Catalytic Decomposition Of Hydrogen Peroxide Research Articles

Enhancing the Self-Propelled Motion of Hydrogen Peroxide Fueled Active Particles with Formic Acid and Other Oxygen Scavengers.

We report enhanced active particle motion in hydrogen peroxide-fueled self-diffusiophoretic active particle systems of up to 400% via addition of low concentrations of oxygen scavenging agents such as formic acid (as well as other organic acids, hydrazine, and citric acid), whereas active motion was inhibited at higher concentrations. Control experiments showed that enhanced motion was decoupled from catalytic hydrogen peroxide decomposition rate and insensitive to particle surface chemistry. Experimental results point to bulk oxygen scavenging as the cause for the enhanced active motion, representing a realization of recently predicted promotional effects of product sinks on self-diffusiophoretic motion. Diminished active motion at high oxygen scavenger concentrations was attributed to catalytic site blocking by adsorbed solute.

Controllable synthesis of amidoximated self-propelled tubular micromotors for enhanced uranium recovery: non-invasive mixing and on-the-move capturing

Micro-/nanomotors that combine attributes of autonomous movement and adsorption performance are attractive for efficient pollutant treatment. However, micro/nanomotors design still suffers from challenges including complex manufacturing processes, specific instrument demands and low yields. Herein, we proposed amidoxime-functionalized polydopamine tubular micromotors (DNBMs-AO) and demonstrated their application for rapid selective adsorption of uranium from contaminated seawater. The whole fabrication procedure is simplified and straightforward by curcumin templating and in-situ reduction/graft method. The manganese dioxide (MnO2) catalyst and amidoxime groups are subsequently anchored on the outer and inner side of nanotube surface. Besides, the distribution and amount of modified MnO2 and amidoxime groups can be manipulated via directly changing the reduction time. DNBMs-AO are driven and propelled by microbubbles produced by MnO2-triggered catalytic decomposition of hydrogen peroxide, which can reach high velocity at 302.6 μm s−1. The static adsorption results indicate that the adsorption of U(VI) onto DNBMs-AO can be better described by Langmuir model with the maximum adsorption capacity of 313.9 mg/g. Moreover, the motion of DNBMs-AO can efficiently improve the U(VI) diffusion under low H2O2 concentration, and enhance the adsorption kinetics to approximately 2.5 times. DNBMs-AO also exhibits high selectivity towards U(VI) and excellent performance stability, endowing its potential application in environmental engineering field.

Engineered CAR-NK Cells with Tolerance to H2O2 and Hypoxia Can Suppress Postoperative Relapse of Triple-Negative Breast Cancers.

Surgical resection is a primary treatment option for patients with triple-negative breast cancer (TNBC), but it is associated with a high rate of postoperative local and metastatic relapse. Although chimeric antigen receptor-engineered NK (CAR-NK) cell therapy can specifically recognize and eradicate tumor cells, its therapeutic potency toward TNBCs is markedly suppressed by the hostile tumor microenvironment, which restricts the infiltration, survival, and effector functions of CAR-NK cells inside tumor masses. In this study, HER1-overexpressing TNBC-targeted CAR-NK (HER1-CAR-NK) cells were genetically engineered with catalase to endow them with tolerance toward the high levels of oxidative stress and hypoxia inside TNBC tumors through the catalytic decomposition of hydrogen peroxide, which is a principle reactive oxygen species inside tumors, into O2. We refer to these cells as HER1-CAR-CAT-NK cells. Upon intratumoral fixation with an injectable alginate hydrogel, HER1-CAR-CAT-NK cells enabled sustained tumor hypoxia attenuation and exhibited markedly enhanced persistence and effector functions inside TNBC tumors. As a result, locoregional HER1-CAR-CAT-NK cell therapy not only inhibited the growth of local primary residual tumors but also elicited systemic antitumor activity to suppress the growth of distant tumors. This study highlights that genetic engineering of HER1-CAR-NK cells with catalase is a promising strategy to suppress the postoperative local and distant relapse of TNBC tumors.

Synthesis of Multi-Functional Graphene Monolayers via Bipolar Electrochemistry.

