High Reaction Rate Constant Research Articles

Boron-based combustion modifiers on combustion performance of boron-based fuel-rich propellants

Abstract This paper investigates the effects of different boron-based combustion modifiers on the rheological, combustion and energy release characteristics of boron-based fuel-rich propellants. The results show that boron-based high-energy ionic salts (B1, B2, B3) and boron-based metallic fuels (Mg-Al-B), when combined with (AB+TAB)/HTPB mixed systems, exhibit superior rheological characteristics. The B2 and Mg-Al-B agglomerated particles demonstrate low apparent activation energy and high reaction rate constants, facilitating the rapid combustion of boron-based fuel-rich propellants. Furthermore, the synergistic catalytic effect of B2 and Mg-Al-B increases the static burning rate pressure index from 0.38 to 0.54 at 0.5∼5 MPa, with a dynamic pressure index of 0.52. These modifications improve the energy release efficiency η c1 of the propellant, the energy release efficiency η c2 of the primary combustion, and the combustion efficiency η B of boron powder by 12.93%, 24.61%, and 34.06%, respectively. The primary injection efficiency exceeds 98%, significantly enhancing the combustion performance and energy release efficiency of boron-rich fuels.

Nitrite leads to the formation of N-nitrosodimethylamine during sulfate radical oxidation of dimethylamine compounds

Sulfate radical (SO4•−) advanced oxidation processes (SR-AOPs) are efficient for degrading a broad spectrum of contaminants. This study demonstrates that the existence of environmentally relevant concentrations of nitrite (NO2−) can lead to the formation of N-nitrosodimethylamine (NDMA), a probable human carcinogen, when heat activated peroxydisulfate (heat/PDS) is applied to address contaminants with dimethylamine moieties, such as tetracyclines. NO2− effectively competes with tetracyclines for SO4•− at a high second-order reaction rate constant of 8.8 × 108 M−1s−1, thus suppressing the degradation. Simultaneously, SO4•− reacts with NO2− to form the nitrogen dioxide radical (NO2•) which rapidly dimerizes to a potent nitrosating agent named dinitrogen tetroxide (N2O4). N2O4, in turn, attacks the dimethylamine moiety in tetracyclines via nucleophilic substitution, contributing to the degradation of parent compounds and generating an active intermediate that quickly decomposes to NDMA, along with the release of R+ and NO3−. The released R+ can be further oxidized by SO4•− to form phenolic intermediates which combine with NO2• to generate nitrated products. When 5 μM oxytetracycline (OTC) was treated with 0.5 mM PDS in the presence of 20 μM NO2− at 60 °C, the highest formation of NDMA was 0.045 μM in 1 h. NDMA formation was also observed for other compounds with dimethylamine moieties, such as methylene blue, phenylurea herbicides, etc., with the molar yield ranging from 0.07 to 3.53 %, negatively related to the R-N bond dissociation energy of the precursors. These findings suggest that NDMA can be commonly generated when SO4•− is applied to the degradation of dimethylamine pollutants in wastewater treatment or groundwater remediation where NO2− ubiquitously exists, which may pose a serious threat to the aquatic environment.

Waste upcycling of Sapota peels as a green route for the synthesis of silver nanoparticles and their application as catalytic and colorimetric detection of Co2+ and Hg2+

Biochemical synthesis of nanoparticles (NPs) using plant part extracts as capping and reducing agents has drawn considerable attention in research with a growing focus on green chemistry. The present study utilized Sapota (Manilkara zapota L.) peel extract to synthesize silver nanoparticles (SP-AgNPs) using ultrasonic vibration. Different characterization techniques such as UV-vis spectroscopy, dynamic light scattering, Fourier Transform Infrared Spectroscopy, Field emission scanning electron microscope, High resolution transmission electron microscopy, and X-ray diffraction were employed to check the production of SP-AgNPs. The AgNPs were crystalline in nature and had an average particle size of 27.906 nm. The research primarily focused on two aspects: the catalytic activity of SP-AgNPs in degrading environmental pollutants and their ability to act as colorimetric sensors for toxic metal ions. SP-AgNPs exhibited significant catalytic activity in the decomposition of various pollutants such as Methyl Orange (0.035 ± 0.090 min−1, 92.89 ± 1.79%), Crystal Violet (0.1097 ± 0.1016 min−1, 85.56 ± 2.21%) and Cosmic Brilliant Blue G-250 (0.0697 ± 0.0275 min−1, 79.56 ± 1.80%). The high degradation percentages and reaction rate constants indicate the efficiency of SP-AgNPs in pollutant degradation. Additionally, the study demonstrated the effectiveness of SP-AgNPs as sensors for detecting toxic metal ions, particularly Co2+ and Hg2+ with limits of detection 54.40 ± 1.43 µM and 10.70 ± 0.16 µM. With impressive sensitivity and low detection limits, SP-AgNPs showed promise in detecting these ions, which are often found in environmental contaminants. Moreover, their plant-based synthesis, low toxicity, and cost-effectiveness make them attractive options for environmental remediation efforts.Graphical abstract

