Hydroxyl Research Articles

Ultra flexible silica aerogel with excellent mechanical properties for durable oil-water separation

Flexible Silica aerogel has a broad application prospect in the field of oil-water separation due to its low density and high porosity. However, its poor mechanical properties limit its application and it is a challenge to improve its mechanical properties while maintaining its excellent oil absorption capacity. In this work, we add silica sol to the silica source system formed by vinyltrimethoxysilane (VTMS) and vinylmethyl dimethoxysilane (VMDMS) to prepare silica sol-reinforced flexible silica aerogels by ambient pressure drying. The introduction of silica sol provides more -OH groups that can be used as condensation sites. The hydrolysis products of VTMS and VMDMS undergo dehydration condensation reaction with these exposed -OH groups and co-polymerize, resulting in a more robust three-dimensional porous structure. Silica sol- reinforced vinyl flexible silica aerogel is prepared with excellent mechanical properties. Its maximum strain can reach 80% in 10 compression-decompression cycles without destroying its structure. Its hydrophobic angle was 145.7 °. Most particularly, compared to conventional flexible aerogel,when the silica sol-reinforced vinyl flexible silica aerogel is used in oil-water separation applications, it does not need to be dried after absorbing oil but only mechanically squeezed to expel the absorbed organic solvent. It can be reused hundreds of times, which greatly improves the efficiency of oil-water separation.

In-situ formed stable Pt nanoclusters on ceria-zirconia solid solutions induced by hydrothermal aging for efficient low-temperature CO oxidation

Pt nanoclusters (PtC) on the surface of ceria-zirconia solid solutions exhibit superior low-temperature CO oxidation activity compared to Pt single atoms (Pt1). However, the redispersion behavior of the PtC to Pt1 lowers the efficiency of CO Oxidation. In this work, the stable surface hydroxyl groups were constructed by high-temperature hydrothermal aging treatment. Specifically, the Pt1 catalyst (Pt/CZOe-SA) prepared by atom trapping was subjected to high-temperature hydrothermal treatment to obtain the stable PtC catalyst (Pt/CZOe-HT) with in-situ formed PtC. The experimental results showed that PtC with 2–3 nm size could achieve excellent low-temperature activity and thermal stability. In addition, the ab initio molecular dynamics and density functional theory calculations revealed the specific evolution process of dynamic dispersion for PtC with or without hydroxyl groups from the femtosecond scale, suggesting that the hydroxyl groups limited the dispersion of PtC in the form of “energy fence”. The hydrothermal treatment not only introduced high-temperature stable hydroxyl groups to improve the stability of the in-situ formed PtC, but also optimized the ratio of Pt1 and PtC, and then enhanced the low-temperature activity by the synergistic effect between Pt1 and PtC. The present work can provide theoretical guidance for developing high-performance and high-stability Pt-based catalysts.

Surface engineering and concentration-dependent emission activated flexible tunable fluorescence from lignin-based N-doped carbon dots

Achieving the flexible and tunable fluorescence of lignin-based N-doped carbon dots (LCDs) remains a win–win yet challenging strategy. In this study, combining the surface engineering and concentration regulation strategy enabled the flexible adjustment of LCDs fluorescence emission from blue to yellow regions (345 to 560 nm). The surface electron-donor –OH groups not only enhanced the photoluminescence quantum yield (PLQY) to 14.75 % but activated the spectral shift of reduced LCDs (RLCDs). These arose from the reinforced π-electron conjugation and generated new –OH-related extrinsic defects with elevating concentration. Conversely, the electron-withdrawing CO groups participated in the blue-to-green fluorescence modulation. Still, they drastically reduced the PLQY of oxidized LCDs (OLCDs) to 2.13 %, due to the larger particle size and more non-radiative transfer induced by CO groups. Based on these, CDs/PVA films and printed fluorescent patterns with multicolor fluorescence were realized for anti-counterfeiting, and the RLCDs@Al2O3 hybrid facilitated the precise fluorescence fingerprint tracking and recognition. This study provided a facile strategy for enriching and developing novel LCDs with flexible fluorescence for their advanced applications.