Graphene has gained substantial research interest in many fields due to its remarkable properties among many other two-dimensional materials. In this study, we propose a wireless electrochemical approach, bipolar electrochemistry, for the precise modification of single layers of graphene at predefined locations, such as distinct edges or corners, with a variety of metals or polymers, thus enabling the elaboration of multi-functional monolayer graphene sheets. We illustrate the concept e. g. by depositing multiple metals, or platinum and a catalyst-containing porous polymer on the same graphene sheet, but at separate corners. This configuration allows activating chemiluminescence on the polymer spot, and simultaneously generates the driving force for autonomous motion on the Pt side through the catalytic decomposition of hydrogen peroxide into oxygen bubbles. This integration of different chemical features on the same object, exemplified by these proof-of-principle experiments, enhances the functionality of two-dimensional materials, paving the way for the use of these hybrid materials for a variety of applications, ranging from sensing and catalysis to targeted delivery.

Composite demineralized bone matrix nanofiber scaffolds with hierarchical interconnected networks via eruptive inorganic catalytic decomposition for osteoporotic bone regeneration

Demineralized bone matrix (DBM) is one of the standard biomaterials used to fill surgical bone defects in general orthopedic procedures. However, current DBM products come in the form of powder or viscous solutions that fail to mimic the natural hierarchical structure of bone while also using large amounts of valuable material. To overcome this, compact fibrous DBM/polymer (fDBM) composites were prepared via electrospinning. Then, by exploiting the catalytic decomposition of hydrogen peroxide, oxygen pockets are formed in the scaffold imparting it with a hierarchical porous structure similar to bone (Op-fDBM). These pockets created by bubbles of oxygen help give the scaffold a mechanically stable shape while the incorporated DBM supports cell adhesion and growth. In vivo evaluations reveal that fDBM increased bone volume by 41.7 % while Op-fDBM increased bone volume by 68.6 %. Significant increases in regenerated bone volume with the use of minimal amounts of DBM in fiber form go to show the great potential of this work in the field of bone regeneration.

Design of poly(N-isopropylacrylamide) coated MnO2 nanoparticles for thermally regulated catalytic decomposition of H2O2

We report the synthesis of thermoresponsive poly(N-isopropylacrylamide) coated manganese dioxide nanoparticles for the catalytic decomposition of hydrogen peroxide (H2O2), with the goal of developing a temperature-controlled catalytic system.

The Extraction of Copper from Chalcopyrite Concentrate with Hydrogen Peroxide in Sulfuric Acid Solution

Research on chalcopyrite leaching represents a great challenge, given its importance as one of the most abundant copper minerals and its significant role in global copper extraction. This study aimed to evaluate the effects of different parameters on chalcopyrite leaching by hydrogen peroxide as a strong oxidizing reagent in sulfuric acid solution. A series of leaching tests were carried out to investigate the effect of the solid/liquid ratio, stirring speed, temperature, oxidant and acid concentrations, and lixiviant dosing method on copper extraction from chalcopyrite concentrate. The catalytic decomposition of hydrogen peroxide occurred in the investigated leaching system, as reflected in the obtained metal extraction values. Copper extraction was increased in the first 60 min of the reaction, after which it essentially ceased. The maximum final copper extraction of 64.5% was attained with 3.0 mol/L H2O2 in 3.0 mol/L H2SO4 at a temperature of 40 °C after 120 min of reaction. Due to the catalytic decomposition of hydrogen peroxide in the examined leaching system, the leaching experiment was performed with the periodic addition of lixiviant at specific time intervals as well. The dissolution process was described by the first-order kinetics equation with an apparent activation energy of ~39 kJ/mol. Finally, XRD and SEM-EDS analyses were used to characterize the leached residue, and the results showed that the formation of elemental sulfur on the chalcopyrite surface affected the dissolution process.

