDC) on gold substrates functionalized with carboxyl- and hydroxyl-terminated alkanethiol self-assembled monolayers (SAMs). A difference in crystal orientation is observed by atomic force microscopy and X-ray diffractometry based on surface functionalization for films deposited by the LBL immersion method but not for spray-deposited films. Cu-BDC crystallites with a strong preferred orientation perpendicular to the substrate were observed for the films deposited by the LBL immersion method on carboxyl-terminated SAMs. These crystals could be removed upon testing adhesive properties, whereas all other Cu-BDC surMOF film structures demonstrated excellent adhesive properties. Additionally, film stability upon exposure to water or heat was investigated. Ellipsometric data provide insight into film formation elucidating 7 and 14 Å average thicknesses per deposition cycle for films deposited by the immersion method on 11-mercapto-1-undecanol (MUD) and 16-mercaptohexadecanoic acid (MHDA), respectively. In contrast, the films deposited by the spray method are thicker with the same average thickness per deposition cycle (21 Å) for both SAMs. While the spray method takes less time to grow thicker films, it produces similar crystallite structures, regardless of the surface functionalization. This research is fundamental to understanding the impact of deposition method and surface functionalization on surMOF film growth and to provide strategies for the preparation of high-quality surMOFs.

A simple surface engineering to develop the potential of carbon nitride nanosheets in high-performance polymer nanocomposites conducted by first-principles calculations

The incompatible interface between carbon nitride (CN) nanosheets and polymer resin is a huge challenge to develop high-performance polymer/CN nanocomposites. Recently, the complicated surface functionalization methods reported severely hinder the commercial production and practical application of polymer/CN nanocomposites. Herein, conducted by the first-principles calculations, a simple surface engineering is put forward to change the surface characteristic of CN nanosheets by rapidly introducing oxygen atoms with a chemical oxidation method. Presented by the first-principles calculations, it is found that the introduction of oxygen atoms can enhance the adsorption energy between oxygen-doping carbon nitride nanosheets (OCN) and waterborne polyurethane (WPU) resin. As a result, a stronger interfacial interaction and better dispersion state are presented in WPU/OCN nanocomposites, thus laying the foundation for the properties enhancement. Further, effective suppression effects for thermal pyrolysis and fire hazards of WPU resin are demonstrated by OCN nanosheets. As presented by cone calorimeter results, the peak values of heat release rate and total heat release in WPU/OCN-2 are decreased to 806 kW/m2 and 43.3 MJ/m2, significantly less than those of pure WPU (1028 kW/m2 and 55.9 MJ/m2). Meanwhile, more char residue, lower signal intensity of pyrolysis gas, and a prolonged time for signal peak also confirm that the addition of 2.0 wt% OCN nanosheets can hinder the thermal degradation behavior of WPU resin. In addition, the introduction of oxygen atoms promotes the formation of hydrogen bond interactions between OCN nanosheets and WPU matrix, thus enhancing interfacial compatibility and overcoming the re-stack problem. As a result, break strength and elongation at break of WPU/OCN-2 are up to 621% and 24.4 MPa, respectively. The combination of first-principles calculations and surface engineering opens a new approach for designing and developing high-performance polymer nanocomposites.

PdIr nanoparticles on NH2-functionalized dendritic mesoporous silica nanospheres for efficient dehydrogenation of formic acid

Developing highly efficient solid catalysts for formic acid (HCOOH, FA) dehydrogenation is essential to utilize FA as a hydrogen (H2) carrier. In this work, ultrafine bimetallic PdIr nanoparticles (NPs) supported on the amine-functionalized dendritic mesoporous silica nanospheres (PdIr/DMSNs-NH2) have been successfully synthesized by the simple surface functionalization and co-reduction method. The optimized Pd4Ir1/DMSNs-NH2 (Pd/Ir molar ratio = 4:1) catalyst displayed the remarkable catalytic performance with 100 % H2 selectivity of the FA dehydrogenation, and the initial turnover frequency (TOF) could achieve 1333 h−1 with the additive of sodium formate (SF) at 298 K, which is comparable to the most effective mesoporous silica supported Pd-containing solid catalysts. The activation energy (Ea) for the FA dehydrogenation of Pd4Ir1/DMSNs-NH2 catalyst in the FA-SF mixture is 39.7 KJ/mol, lower than most reported catalysts. Furthermore, the optimized catalyst maintained 100 % H2 selectivity even after five runs, only with a negligible decrease in the activity, displaying the excellent stability of the catalyst. The superior catalytic performance could be attributed to the synergistic effect of open dendritic pore channel, high dispersion and ultrafine size of PdIr NPs as the active sites on DMSNs-NH2, and regulated electronic effects of Pd and Ir. More importantly, introducing –NH2 groups to the DMSNs could facilitate the O–H bond dissociation of FA and improve the FA dehydrogenation activity under mild conditions. This work will significantly promote FA as a hydrogen carrier on fuel cells.

Ligand chemistry for surface functionalization in MXenes: A review

AbstractSurface chemistry of MXenes is of significant interest due to its potential to control their final optoelectronic and physicochemical properties, and address the oxidation and dispersion stabilities of MXenes. Surface chemistry of MXenes can be manipulated by either MXene synthesis via chemical etching or post surface functionalization method. Although numerous reviews have explored MXene synthesis methods, there has been a lack of focus on post surface functionalization. This review aims to fill this gap by summarizing recent advancements in the MXene surface functionalization chemistry, and elucidating mechanisms, properties, and future perspectives of functionalized MXenes. We discuss organic ligand molecules, such as organic salts, catechols, phosphonates, carboxylates, and silanes, which can be employed to surface‐functionalize MXene through covalent or non‐covalent bond interaction. This comprehensive review offers valuable insights for scientists and engineers in utilizing functionalized MXenes across diverse applications, including EMI shielding, energy storage, electronics, optoelectronics, and sensors.image