Studies on the effect of reactive dye on jute and jute blended fabrics

Jute is generally not dyed with reactive dye though it is a cellulosic fiber. While jute is dyed with basic dye, but cotton, viscose, and other cellulosic fibers are frequently dyed with reactive dye. In this study, a novel method for dying blended jute fabrics with reactive dye after bleaching them is presented. Two different reactive dye colors were used to treat this blended jute fabric. By contrasting samples of non-dyed grey blended jute fabric, the GSM, Water uptake percentage, and FTIR of dyed fabric were examined. It has been observed that the dyed sample's GSM (average 76) is higher than the grey fabrics GSM (average 65) due to the chemical modification of grey blended jute fabric. Blended jute fabric has a lower water absorption percentage while dyed sample has a higher absorption percentage such as 150% in 40 min and 145% in 140 min. Due to chemical modification of the surface of the blended jute fabrics, the FTIR spectrum report reveals that –OH group peak appeared in the wave number of 3291 cm−1 and the dyeability of the fabric is significant based on peak analysis.

Highly efficient removal of uranium (VI) from aqueous solutions by APTES/ATP

Abstract Uranium-containing wastewater poses a significant threat to both the ecological environment and human health. Adsorption is a crucial method for purifying uranium wastewater. Using 3-Aminopropyltriethoxysilane (APTES) to modify attapulgite (ATP), we successfully prepared a cost-effective and high-performance adsorbent material, APTES-modified attapulgite (APTES/ATP). This material was utilized for the purification of uranium-containing wastewater. Characterization techniques were employed to study the structure and surface properties of the material. The adsorption performance of the material was investigated using single-factor experiments. The adsorption isotherms, kinetics, and thermodynamics were also studied and discussed. The results indicated that APTES/ATP exhibited an adsorption capacity of 382.13 mg·g⁻¹ for uranium at room temperature. The adsorption process followed the Langmuir adsorption model and pseudo-second-order kinetics, indicating that the adsorption of uranium by the material was a monolayer chemisorption. Adsorption thermodynamics revealed that the process was endothermic and spontaneous. The adsorption mechanism primarily involved electrostatic attraction and interactions between -NH₂, Si-O, and -OH groups with uranium. In summary, the prepared APTES/ATP demonstrated excellent adsorption capacity for uranium and shows promise for the purification of uranium-containing wastewater.

Upcycling sugar beet waste into sustainable organo-nanocatalysis for carbon dioxide fixation and cyclic carbonate synthesis: a research design study

Environmental pollution is a major global issue due to the increase of various pollutants all over the world. Enhancing pollutant remediation strategies for environmental sustainability necessitates increasing the efficiency of conventional methods or introducing innovative approaches. Nanotechnology, particularly carbon-based nanomaterials, offers substantial promise due to their high surface area and absorption potential. Concurrently, organocatalysts have emerged as sustainable and versatile alternatives to traditional metal-based catalysts in modern chemical research. This study highlights the synthesis and application of organo-nanocatalysts derived from biomass, specifically a spherical carbon nanocatalyst synthesized from sugar beet pulp. This novel green catalyst, characterized by high selectivity and efficiency, successfully converts epoxides and CO2 into valuable cyclic carbonates under solvent-free conditions. The hydroxyl groups on the Sugar Beet-derived Carbon NanoSphere (SCNS) surface act as Bronsted acid sites, facilitating epoxide activation via hydrogen bonding. The integration of carbon-based nanomaterials and organocatalysis represents a promising, sustainable solution for pollutant remediation and green chemistry advancements.Graphical

Enhanced nanocellulose extraction from date palm waste: green solvent hydrolysis with transition metal complex

This study presents a novel method for nanocellulose production using [Bmim]Cl as a green solvent, with enhanced hydrolysis efficiency achieved through the addition of a transition metal complex as a catalyst. The redox capability of the transition metal complex to break the glycosidic bonds in cellulose is amplified by the addition of an oxidizing agent. This protocol represents the latest innovation in the field of nanocellulose production, resulting in improved yield and reduced particle size. Nanocellulose (NC) was extracted from date seeds using 1-butyl-3-methylimidazolium chloride [Bmim]Cl coupled with a transition metal complex comprising copper metal and pyridine as a ligand along with H2O2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{H}}_{2}{\ ext{O}}_{2}$$\\end{document} as an oxidizing agent. Unlike conventional [Bmim]Cl hydrolysis, which typically yields only microcrystalline cellulose (MCC), this approach resulted in a 25% higher yield of NC than that of MCC. Dynamic light scattering analysis showed a substantial reduction in hydrodiameter from 1200 nm for MCC to 128.7 nm for NC, highlighting the remarkable efficiency of this process. Thermal analysis demonstrated the high stability of NC, which showed a Tonset\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${T}_{onset}$$\\end{document} of 286 °C and an activation energy (Ea\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${E}_{a}$$\\end{document}) of 220.41 kJ/mol. X-ray diffraction analysis indicated that NC possessed a high degree of crystallinity (Crl=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${C}_{rl}=$$\\end{document} 70.28%). Furthermore, NC underwent modification with 3-aminopropyltriethoxysilane to replace free hydroxyl groups (–OH), making it redispersal and suitable for various applications. This modification was confirmed through Fourier transform infrared spectroscopy, which showed the presence of characteristic functional groups, and energy-dispersive X-ray spectroscopy, which verified the elemental composition. Zeta potential measurements revealed surface charge differences, with MCC at − 27.87 mV, NC at − 27.28 mV, and modified NC at − 44.72 mV, indicating improved colloidal stability after modification. These findings highlight the protocol's effectiveness and its potential impact on the NC production industry, offering improved yields and the production of nanosized fibers using green solvents.