Efficient enhancement of piezo-catalytic activity of BaTiO3-based piezoelectric ceramics via phase boundary engineering

Piezoelectric catalysis stemmed from lead-free piezoelectric ceramics is an emerging catalytic technology applied extensively in degradation of organic pollutants due to its low energy consumption and non-pollution. However, the dissatisfied catalytic efficiency of lead-free piezoelectric ceramics has constrained their further development and application. Herein, we employ ion doping to modulate the phase boundary construction of BaTiO3-based piezoelectric ceramics (BaTi(1-x)(Zr1/3Sn1/3Hf1/3)xO3, BTZSH-x), and the degradation performances of organic dyes are explored to illuminate the piezo-catalytic mechanism. The ion doping alters the phase boundary of BaTiO3 ceramics and a two-phase coexistence of rhombohedral-orthorhombic is achieved at room temperature in BTZSH-0.04 ceramic. Consequently, the BTZSH-0.04 ceramic exhibits an excellent degradation efficiency of rhodamine B with 97.27% in 60min and a high reaction rate constant of 0.056 min−1 under ultrasonication which is 7.4 times more than that of pristine BaTiO3. This work provides an advisable policy for constructing environmental-friendly piezoelectric materials with glorious piezo-catalytic activity.

Energy band gap tuning of Ba-Ca hexagonal ferrite by Dy3+ ion substitution (0 ≤ x ≤ 0.2) to improve spectral, structural, dielectric and photocatalytic properties

In the present study, Dy3+ substituted M-type Ba0.5Ca0.5DyxFe12-xO19 (0.00 ≤ x ≤ 0.20) hexagonal ferrites were synthesized using sol-gel auto-combustion method with lemon extract as a fuel. The single hexaferrite phase with space group P63/mmc is revealed by the X-ray powder diffraction (XRD) patterns. The Field emission scanning electron microscopy (FESEM) exhibits the agglomeration of nanoplates with vacancies at some places. Energy dispersive X-ray photoelectron spectroscopy (EDAX) mapping confirmed the presence of Ba, Ca, Fe, O, and Dy in the hexaferrite. Fourier Transform Infrared (FTIR) spectroscopy exhibits two characteristic bands at 579 and 429 cm−1 corresponding to tetrahedral and octahedral metal ions-oxygen stretching, revealing the occurrence of the ferrite phase. The optical energy band gap calculated using the Tauc plots was found to increase with the increase in dysprosium substitution to fall within the range of 2.8–3.5 eV. The Raman spectra confirmed the Raman vibration modes and M-type structures of hexagonal ferrites (HFs). The dielectric constant values drop rapidly with increasing frequency up to a few KHz and then gradually for the further higher frequencies. The occurrence of Ba and Ca with 2+, while Dy, and Fe with 3+ oxidation states is confirmed using X-ray photoelectron spectroscopy (XPS). The HFs exhibit remarkable efficiency by degrading the Reactive Brown dye to 99.3 % in just 15 min, equivalent to a high degradation reaction rate constant (k) value of up to 0.0396 min−1. Consequently, the catalyst shows promising potential for environmental remediation.