Phosphorus vacancy-rich FeP@Al2O3 catalyze hydrogen peroxide decomposition for wastewater purification: Catalytic mechanism and performance evaluation

In this work, phosphorus vacancies-rich (PV-rich) FeP@Al2O3 spheres with 4–6 mm were prepared by FeSO4 as initial material and porous Al2O3 as carrier. The formation of FeP@Al2O3 experienced oxidation, polymerization, load, transformation and phosphorization processes. PV-rich FeP@Al2O3 catalyst not only overcame the shortcomings of powder catalyst, such as easy loss and difficult recovery after reaction, but also exhibited high catalytic activity for the activation of H2O2 and the degradation of antibiotics and dyes. The high removal efficiencies were remained over 9 cycles. Mechanism research indicated that both Fe and P could activate H2O2 to generate •OH. Experimental and density functional theory calculation results showed that the formation of PVs allowed more electrons to be transferred to O2 to produce O2•−. The •OH and O2•− can effectively degrade pollutants in a batch reactor and a continuous degradation reactor. This study provided an essential reference for the rational design of high-performance Fenton-like catalyst to degrade organic wastewaters.

High-loaded single-atom Cu-N3 sites catalyze hydrogen peroxide decomposition to selectively induce singlet oxygen production for wastewater purification

Single-atom catalysts (SACs) have been widely used in Fenton-like water treatment, but studies on the selective induction of H2O2 to produce singlet oxygen (1O2) are rare. Herein, a carbon nitride supported high-loaded single-atom Cu-N3 catalyst (Cu-CN, Cu load is 15.46 wt%) is prepared to activate H2O2 to selectively form 1O2. Experimental and DFT calculation results reveal that the key factor for 1O2 production is the Cu-N3 coordination structure. Specifically, Cu-N3 coordination structure is conducive to decomposing H2O2 into·OOH/·O2-. Besides, the density of Cu-N3 sites is another key factor, high Cu-N3 site density is conducive to the rapid conversion of·OOH/·O2- to 1O2. Benefitting from the dominant role of 1O2, the Fenton-like degradation performance of Cu-CN/ H2O2 system is not disturbed under high salinity conditions, and the performance is significantly enhanced at high pH. This work represents an important reference in understanding SACs for activated H2O2 to generate 1O2.

DFT study on the catalytic decomposition of hydrogen peroxide by iron complexes of nitrilotriacetate.

The Fenton system in the presence of nitrilotriacetate (NTA) ligand is studied by DFT approach. The calculations show that complexation of Fe(II) with NTA significantly facilitates the H2 O2 activation. The ferric-hydroperoxo intermediate NTAFe(III)OOH predominantly decays via the disproportionation into NTAFe(II)OH2 and NTAFe(IV)O involving the formation of a μ-1,2-hydroperoxo-bridged biferric intermediate. In this mechanism, the bridged hydroperoxo is reduced by hydroperoxo ligand rather than by Fe(III). On the one hand, the NTAFe(III)OOH is sluggish to undergo hydrogen abstraction; on the other hand, it is a good nucleophile that may perform aldehyde deformylation. The present calculations suggest that both ˙OH and Fe(IV)O are generated in the NTA-assisted Fenton system. However, the polycarboxylate ligand provides a favorable environment for H2 O2 to accumulate around iron ion through hydrogen bonding. This promotes the quenching of Fe(IV)O by H2 O2 , rationalizing why the Fe(IV)O species is hardly detected in the NTA-assisted Fenton system.

Activity and stability of bifunctional perovskite/carbon-based electrodes for the removal of antipyrine by electro-Fenton process

Bifunctional perovskite/carbon-black(CB)/polytetrafluoroethylene(PTFE) electrodes for electro-generation and catalytic decomposition of hydrogen peroxide to oxidizing hydroxyl radicals have been fabricated. These electrodes were tested for electroFenton (EF) removal of antipyrine (ANT) as a model antipyretic and analgesic drug. The influence of the binder loading (20 and 40 wt % PTFE) and type of solvent (1,3-dipropanediol and water) was studied for the preparation of CB/PTFE electrodes. The electrode prepared with 20 wt % PTFE and water exhibited a low impedance and remarkable H2O2 electro-generation (about 1 g/L after 240 min, a production rate of ca. 6.5 mg/h·cm2). The incorporation of perovskite on CB/PTFE electrodes was also studied following two different methods: i) direct deposition on the CB/PTFE electrode surface and ii) addition in the own CB/PTFE/water paste used for the fabrication. Physicochemical and electrochemical characterization techniques were used for the electrode's characterization. The dispersion of perovskite particles in the own electrode matrix (method ii) exhibited a higher EF performance than the immobilisation onto the electrode surface (method i). EF experiments at 40 mA/cm2 and pH 7 (non-acidified conditions) showed ANT and TOC removals of 30% and 17%, respectively. The increase of current intensity up to 120 mA/cm2 achieved the complete removal of ANT and 92% of TOC mineralisation in 240 min. The bifunctional electrode also proved high stability and durability after 15 h of operation.