A Comparative Analysis of Traditional Latent Fingerprint Visualization Methods and Innovative Silica Gel G Powder Approach

Latent fingerprints are a common source of information for forensic experts and law enforcement agencies. The thin layer chromatography (TLC) plates that are prepared in this work are made with silica gel G powder. Latent fingerprint remnants are made up of secretions from the nose, palm, and sebaceous, apocrine, and eccrine glands (sweat). However, the quest for more versatile and effective techniques persisted, leading to the emergence of innovative approaches like Silica Gel G powder. The silicon atoms are linked to –OH groups at the silica gel’s surface. A latent fingerprint is an imprint left by direct contact with a surface or object that is not apparent to the unaided eye. The advantages of using Silica Gel G powder for latent fingerprint visualization underscore its significance as an innovative technique in forensic science. The latent fingerprints were developed on each of the several substrates using Merck Specialties Private Limited’s white-coloured silica gel G powder. There are several techniques in the literature for creating latent fingerprints. The emergence of Silica Gel G powder in forensic science represents a significant breakthrough in the visualization of latent fingerprints. The process of using Silica Gel G powder for latent fingerprint visualization exemplifies the precision and attention to detail required in forensic investigations.

A theoretical simulation of carbon dioxide adsorption capture on amine-functionalized graphene oxides

Amine-functionalized graphene oxides (AFGOs) are potential candidates for CO2 capture applications, as the amine functional groups could act as effective sites, promoting CO2 adsorption strength and selectivity. However, the CO2 adsorption mechanism on AFGO appears to be ambiguous, particularly with no explicit identification of the chemically bonded species. In this work, density functional theory and microkinetic simulations were carried out to investigate the physical and chemical adsorption mechanisms and behavior between AFGO and CO2. Our findings indicate that the van der Waals and hydrogen bonding (HB) interactions constitute physical binding modes between the aminated GO and CO2. The chemical adsorption pathways on AFGO materials have been revealed by the transition state search method, in which the relevant CO2 adsorption species, including carbamic acid and carbamate, and their formation conditions were theoretically identified on AFGOs. The chemisorption mechanisms have been recognized to be the nucleophilic interaction between GO-supported amines and CO2, simultaneously assisted by the cooperative effect of multiple HB interactions. More specifically, the surface hydroxyl groups and water molecules can serve as proton transfer media and offer HB interactions, thus regulating the reaction activity and chemical adsorption species. This theoretical work presents a new insight into CO2-AFGO interaction mechanisms, which is valuable for designing aminated GO adsorbents.

Influence of accelerated aging on mechanical properties and aging behavior of glass fiber reinforced pipe

In this work, the accelerated aging test of GFRP in two thermal environments was conducted. The accelerated aging test was conducted at a constant temperature of 95°C for periods of 3000h to analyze and study the aging behaviors and mechanism under two environments. Resin defects caused by aging were found in the SEM images, and degradation of the fiber/resin interface was observed. Both the hoop tensile test and uniaxial compression test showed brittle fracture characteristics, and the strength of hydrothermal aging specimens decreased more significantly. Due to matrix degradation, uniaxial compression fracture after hydrothermal aging was observed that the resin exhibited poor adhesion. The decrease in the hardness of the outer resin layer was attributed to the development of the degree of molecular chain breakage. ATR-FTIR results showed that the accelerated aging process is accompanied by changes in the concentration of functional groups. The change in C-H intensity was attributed to the post-curing phenomenon. Accelerated aging resulted in the formation of carboxylic acids or esters and the introduction of hydroxyl groups. Thermogravimetric tests showed that accelerated aging did not change the thermal decomposition temperature of epoxy resins, but caused a decrease in resin content.