Optimizing catalytic performance of Ag2O/Na0.5Bi0.5TiO3 heterojunction by the piezo-phototronic coupling effect

The constructing of heterojunction piezo-photocatalysts has been regarded as a promising strategy in environmental remediation. Herein, a novel Ag2O/Na0.5Bi0.5TiO3 (Ag2O/NBT) p-n heterojunction is designed by using a facile method, inducing the remarkable enhancement of photocatalytic performance by piezoelectric effect under ultrasonic vibration. The Ag2O/NBT heterojunction can degrade 99 % Rhodamine B (RhB) within 30 min when exposed to light irradiation and ultrasonic vibration simultaneously, with a high reaction rate constant of 0.140 min−1, which is 4.5 times and 17.5 times that of individual photocatalysis (0.031 min−1) and piezocatalysis (0.008 min−1), respectively. Moreover, the Ag2O/NBT heterojunction exhibits excellent stability and reusability after five cycles. The improved piezo-photocatalytic performance can be attributed to the formation of p-n heterojunction and the generation of built-in electric field, which makes a high separation of photogenerated carriers. Finally, a possible piezo-photocatalytic mechanism for removal RhB was proposed based on the radical trapping experiment. It is expected that the results can provide valuable information for the further investigations of Ag2O/NBT heterojunction as a potential piezo-photocatalyst in the environmental remediation.

Synthesis of Alpha Ferrous Oxalate Dihydrate from Ferrotitaniferous Mineral Sands via Hot Pressurized Aqueous Oxalic Acid: Kinetics and Characterization

Ferrous oxalate dihydrate is a versatile organic mineral with applications across fields. However, little is known about the feasibility of its synthesis directly from iron-bearing minerals using binary subcritical water (sCW) systems and its associated kinetics. In this study, the sCW+oxalic acid system at either 115 °C or 135 °C was investigated as a reaction medium for ferrous oxalate dihydrate (α-FeC2O4∙2H2O) synthesis, starting from ferrotitaniferous sands. The kinetics of the synthesis reaction were studied, and the physicochemical characterization of the as-synthetized ferrous oxalates was performed. Overall, the sCW synthesis was temperature-dependent, following second-order reaction kinetics according to the proposed precipitation pathway. A high reaction rate constant, significantly high yields (up to 89%), and reduced reaction times (2–8 h) were evident at 135 °C. The as-synthetized product corresponded to the monoclinic α-FeC2O4∙2H2O, showed relatively high specific surface areas (from 31.9 to 33.7 m2∙g−1), and exhibited band gap energies within the visible light range (~2.77 eV). These results suggest that α-FeC2O4∙2H2O can be synthesized using an organic dicarboxylic acid and iron-rich, widely available, low-cost mineral precursors. In addition, the as-prepared α-FeC2O4∙2H2O could be further optimized and tested for catalytic and visible light photocatalytic applications.

Catalytic Dechlorination of Three Organochlorides by Recyclable Nano-Palladium-Engineered Natural Sponge with Formic Acid

Catalytic dechlorination of organic chlorides by palladium (Pd) with HCOOH represents one of the most effective and promising techniques for environmental remediation. In this study, we adopted alkaline-modified porous natural sponge as support of a Pd nanocatalyst (Pd@M-Sponge) and HCOOH as a hydrogen source for the hydrodechlorination of florfenicol (FF), o-chlorophenol (o-CP), and p-chlorophenol (p-CP). Favorable conversion efficiency of FF, o-CP, and p-CP was achieved at 25 °C and atmospheric pressure attributed to the small diameter and high catalytic reactivity of the prepared Pd NPs, in addition to the slight internal mass transfer limitation of the prepared Pd@M-Sponge. High reaction rate constants were obtained even in the conditions of a low molar ratio of HCOOH to p-CP (10:1) and a high concentration of p-CP (500 mg/L). The prepared catalyst also demonstrated superior recyclability without any obvious decrease in catalytic reactivity in 20 successive p-CP dechlorination cycles. This work provides an ideal recyclable and cost-effective catalyst based on renewable and biocompatible natural material for the catalytic hydrodechlorination of chlorinated organic pollutants with formic acid and a new view for the exploration and designing of highly reactive and stable catalysts for hydrodechlorination.

TiO2 nanoparticle photoactivation and oxidation reactions in freshwater and marine systems: The role of radical scavengers