Evaluation of CAT Variants A-89T, C389T, and C419T in Patients with Vitiligo in the Saudi Population.

Background and Objectives: Vitiligo is a chronic autoimmune and depigmentation disorder in humans that manifests as whitening lesions. Reactive oxygen species (ROS) are involved in cell damage. Catalase (CAT) is a well-known oxidative stress regulator and is primarily responsible for the catalytic decomposition of hydrogen peroxide into water and oxygen. Based on previous case-control and meta-analysis studies, we assessed the prevalence of three single-nucleotide polymorphisms (SNPs) of the CAT genes A-89T (rs7943316), C389T (rs769217) and C419T (rs11032709) in participants with vitiligo and healthy controls in the Saudi population. Materials and Methods: We recruited 152 participants with vitiligo and 159 healthy controls for A-89T, C389T, and C419T SNP genotyping studies using PCR and RFLP analysis. Additionally, we performed linkage disequilibrium and haplotype analyses between vitiligo cases and controls. Results: The rs7943316 and rs11032709 SNPs of the CAT genes showed a positive association with vitiligo for both heterozygous genotypes and dominant genetic models (TT + AT vs. AA in A-89T and TT + CT vs. CC in C389T), in the CAT gene. Linkage disequilibrium analysis revealed a moderate linkage between rs7943316 and rs11032709 SNPs in vitiligo cases and controls. Haplotype frequency estimation revealed a significant association (p = 0.003) among the three SNP alleles. Conclusions: The rs7943316 and rs11032709 SNPs of the CAT genes were strongly associated with susceptibility to vitiligo.

Enhanced accumulation of bitumen residue in a highly concentrated tailings flow by microbubbles from in-situ catalytic decomposition of hydrogen peroxide

The massive volume of oil sands tailings has been one of the most challenging environmental issues. In this work, we experimentally explore a simple and effective approach to bitumen residue separation from a highly concentrated slurry flow of the artificial oil sands tailings. By utilizing microbubbles from in-situ catalytic decomposition of H2O2 at low concentrations, bitumen aggregation is enhanced on the top part of the hydrotransport pipeline. The microscopic image analysis revealed the in-situ formation of microbubbles and confirmed that magnetic particles present in the slurries contributed to the fast release of the gas products and bubble formation from hydrogen peroxide decomposition. A high-speed camera was applied to capture images of the tailings flow in the pipeline through a transparent view window. A large number of tiny bubbles were identified post to the injection of H2O2 to the slurry flow. More than 70 % bitumen could be recovered from a lab-scale pipeline loop within 30 mins after H2O2 injection. The bitumen recovery efficiency from the collected froth was quantitatively compared under seven conditions with varied dosages, the concentration of H2O2, and the amount of magnetic solids in the slurries. Our results confirmed that the total dosage of H2O2 is the dominant factor in in-situ microbubble formation for enhanced bitumen aggregation in the flow. Importantly, microbubbles were generated rapidly in the real mature fine tailings. The results from our study provide insights into the preferential distribution of oil residue in the flow during hydrotransport without the requirement for an additional device. Removal of oily residues from concentrated slurries may bring economical and environmental advantages.