Stabilization of arsenic-cadmium co-contaminated soil with the iron-manganese sludge derived amendment: Effects and mechanisms

An iron-manganese sludge-derived amendment was proposed to remediate arsenic (As) and cadmium (Cd) co-contaminated soil, with a strong adsorptive capacity across pH 4 to 10. The Langmuir model defined maximum adsorption at 78.17 mg/g for As(III), 110.48 mg/kg for As(V), and 65.77 mg/g for Cd(II). The X-ray photoelectron spectroscopy (XPS) spectra provided insights into the chemical interactions: As was predominantly complexed or ligand exchanged with iron(hydr)oxides. In contrast, cadmium exhibited a tendency to bond with acylamino and carboxyl groups, in addition to the ferric hydroxyl groups. Notably, 42.15% of the adsorbed As(III) was oxidized into As(V) by Mn(IV) oxides present in the amendment. The soil-verification experiment demonstrated that an amendment dosage of 40 g/kg was efficacious in reducing the leaching concentration of As and Cd to maintained below the safety thresholds of 0.1 mg/L and 0.01 mg/L, respectively, for pH levels 4 to 11, meeting the Chinese Surface Water Quality Standard V (GB3838-2002). After the stabilization, the exchangeable fractions of As and the acid-soluble fractions of Cd were significantly reduced, with these elements being transformed into more stable forms. The amendment maintained the soil's neutral pH and adjusted the soil physicochemical properties. This article presents a holistic approach by examining the organic-inorganic composite of iron-manganese oxides with polyacrylamide, modified as a stabilizing amendment for As and Cd co-contaminated soil. This innovative amendment adeptly navigates the previously conflicting stabilization mechanisms for anionic and cationic metals. Offering dual advantages, the amendment not only remediates soil but also addresses the disposal of waste, presenting a win-win solution for environmental management.

Sulfonated Hydroxyaryl‐Tetrazines with Increased pKa for Accelerated Bioorthogonal Click‐to‐Release Reactions in Cells

Bioorthogonal reactions that enable switching molecular functions by breaking chemical bonds have gained prominence, with the tetrazine‐mediated cleavage of trans‐cyclooctene caged compounds (click‐to‐release) being particularly noteworthy for its high versatility, biocompatibility, and fast reaction rates. Despite several recent advances, the development of highly reactive tetrazines enabling quantitative elimination from trans‐cyclooctene linkers remains challenging. In this study, we present the synthesis and application of sulfo‐tetrazines, a class of derivatives featuring phenolic hydroxyl groups with increased acidity constants (pKa). This unique property leads to accelerated elimination and complete release of the caged molecules within minutes. Moreover, the inclusion of sulfonate groups provides a valuable synthetic handle, enabling further derivatization into sulfonamides, modified with diverse substituents. Significantly, we demonstrate the utility of sulfo‐tetrazines in efficiently activating fluorogenic compounds and prodrugs in living cells, offering exciting prospects for their application in bioorthogonal chemistry.

Investigation of the Interaction between Poly(trimethylene carbonate) and Various Hydroxyl Groups

The interaction of poly(trimethylene carbonate) (PTMC) with hydroxyl group compounds was investigated as a model for polymer blending with polysaccharides. While 1-butanol, 2-butanol, ethylene glycol, and 1,2-cyclohexanediol showed almost no detectable interaction with PTMC in both solution states with the 1H NMR and solid states with the FT-IR, glucose and cellobiose suggested a slight change in the spectral pattern in FT-IR analysis. The thermal properties of the blended samples of PTMC and these hydroxyl groups were also investigated. Although the blends of PTMC with 1-butanol and 2-butanol did not influence thermal degradation behaviors due to their low boiling points, the PTMC blend with a higher number of hydroxyl groups, especially glucose and cellobiose, tended to increase thermal resistance and glass transition temperature, hence showing the existence of an interaction through hydrogen bonding.

Chemistry of Formate and Water Ligands on Metal Oxide Cluster Nodes of Metal-Organic Framework hcp Hf-UiO-66: Keys to Understanding Reactivity of Paired μ2-OH and Defect Sites.