Titanium dioxide nanoparticles (TiO2-NP) present in wastewater effluent are discharged into freshwater and saltwater (i.e., marine) systems. TiO2-NP can be solar-driven photoactivated by ultraviolet (UV)-light producing reactive oxygen species including hydroxyl radicals (·OH). ·OH are non-selective and react with a broad range of species in water. In other studies, photoactivation of TiO2-NP has been correlated with oxidative stress and ecotoxicological impacts on plant and animal biota. This study examined the photoactivation of TiO2-NP in freshwater and saltwater systems, and contrasted the oxidation potential in both systems using methylene blue (MB) as a reaction probe. Maximum MB loss (51.9%, n = 4; 95% confidence interval 49.4–54.5) was measured in salt-free, deionized water where ·OH scavenging was negligible; minimum MB loss (1%) was measured in saltwater due to significant ·OH scavenging, indicating the inverse correlation between MB loss and radical scavenging. A kinetic analysis of scavenging by seawater constituents indicated Cl− had the greatest impact due to high concentration and high reaction rate constant. Significant loss of MB occurred in the presence of Br− relative to other less aggressive scavengers present in seawater (i.e., HCO3−, HSO4−). This result is consistent with the formation of Bromate, a strong oxidant that subsequently reacts with MB. In freshwater samples collected from different water bodies in Oklahoma (n = 12), the average MB loss was 13.4%. Greater MB loss in freshwater systems relative to marine systems was due to lower ·OH scavenging by various water quality parameters. Overall, TiO2-NP photoactivation in freshwater systems has the potential to cause greater oxidative stress and ecotoxicological impacts than in marine systems where ·OH scavenging is a dominant reaction.

Synergies of chemodenitrification and denitrification in a saline inland lake

The interconnection between biotic and abiotic pathways involving the nitrogen and iron biogeochemical cycles has recently gained interest. While lacustrine ecosystems are considered prone to the biotic nitrate reduction (denitrification), their potential for promoting the abiotic nitrite reduction (chemodenitrification) remains unclear. In the present study, batch incubations were performed to assess the potential for chemodenitrification and denitrification in the saline inland lake Gallocanta. Sulfidic conditions are found in top sediments of the system while below (5–9 cm), it presents low organic carbon and high sulfate and ferrous iron availability. Anoxic incubations of sediment (5–9 cm) and water from the lake with nitrite revealed potential for chemodenitrification, especially when external ferrous iron was added. The obtained isotopic fractionation values for nitrite (ɛ15NNO2) were −6.8 and −12.3 ‰ and therefore, fell in the range of those previously reported for the nitrite reduction. The more pronounced ɛ15NNO2 (−12.3 ‰) measured in the experiment containing additional ferrous iron was attributed to a higher contribution of the chemodenitrification over biotic denitrification. Incubations containing nitrate also confirmed the potential for denitrification under autotrophic conditions (low organic carbon, high ferrous iron). Higher reaction rate constants were found in the experiment containing 100 μM compared to 400 μM nitrate. The obtained ɛ15NNO3 values (−8.5 and −15.1 ‰) during nitrate consumption fell in the range of those expected for the denitrification. A more pronounced ɛ15NNO3 (−15.1 ‰) was determined in the experiment presenting a lower reaction rate constant (400 μM nitrate). Therefore, in Gallocanta lake, nitrite generated during nitrate reduction can be further reduced by both the abiotic and biotic pathways. These findings establish the significance of chemodenitrification in lacustrine systems and support further exploration in aquatic environments with different levels of C, N, S, and Fe. This might be especially useful in predicting nitrous oxide emissions in natural ecosystems.

Significantly optimized piezoelectric catalytic properties of surface functionalized Nano-BaTiO3

In piezoelectric catalysis, the interaction between reaction molecules and the catalyst surface is of great significance for designing highly selective reaction processes. In this study, chemically functionalized BaTiO3 nanoparticles were fabricated using the hydrothermal method, and the piezoelectric catalytic activity was evaluated for degradation dye reactants by ultrasonic vibration. Due to surface modification of BaTiO3 nanoparticles, the carboxyl groups will be applied on the surface of BaTiO3 nanoparticles, resulting in the reduction in particle size and an increase in specific surface area. The adsorption of the carboxyl groups on the surface can also improve the ability of the BaTiO3 nanoparticles to capture the organic dyes. A high piezoelectric catalytic reaction rate constant of 0.0716 min−1, together with a degradation efficiency of >90 % was achieved within 30 min under 60 kHz and 100 W ultrasonic conditions. These results show that the surface modification of BaTiO3 nanoparticles brought excellent performance of piezoelectric catalysis by controlling the precursor and hydrothermal parameters. This study provides a new method for the preparation of chemically functionalized piezoelectric catalysts and design of other new highly selective catalysts.

