Peroxide Activation Research Articles

Reverse loading of inert Al2O3 onto active iron oxide for improved H2O2 activation and pollutant degradation

Developing heterogeneous iron-based catalysts with superior reactivity and stability is a long-term goal for hydrogen peroxide (H2O2) activation in Fenton-like technique for water remediation. Supported iron-based nanocomposites are of great interest due to their earth abundance, environmental friendliness, and tunable structure. However, existing iron-based Fenton catalysts are normally designed via the loading of iron-derived nanoparticles onto various inert substrates, where the surface reactive sites are hardly affected by the substrate. Here, we report the first example of reversely loaded FeOx-Al2O3 nanocomposite via overturning the loading direction, i.e., loading inert Al2O3 support onto reactive FeOx nanoparticles. The resultant FeOx@Al2O3-R catalyst demonstrated much improved reactivity for H2O2 activation and bisphenol A removal (by 14 times in terms of first-order rate constant) than its analog FeOx/Al2O3-T, which was prepared via the loading of FeOx nanoparticles onto inert Al2O3 support. Moreover, FeOx@Al2O3-R exhibited excellent stability with Fe leaching only one sixth of FeOx/Al2O3-T. Systematic characterization results revealed that the inert Al ions modify the electronic environment and properties of the surface Fe reactive sites. This work provides an alternative reverse loading strategy to traditional loading method for the preparation of iron-based nanocomposite catalyst that is highly efficient for H2O2 activation and pollutant removal.

Metronidazole degradation mechanism by sono-photo-Fenton processes using a spinel ferrite cobalt on activated carbon catalyst

A heterogeneous catalyst was prepared by anchoring spinel cobalt ferrite nanoparticles on porous activated carbon (SCF@AC). The catalyst was tested to activate hydrogen peroxide (HP) in the Fenton degradation of metronidazole (MTZ). SCF nanoparticles were produced through the co-precipitation of iron and cobalt metal salts in an alkaline condition. Elemental mapping, physico-chemical, morphological, structural, and magnetic properties of the as-fabricated catalyst were analyzed utilizing EDX mapping, FESEM-EDS, TEM, BET, XRD, and VSM techniques. The porous structure of AC enhanced the catalytic activity of SCF by a significant decrease in the agglomeration of SCF nanoparticles. The effectiveness of SCF@AC in Fenton degradation improved substantially when UV light and ultrasound (US) irradiations were induced, most likely due to the strong synergistic effect between the catalyst and these irradiation sources. The photo-Fenton system was more efficient than the Fenton, sono-, and sono-photo-Fenton processes eliminating both MTZ and TOC. It was found that AC not only dispersed SCF nanoparticles and improved the stability of the catalyst, but also provided a high adsorption capacity of MTZ, resulting in a faster degradation. After 60 min of the photo-Fenton reaction, the elimination efficiencies of MTZ (30 mg L−1) and TOC were 97 and 42.1% under optimum operational conditions (pH = 3.0, HP = 4.0 mM, SCF@AC = 0.3 g L−1, and UV = 6 W). SCF@AC showed excellent stability with low leaching of metal ions during the reaction. Radical and non-radical (O2•–, HO•, and 1O2 species), alongside adsorption and photocatalysis mechanisms, were responsible for MTZ decontamination over the SCF@AC/HP/UV system. A comprehensive study on the HP activation mechanism and MTZ degradation pathway was obtained through scavenging tests. The findings demonstrate that SCF@AC is an effective, reusable, and environmentally sustainable catalyst for advanced oxidation processes that can effectively remove organic pollutants from wastewater. This study offers valuable insights into the feasibility of employing SCF@AC catalysts in Fenton-based processes for the degradation of MTZ.

Investigating Ligand Sphere Perturbations on MnIII-Alkylperoxo Complexes.