Many metal-organic frameworks (MOFs) incorporate nodes that are metal oxide clusters, and ligands that have been observed on these nodes include formates, acetates, water, hydroxyl groups, and others, all of which are potentially important in affecting reactivities for applications in separations, catalysis, and sensing. Formate is a common node ligand, arising from formic acid used as a modulator and from N,N-dimethylformamide used as a solvent in MOF syntheses. Yet only little work has been reported characterizing the reactivities of node formate ligands. Infrared spectra reported here show that formate bonds to two types of sites on the paired Hf6O8 nodes of hcp UiO-66, namely, defect and μ2-OH sites. Quantifying the number of formate ligands by 1H NMR spectroscopy of digested samples showed an almost equal number of formate ligands on the two sites, indicating the likelihood that they neighbor each other. These formate ligands interact with water molecules, reversibly switching their bonding from bidentate to monodentate. The formates on μ2-OH sites of hcp Hf-UiO-66 interact much more strongly with water than those on defect sites of the same node, and both interact more strongly than isolated defect sites of Hf-UiO-66. Correspondingly, the catalytic activities of hcp UiO-66 determined as turnover frequencies on each site are approximately twofold higher than those on UiO-66, bolstering the inference that methanol dehydration is catalyzed by a node defect site and a neighboring node μ2-OH site. The results show how MOFs, with their well-defined node structures, provide unprecedented opportunities to understand details of reactivities and catalysis on metal oxide clusters, in contrast to bulk metal oxide surfaces.

The nature of structural defects in ZIF‐8 revealed with 1H and 31P MAS NMR and X‐ray absorption spectroscopy

The metal‐organic frameworks (MOFs) attract interest as potential catalysts whose catalytic properties are driven by defects. Several methods have been proposed for the defects‐inducing synthesis of MOFs. However, the active species formed on the defective sites remain elusive and uncharacterized, as the spectroscopic fingerprints of these species are hidden by the regular structure signals. In this work, we have performed the synthesis of ZIF‐8 MOF with defect‐inducing procedures using fully deuterated 2‐methylimidazolate ligands to enhance the defective sites' visibility. By combining 1H and 31P MAS NMR spectroscopy and X‐ray absorption spectroscopy, we have found evidence for the presence of different structural hydroxyl Zn–OH groups in the ZIF‐8 materials. It is demonstrated that the ZIF‐8 defect sites are represented by Zn–OH hydroxyl groups with the signals at 0.3 and –0.7 ppm in 1H MAS NMR spectrum. These species are of basic nature and may be responsible for the catalytic activity of the ZIF‐8 material.

Impact of calcination technology on properties of calcined clays

Calcined kaolinitic clays are known to be very reactive pozzolans, and combined with limestone can enable significant clinker substitution in cementitious systems. Thermal activation of kaolinitic clays takes place when the hydroxyl groups are removed, leading to formation of an amorphous reactive structure. There are several technologies for clay activation, but the most used at industrial scale are flash and stationary calcination. The objective of this paper is to investigate the impact of the calcination regime on the properties of the calcined product. It presents the results of an experimental program carried out with a kaolinitic clay calcined at a flash calciner and at a laboratory furnace. Calcination brings about a drop in specific surface, and an increase of average diameter due to agglomeration, an effect more pronounced in stationary calcination. No major differences were found at the heat of hydration, CH consumption and phase assemblage for the fully dehydroxylated material. The flash calcined material had slightly better results mainly due to a finer PSD compared with the one stationary calcined. No major difference was found in water demand and compressive strength for both regimes. As expected, the main impact of the calcination regime is the agglomeration.

Sodium-Poor, Hydroxyl-Rich, Defective Na2Ti3O7 Prepared by γ-Irradiation and Its Enhanced Proton Conductivity.

The use of γ-irradiation to tailor the physicochemical properties of materials is not widely applied to layered alkali metal oxides. Herein, we show that γ-irradiation (up to 400 kGy) of Na2Ti3O7 leads to a sodium-poor, hydroxyl-rich analogue where the layered structure, plate-like morphology, and textural properties are preserved. The deintercalation of sodium ions modifies the Ti-O bond lengths and expands the unit cell; the latter is supported by density functional theory (DFT) calculations. 23Na solid-state NMR suggests the transport of the symmetric, 7-fold Na2 sites to an intermediate environment, which is closer to the asymmetric, 9-fold Na1 sites. An 8 wt % mass loss (1.4 mol water/mol titanate) is observed, indicating an increased concentration of protons/hydroxyls. These hydroxyl groups (i.e., lattice protons) possess higher thermal stability than solely surface-adsorbed ones in the nonirradiated sample. At 200-400 kGy, the proton conduction (50 °C and ∼70% RH) of ∼10-6 S·cm-1 is 1 order of magnitude larger than that in the nonirradiated sample; the relaxation time decreases from 30 to 2-6 μs with γ-irradiation. The γ-dose dependence of dielectric loss is also present and analyzed using the Jonscher universal power law, indicating the low-frequency dispersion behavior characteristics of high charge densities.