Cu/N co-doped biochar activating PMS for selective degrading paracetamol via a non-radical pathway dominated by singlet oxygen and electron transfer

The non-free radical oxidation pathway (PMS-NOPs) of peroxymonosulfate (PMS) holds significant promise for practical wastewater treatment applications, owing to its low oxidation potential, high PMS utilization rate, and robust anti-interference capability in the degradation of pollutants. A novel activator copper nitrogen co-doped porous biochar (Cu-N-BC) with rich defect edges and functional groups was obtained by adding Cu and N to the biochar matrix generated by sodium alginate through pyrolysis in this study. Under the condition of 1 mM PMS, 30 mg/L activator was used to activate PMS and achieve efficient degradation of 10 mg/L paracetamol (PCT) within 15 min, with a high reaction rate constants (kobs) of 0.391 min−1. The activation mechanism of the Cu-N-BC/PMS/PCT system was a non-radical activation pathway with the dominance of singlet oxygen (1O2) and the presence of catalyst-mediated electron transfer. The graphite nitrogen, pyridine nitrogen, and Cu–N coordination introduced by Cu/N co-doping, as well as the carbon skeleton and CO functional group of biochar, were considered active sites that promote the 1O2 generation. The Cu-N-BC/PMS system exhibits strong stability, eco-friendliness, effective mineralization, and interference resistance across diverse pH levels (3–11) and interfering ions, including Cl−, H2PO4−, NO3−, SO42−, and humic acid. Remarkably, it efficiently degrades PCT in tap and lake water, achieving a notable 63.73% TOC mineralization rate, with leached copper ions below 0.02 mg/L. This research introduces a novel method for obtaining metal nitrogen carbon activators and enhances understanding of PMS non-radical activation pathways and active sites.

Insight into the role of reactive species on catalyst surface underlying peroxymonosulfate activation by P–Fe2MnO4 loaded on bentonite for trichloroethylene degradation

In this study, bentonite supporting phosphorus-doped Fe2MnO4 (BPF) was synthesized and applied for PMS activation to degrade TCE. Morphology and structure characterization results indicated the successfully synthesized of BPF, and the BPF/PMS system not only featured high TCE removal (97.4%) but also high reaction rate constant (kobs = 0.0554 min−1) and PMS utilization (70.4%, kobs = 0.0228 min−1). According to the results of various experiments, massive oxygen vacancies on P–Fe2MnO4 alter its charge balance and facilitate the electron transfer process named adjacent transfer (direct electron capture by adsorbed PMS from adjacent TCE). Mn(III) is the main adsorption site for PMS, and the hydroxyl groups on the catalyst (Fe sites of P–Fe2MnO4, Si and Al sites of bentonite) can also offer binding sites for PMS. The hydrogen-bonded PMS on Fe(III) and Mn(III) sites will subsequently accept the discharged electrons to generate free radicals and high-valent metal species. Meanwhile, electron loss of HSO5− that chemically bonded to hydroxyl groups on bentonite will generate SO5•−, which will further produce 1O2 through self-bonding. the active species on the catalyst surface contribute 65% of TCE degradation in the heterogeneous catalytic oxidation system.

Distinguishable photorecycling of PVDF nanocomposites membrane for reactive yellow 145 dye and real industrial wastewater treatment by different photocatalytic processes

This paper investigates the photocatalytic performance and recyclability of PVDF-MWCNTs-TiO2 nanocomposite membranes for the treatment of textile wastewater under sunlight irradiation. The nanocomposites were fabricated by incorporating varying weight ratios of MWCNTs-TiO2 (1 %, 3 %, 6 %, and 9 %) into PVDF matrices using a solvent casting method. Optimal loading of MWCNTs-TiO2 at 9 wt% resulted in nanocomposites with enhanced surface area (94.15 m2/g), reduced band gap (2.38 eV), uniform dispersion of nanoparticles, and abundant surface hydroxyl groups. Under Xenon lamp irradiation, the optimized PVDF-9 %(MWCNTs-9 %TiO2) nanocomposite achieved a high apparent reaction rate constant (kapp) of 9.92 × 10−3 s−1 for photocatalytic degradation of the model dye Reactive Yellow 145. Significantly, when tested on-site at a Saudi Arabian textile facility over 6 months, this nanocomposite effectively reduced the chemical oxygen demand (COD) of real wastewater samples to regulatory limits of 1000 ppm under natural sunlight irradiation. The COD values were lowered from an initial 5050–6200 ppm to a final range of 785–945 ppm using the PVDF-9 %(MWCNTs-9 %TiO2) membrane. Furthermore, the optimized nanocomposite exhibited good recyclability, retaining around 87 % of its initial activity after 8 reuse cycles for industrial wastewater treatment. The excellent photocatalytic efficiency and reusability of the MWCNTs-TiO2 modified PVDF nanocomposite under solar irradiation highlight its promise as a sustainable membrane technology for environmental remediation.