Manganese catalysts that activate hydrogen peroxide carry out several different hydrocarbon oxidation reactions with high stereoselectivity. The commonly proposed mechanism for these reactions involves a key manganese(III)-hydroperoxo intermediate, which decays via O-O bond heterolysis to generate a Mn(V)-oxo species that institutes substrate oxidation. Due to the scarcity of characterized MnIII-hydroperoxo complexes, MnIII-alkylperoxo complexes are employed to understand factors that affect the mechanism of the O-O cleavage. Herein, we report a series of novel complexes, including two room-temperature-stable MnIII-alkylperoxo species, supported by a new amide-containing pentadentate ligand (6Medpaq5NO2). We use a combination of spectroscopic methods and density functional theory computations to probe the effects of the electronic changes in the ligand sphere trans to the hydroxo and alkylperoxo units to thermal stability and reactivity. The structural characterizations for both MnII(OTf)(6Medpaq5NO2) and [MnIII(OH)(6Medpaq5NO2)](OTf) were obtained via single-crystal X-ray crystallography. A perturbation to the ligand sphere allowed for a marked increase in reactivity towards an organic substrate, a modest change in the distribution of the O-O cleavage products from homolytic and heterolytic pathways, and little change in thermal stability.

An Overview of Environmental Catalysis Mediated by Hydrogen Peroxide

The use of hydrogen peroxide (produced in situ or ex situ) as the main agent in oxidative processes of environmental pollutant removal is widely studied. The degradation of water pollutants, such as dyes, pharmaceuticals, cosmetics, petroleum derivatives, and even pathogens, has been successfully obtained by different techniques. This review gives an overview of the more recent methods developed to apply oxidative processes mediated by H2O2 and other reactive oxygen species (ROS) in environmental catalysis, with particular attention to the strategies (Fenton-like and Bio-Fenton, photo- and electro-catalysis) and the materials employed. A wide discussion about the characteristics of the materials specifically studied for hydrogen peroxide activation, as well as about their chemical composition and morphology, was carried out. Moreover, recent interesting methods for the generation and use of hydrogen peroxide by enzymes were also presented and their efficiency and applicability compared with the Fenton and electro-Fenton methods discussed above. The use of Bio-Fenton and bi-enzymatic methods for the in situ generation of ROS seems to be attractive and scalable, although not yet applied in full-scale plants. A critical discussion about the feasibility, criticalities, and perspectives of all the methods considered completes this review.

A review of copper-based Fenton reactions for the removal of organic pollutants from wastewater over the last decade: different reaction systems.

In recent years, as global industrialization has intensified, environmental pollution has become an increasingly serious problem. Improving water quality and achieving wastewater purification remain top priorities for environmental health initiatives. The Fenton process is favored by researchers due to its high efficiency and ease of operation. Central to the Fenton process is a catalyst used to activate hydrogen peroxide, rapidly degrading pollutants, improving water quality. Among various catalysts developed, copper-based catalysts have attracted considerable attention due to their affordability, high activity, and stable performance. Based on this, this paper reviews the development of copper-based Fenton systems over the past decade. It mainly involves the research and application of copper-based catalysts in different Fenton systems, including photo-Fenton, electro-Fenton, microwave-Fenton, and ultrasonic-Fenton. This review provides a fundamental reference for the subsequent studies of copper-based Fenton systems, contributing to the goal of transitioning these systems from laboratory research into practical environmental applications.

Cu single atoms anchored on hydrangea-like carbon nitride for facilitating photo-Fenton: Role of Cu2+/Cu+ cycle

Single-atom photo-Fenton (PF) reaction is widely employed for the degradation of antibiotics and water disinfection. However, the key fundamental issues of the valence state cycling of single-atom metals and the activation of hydrogen peroxide (H2O2) in the PF process remain indistinct. Herein, we developed a catalyst donated as Cu single atoms anchored hydrangea-like carbon nitride (Cu-SA/CNH) with Cu−N4 coordination for PF reaction. Compared to pristine CNH, the Cu-SA/CNH exhibited a 2.42-fold increase in PF kinetics. The Cu-SA/CNH/PF system achieved 98.1% degradation efficiency of tetracycline and effectively inactivated Escherichia coli within 30 min. Density functional theory calculations demonstrated that the formation of Cu−N4 effectively improved the energy of the Cu d orbitals, leading to the generation of intermediate states that facilitated the Cu2+/Cu+ cycle. The adsorption capacity of Cu dxz orbitals on H2O2 increased nearly 10 times. This work provides valuable insights for enhancing single-atom PF activity to address environmental pollution.