The influence of transition metal ions on the oxidation of kraft pulp using hydrogen peroxide under mildly acidic conditions

Abstract Oxidation of kraft pulp using hydrogen peroxide under mild acidic conditions can be applied in order to obtain new functionality of the fibres, in the form of carbonyl groups. The hydrogen peroxide concentration must, however, be higher than consumed by the oxidation reactions meaning that the liquid must be recirculated to fully utilize the hydrogen peroxide. This paper investigates the consequences of recirculation of the oxidation liquor. It was found that recirculation results in an accumulation of ions of transition metals (copper, iron and manganese) in the oxidation liquor. The transition metal ions are known for catalytic decomposition of hydrogen peroxide, producing radicals which may react with carbohydrates, forming carbonyl groups as well as causing carbohydrate degradation. This was confirmed through the recirculation of oxidation liquor as well as through controlled addition of transition metals. At high transition metal ion concentration the reactions were fast and a severe degradation of carbohydrates was observed, accompanied by a rapid hydrogen peroxide consumption. The consequence of this, in an industrial context, is that the concentration of metal ions must be carefully controlled in order to add functionality to the cellulose without causing excessive degradation of carbohydrates or consumption of hydrogen peroxide.

Ion transfer voltammetric and LC/MS investigations of the oxidative degradation process of fentanyl and some of its structural analogs

Ion transfer voltammetry at a polarized ionic liquid membrane and LC/MS technique were used to investigate the oxidative time-resolved degradation of the frequently (mis)used opioid fentanyl and some of its structural analogs.The degradation is based on the reaction of opioids with hydroxyl radicals produced by the catalytic decomposition of hydrogen peroxide. Using the voltammetric technique, it was confirmed that the presence of Fe2+ions and hydrogen peroxide is essential in the degradation process of fentanyl(s). An increasing concentration of ferrous ions accelerates the described reactions, while the reaction rate is much less affected by the concentration of fentanyl.In an excess of ferrous ions, the course of the reaction can be approximated by a pseudo-first-order reaction with a half-time of 3.85 min. The generation of HO• radicals was proved to be the rate-determining step. Oxidative degradation processes of all investigated fentanyl-related drugs exhibit similar kinetics. A wide variety of fentanyl degradation products were detected and characterized using LC/MS analysis. Mono-, di- and trihydroxylated derivatives in several isomeric forms were observed most abundantly in a relatively short reaction time (5–30 min). The formation of norfentanyl has also been demonstrated.

Hydrogen peroxide decomposition in serpentine mini channel with silver catalyst

Micro thrusters were used to produce thrust in the order of a few Newtons to position satellites and other designed space objects. For such applications, monopropellant thrusters using hydrogen peroxide are preferred for their high maneuverability, accurate positioning, and attitude control. Hydrogen peroxide is a green monopropellant that forms the products (water and vapor) after it gets decomposed in contact with a catalyst. Complete catalytic decomposition of hydrogen peroxide is still a challenging task. In the present work, 30% of hydrogen peroxide concentration with silver catalyst (modified geometry) were used to increase reaction rate. The effect of silver placed at different locations in serpentine and straight mini channels (same dimensions) is analyzed. The analysis is done for a varied number of silver catalysts placed at different locations in serpentine and straight mini channels having a diameter of 0.25 cm. The serpentine mini channel shows better decomposition of hydrogen peroxide especially at shorter length of 10 cm than the straight mini channel with the same length of catalyst because of its better mixing capability due to non-uniformity in the flow field, especially at the bend sections. The results will be useful in determining the appropriate geometry and placement of the catalyst for efficient monopropellant decomposition.

Transient, Multiscale, Heterogeneous Model of Hydrogen Peroxide Decomposition for 3D-Printed Catalysts

Hydrogen peroxide thrusters rely on catalysts to generate steam and oxygen, and yet relatively little is known about the processes that occur within the catalyst bed. Previous models have assumed that both diffusional resistances and temperature differences between the catalyst and the fluid can be ignored. In this paper a 1D, multiscale, transient, heterogeneous, and diffusion-enabled model of catalytic hydrogen peroxide decomposition was developed and applied to a 3D-printed catalyst bed, which offers potentially significant benefits over conventional silver mesh catalysts. A triply periodic minimal surface was the chosen geometry. Simulation results suggest that the heterogeneous and diffusion-limited nature of the reaction cannot be ignored if accurate predictions about the catalyst bed performance are to be made. Through the newfound capabilities of the present model, the influence of various parameters, such as the hydrogen peroxide concentration, pressure, geometric unit cell size, bed void fraction, and support material, were characterized. Increasing the concentration, decreasing the unit cell size, and increasing the void fraction are all effective strategies for improving the performance of hydrogen peroxide thrusters, made possible by new catalytic materials and the advent of 3D-printing.