Electron Redistribution in Iridium-Iron Dual-Metal-Atom Active Sites Enables Synergistic Enhancement for H2O2 Decomposition.

Developing efficient heterogeneous H2O2 decomposition catalysts under neutral conditions is of great importance in many fields such as clinical therapy, sewage treatment, and semiconductor manufacturing but still suffers from low intrinsic activity and ambiguous mechanism understanding. Herein, we constructed activated carbon supported with an Ir-Fe dual-metal-atom active sites catalyst (IrFe-AC) by using a facile method based on a pulsed laser. The electron redistribution in Ir-Fe dual-metal-atom active sites leads to the formation of double reductive metal active sites, which can strengthen the metal-H2O2 interaction and boost the H2O2 decomposition performance of Ir-Fe dual-metal-atom active sites. Ir-Fe dual-metal-atom active sites show a high second-order reaction rate constant of 3.53 × 106 M-1·min-1, which is ∼106 times higher than that of Fe3O4. IrFe-AC is effective in removing excess intracellular reactive oxygen species, protecting DNA, and reducing inflammation under oxidative stress, indicating its therapeutic potential against oxidative stress-related diseases. This study could advance the mechanism understanding of H2O2 decomposition by heterogeneous catalysts and provide guidance for the rational design of high-performance catalysts for H2O2 decomposition.

Impact of channel nanostructures of porous carbon particles on their catalytic performance.

Mesoporous carbon particles have great potential due to their unique structural properties as support materials for catalytic applications. Particle shapes and channel nanostructures of mesoporous carbon particles can determine the reactant/product transport efficiency. However, the role of the channel nanostructure in the catalytic reaction has not been much explored. Herein, we introduce a facile method to fabricate a series of porous carbon particles (PCPs) with controlled channel exposure on the carbon surface and investigate the impact of the channel nanostructure of the PCPs on the catalytic activity. By employing a membrane emulsification method with a controlled solvent evaporation rate, we fabricate block copolymer (BCP) particles with uniform size and regulated degrees of cylindrical channel exposed to the particle surface. Followed by the carbonization of the BCP particles, a low amount (1.3 wt%) of Pt is incorporated into the PCP series to investigate the impact of channel nanostructures on the catalytic oxidation reaction of o-phenylenediamine (OPD). Specifically, PCP featuring highly open channel nanostructures shows a high reaction rate constant of 0.154 mM-1 s-1 for OPD oxidation, showing 5.5 times higher catalytic activity than those of closed channel nanostructures (0.028 mM-1 s-1). This study provides a deeper understanding of the impact of channel nanostructure within mesoporous carbon particles on catalytic activity.

Modulating Narrow Bandgap in a Diacetylene Functionalized Woven Covalent Organic Framework as a Visible Light Responsive Photocatalyst.

Woven covalent organic frameworks (COF) possess three dimensional frameworks with spatially isolated Cu(I) centers and have promising optoelectronic properties because of metal to ligand charge transfer (MLCT). However, despite their potential, woven COFs have not yet been investigated as photocatalysts. In this study, we developed a new woven COF, Cu-PhenBDA-COF, functionalized with diacetylene bonds. Cu-PhenBDA-COF was fully characterized, and the optoelectronic and photocatalytic properties were compared to previously reported Cu-COF-505. The diacetylene bonds of the linker positively impacted the optoelectronic properties of Cu-PhenBDA-COF and resulted in a narrower band gap and better charge separation efficiency. When the Cu(I) center was removed from both woven COFs, the absorption edge was blue shifted, resulting in a wider band gap, and there was a considerable decrease in the charge separation efficiency, underscoring the pivotal role of MLCT. This trend was reflected in the photocatalytic activity of the woven COFs toward the degradation of sulfamethoxazole in water, where the highest reaction rate constant (k app ) was recorded for the metallated diacetylene functionalized woven COF, Cu-PhenBDA-COF.

Br-Doped BiOCl Nanosheet Exposed (001) Facet: Surface Oxygen Vacancy and Directed Electron Flow Boosting the Photocatalytic Performance.