Effects of Ageing on Surface Properties of Biochar and Bioavailability of Heavy Metals in Soil

This study aims to explore the effects of biochar ageing on its surface properties and the bioavailability of heavy metals in soil. The biochar was subjected to chemical oxidation/dry–wet cycles (CDWs), chemical oxidation/freeze–thaw cycles (CFTs), and natural ageing (NT) to analyze changes in the elemental composition, pH, specific surface area, pore volume, and surface functional groups. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were applied to characterize the functional groups and microstructure, and the BCR sequential extraction method was employed to demonstrate the fractionation distribution of Cu, Cd, and Pb. The results showed that the CDWs and CFTs treatments significantly reduced the carbon content of the biochar (with a maximum reduction to 47.70%), increased the oxygen content (up to 49.17%), and notably increased the specific surface area and pore volume. The pH decreased significantly from 9.91 to 4.92 and 4.99 for the CDWs and the CFTs, respectively. The FTIR analysis indicated notable changes in hydroxyl and carboxyl functional groups, and the SEM revealed severe microstructural damage in biochar after the CDWs and CFTs treatments. The heavy metal fractionation analysis indicated that exchangeable Cu, Cd, and Pb significantly increased after the CDWs treatment, reaching 31.40%, 5.25%, and 6.79%, respectively. In conclusion, biochar ageing significantly affects its physicochemical properties and increases the bioavailability of heavy metals, raising concerns about its long-term remediation effectiveness.

Molecular Design Engineering Regulates the Ground-State Passivation Ability of Benzophenone Derivatives in Perovskite Solar Cells.

Intramolecular hydrogen bonding (H-bonding) involved in the excited-state proton transfer (ESPT) process results in benzophenone derivatives (BPDs) with an excellent ability to passivate defects. However, the BPDs are in a continuing dynamic transition process between the ground state and the excited state under light radiation conditions. The ground-state BPDs may lose their ability to passivate defects, resulting in an increased defect density of the perovskite. Therefore, enhancing the passivation ability of the ground-state BPDs can help to achieve the full passivation ability of their ground state to excited state. Herein, we have researched the various BPDs by density functional theory and found that intramolecular H-bonding can weaken the passivation ability of ground-state BPDs, but intramolecular H-bonding is indispensable in the ESPT process. To address the issue, we investigated the influence of electron-donor properties and dipole moments of hydroxyl (-OH), methoxy (-OCH3), and n-octyloxy (-OC8H17) groups in BPD molecules on their coordination capacity through molecular design engineering. Ultimately, 2-hydroxy-4-n-octyloxy-benzophenone (UV5) with strong electron-donor n-octyloxy (-OC8H17) and elongated carbon-chain structure was selected as an additive, which enhances the passivate defect capability in both the ground and excited states. As a result, the UV5-based champion device achieved a power conversion efficiency (PCE) of 24.46% and remained at 75% of the initial PCE with exposure to UV light. This work focuses on the defect passivation capability of ground-state BPDs for the first time and opens a new concept for applying BPDs in PSCs.

The nature of structural defects in ZIF-8 revealed with 1H and 31P MAS NMR and X-ray absorption spectroscopy.

The metal-organic frameworks (MOFs) attract interest as potential catalysts whose catalytic properties are driven by defects. Several methods have been proposed for the defects-inducing synthesis of MOFs. However, the active species formed on the defective sites remain elusive and uncharacterized, as the spectroscopic fingerprints of these species are hidden by the regular structure signals. In this work, we have performed the synthesis of ZIF-8 MOF with defect-inducing procedures using fully deuterated 2-methylimidazolate ligands to enhance the defective sites' visibility. By combining 1H and 31P MAS NMR spectroscopy and X-ray absorption spectroscopy, we have found evidence for the presence of different structural hydroxyl Zn-OH groups in the ZIF-8 materials. It is demonstrated that the ZIF-8 defect sites are represented by Zn-OH hydroxyl groups with the signals at 0.3 and -0.7 ppm in 1H MAS NMR spectrum. These species are of basic nature and may be responsible for the catalytic activity of the ZIF-8 material.