Highly sensitive competitive electrochemiluminescence immunosensor based on ABEI-H2O2 system with cobalt hydroxide nanosheets and bimetal PdAg as co-enhancer for detection of florfenicol.

Acompetitive electrochemiluminescence immunoassay was established based on the isoluminol-H2O2 (ABEI-H2O2) system catalyzed by cobalt hydroxide (Co(OH)2) to detect florfenicol residues in food. First , ultra-thin two-dimensional Co(OH)2 nanosheets were used as the catalyst of ABEI-H2O2 system, and excellent catalytic effects were acquired by catalytic decomposition of hydrogen peroxide with cobalt ions. Then, bimetal PdAg (Pd/Ag) alloy nanoparticles were used as a bridge to connect ABEI and antibody due to their good biocompatibility; Pd/Ag alloy nanoparticles also had a catalytic effect to further amplify the ECL signal in the system due to the synergistic catalytic effect of thebimetal. A competitive immunoassay strategy was used to detect florfenicol, where the florfenicol in the sample will compete with the antibody for the limited binding sites on the coating antigen. The ECL immunosensor for florfenicol detection shows high sensitivity, with a linear range from 10-4 to 102ngmL-1, and a detection limit of 3.1 × 10-5ngmL-1, where the scan potential was varied from 0 to 0.6Vvs Ag/AgCl. This work was the first to use Co(OH)2 nanosheets and bimetal PdAg catalytic signal amplification methods to design the sensor, which provides a novel, convenient and reliable strategy for ultra-sensitive detection of florfenicol, and other biological small molecules. A novel ECL immunosensor based on ABEI-H2O22.

Catalytic decomposition of hydrogen peroxide on nanoporous activated carbons: Effect of surface chemistry

Three different nanoporous activated carbons (NACs) were studied in the catalytic decomposition of hydrogen peroxide. The most active NAC catalysts are those produced from a macroporous vinyl pyridine resin. They can potentially be used in water treatment processes for catalytic oxidation of organic pollutants. The catalytic activity of NACs depends on the concentration of surface oxygen-containing groups. The oxidation of NACs with nitric acid solutions decreases the catalytic activity by 2 to 7 times. This decrease is explained by the deactivation of the active centers of the surface during oxidation. Thermal treatment of oxidized NACs in argon restores catalytic activity. This restoration occurs due to the removal of surface oxygen-containing groups and the regeneration of active centers. Some NAC catalysts obtained by thermal treatment of oxidized NAC samples at 800 °C have higher catalytic activity than the initial NAC samples.

Simple and green method for preparing copper nanoparticles supported on carbonized cotton as a heterogeneous Fenton-like catalyst

In this study, copper nanoparticles supported on carbonized cotton as a heterogeneous Fenton-like three-dimensional (3D) structure catalyst were constructed for catalytic degradation of polyvinyl alcohol (PVA), Rhodamine-B, and Reactive Red X-3B. Herein, cotton in natural fibers was used as a carbon source, which provides a new method for the preparation of catalysts supported by carbon materials. In copper@carbonized cotton nanoparticles (CCCNs), the carbon layer is produced during the calcination process, which not only enhances the conversion of Cu0 to Cu+/Cu2+, but also accelerates the electron transfer and promotes the catalytic decomposition of hydrogen peroxide (H2O2) to generate·OH radicals. In a wide pH range (3−7), the CCCNs/H2O2 system could effectively degrade PVA, and the removal rates of PVA and TOC were found to be 99.5% and 98.68%, respectively. The optimized experimental conditions are as follows: pH, 7; mass ratio of Cu(OH)2CO3 to cotton, 10:4; catalyst dosage, 2.6 g L−1; reaction temperature, 65 °C; H2O2 dosage, 0.16 g mL−1, and without adjusting pH. In addition to the high catalytic activity, CCCNs exhibited good stability and reusability due to the strong 3D carbon layer. The CCCN composite material has been proven to be ideal catalyst to enhance the removal rate of the heterogeneous Fenton-like reaction system in removing organic pollutants present in wastewater.