The defective BiOCl nanosheet exposed (001) facet with favorable photocatalytic performance was designed. The surface microstructure analysis and theoretical calculation certified the dominant exposed (001) facet and rich surface oxygen defects of Br--doped BiOCl (B-6) nanosheets. The energy level structure analysis indicates that the band gap can be narrowed and the light absorption range can be widened by introducing Br- to BiOCl, and the presence of defective energy levels increases the photogenerated carrier transfer efficiency. Moreover, the doping of Br- in BiOCl promotes the directional flow of electrons to the surface of B-6, which improves the photocatalytic performance of the sample. Thus, the Br--doped BiOCl can degrade 96.5% RhB within 6 min under visible-light irradiation with high apparent reaction rate constants of 0.51 min-1, exhibiting the strongest photocatalytic degradation performance. This work provides guidance for the preparation of Bi-based photocatalysts with excellent performance.

Flexible metal membrane integrated electrified and catalytic attributes for multifunctional water purification with enhanced scaling resistance

Electrified and ceramic membranes assembled with rigid materials have been greatly appreciated for unique electrical responsiveness and catalytic properties for efficient water purification. However, the intensive van der Waals forces of traditional rigid materials have historically resulted in poor rejection, scaling resistance and mechanical properties to those of standard filters. In response, an innovative fabrication approach has been formulated, entailing induced fit theory inspired activation of inert polyamide (PA) substrates, concomitantly coupled with the in-situ growth of CoOx nanoflowers on the polymer membrane surfaces. This method yielded activated terminal amide groups that enable specific coordination in a manner akin to that of a zymogen activation. The ensuing development of CoOx nanoflowers engendered a notably rugged interface, prompting the emergence of grass-like membrane structures reminiscent of the lotus effect. The integration of CoOx nanoflowers endowed the resultant membrane augmented surface hydrophilicity, elevated rejection efficiency, exceptional conductivity, and degradation potential. These effects synergistically yielded an exceptional water permeability for the fabricated membrane (1.90×103 L·m−2·h−1), surpassing that of the CoOx-free control membrane by over twofold, coupled with a separation rate exceeding 99.8 %. Furthermore, interface engineering contributed to an exceptionally high reaction rate constant of the resultant membrane (2.93), surpassing that of the inherent membrane by over 167-fold. Importantly, the self-cleaning prowess, facilitated by CoOx, was evidenced by the recoverability of severely fouled membranes through PMS rinsing and electrical interaction. The mechanisms underlying the membrane's multifaceted antifouling performance were systematically unveiled through the extended Derjaguin-Landau-Verwey-Overbeek theory. By employing the facile and ingenious induced fit theory, this approach ushers forth an extraordinary avenue for water purification and scaling resistance applications, distinctly accentuating the innovative essence of this study.

A novel multifunctional magnetically recyclable BiOBr/ZnFe2O4-GO S-scheme ternary heterojunction: Photothermal synergistic catalysis under Vis/NIR light and NIR-driven photothermal detection of tetracycline

The threat of tetracycline (TC) to human health has become a significant issue that cannot be disregarded. Herein, in order to achieve effective degradation and high-sensitivity detection of TC, BiOBr/ZnFe2O4-GO (BOB/ZFO-GO) S-scheme heterojunction nanocomposites (NCs) have been prepared using hydrothermal method. GO with high light absorption capacity accelerated the electron transfer between BiOBr and ZnFe2O4 nanocrystals and extended the light absorption region of BOB/ZFO NCs. The optimal GO addition of BOB/ZFO-GO NCs could degrade TC solution of 10 mg/L in 80 min and have a high reaction rate constant (k) of 0.072 min−1 under visible/NIR light. According to calculations, the non-metal photocatalyst (BOB/ZFO-GO(2)) with the best degradation performance had a photothermal conversion efficiency of up to 23%. Meanwhile, BOB/ZFO-GO NCs could be recycled by magnetic field. The excellent photocatalytic and photothermal performance could be maintained even after several cycles. In addition, a photothermal detection sensor based on a photothermal material/specific recognition element/tetracycline sandwich-type structure was constructed for the trace detection of TC concentration with a detection limit as low as 10-4 ng/mL. This research provides a unique idea for the multi-functionalization of photocatalysts and has a wide range of potential applications for the identification and treatment of organic wastewater.