Boosting hydrogen peroxide activation for the high-efficient removal of volatile dimethylsulfoxide over niobium-based catalysts

Dimethyl sulfoxide (DMSO) is an important solvent in numerous industries. The biodegrading process of DMSO is slow and produces toxic volatile compounds including CH3SCH3, CH3SH, and H2S. Hence, it is important to develop chemical methods for treating DMSO-containing wastewater. In the present work, niobium oxyhydroxide and niobium oxide were synthesized and used to activate hydrogen peroxide for the degradation of DMSO to DMSO2. The niobium oxyhydroxide catalyst exhibited much better catalytic activity for DMSO oxidation than niobium oxide. EPR spectra and radical scavenging experiments confirmed that O2•− and 1O2 are the main active species for the oxidation of DMSO. FTIR analysis and DFT calculation confirmed that the surface hydroxyl of niobium oxyhydroxide can be substituted by hydroperoxo group of H2O2 to form Nb−OOH group, which can directly oxidize DMSO or indirectly oxidize DMSO via O2•− and 1O2. However, H2O2 cannot form hydroperoxo group on the surface of niobium oxide, which might trigger the lower activity of niobium oxide catalysts than the niobium oxyhydroxide catalyst. The niobium oxyhydroxide catalyst exhibited good reusability and was promising for the treatment of DMSO-containing wastewater.

In situ single iron atom doping on Bi2WO6 monolayers triggers efficient photo-fenton reaction

Developing an efficient photocatalytic system for hydrogen peroxide (H2O2) activation in Fenton-like processes holds significant promise for advancing water purification technologies. However, challenges such as high carrier recombination rates, limited active sites, and suboptimal H2O2 activation efficiency impede optimal performance. Here we show that single-iron-atom dispersed Bi2WO6 monolayers (SIAD-BWOM), designed through a facile hydrothermal approach, can offer abundant active sites for H2O2 activation. The SIAD-BWOM catalyst demonstrates superior photo-Fenton degradation capabilities, particularly for the persistent pesticide dinotefuran (DNF), showcasing its potential in addressing recalcitrant organic pollutants. We reveal that the incorporation of iron atoms in place of tungsten within the electron-rich [WO4]2− layers significantly facilitates electron transfer processes and boosts the Fe(II)/Fe(III) cycle efficiency. Complementary experimental investigations and theoretical analyses further elucidate how the atomically dispersed iron induces lattice strain in the Bi2WO6 monolayer, thereby modulating the d-band center of iron to improve H2O2 adsorption and activation. Our research provides a practical framework for developing advanced photo-Fenton catalysts, which can be used to treat emerging and refractory organic pollutants more effectively.

Superoxide versus peroxide activation of dye decolorizing peroxidases for bioelectrocatalysis

Here we show that dye decolorizing peroxidases can be electrochemically activated for substrate oxidation without addition of exogenous H2O2, yielding activities similar or better than in their conventional operation. The method is based on the in situ generation of O2•−, •OH and H2O2. These species bind the heme to form catalytically competent oxoiron intermediates. Activation of the Pseudomonas putida enzyme is mainly mediated by O2•−, while those from Thermobifida fusca and Saccharomonospora viridis show preferential activation by H2O2. This differential reactivity is explained by the dynamics of a conserved distal aspartate residue. In contrast to previous reports on the Bacillus subtilis enzyme, none of the peroxidases studied here show significant •OH mediated activation, as this radical is quenched by reactive amino acids abundant in these proteins. These results pave the way for the development of bioelectrocatalytic reactors based on dye decolorizing peroxidases for water remediation and biomass processing.

Molybdenum carbide nanoclusters with ultrafast electron transfer ability promotes molecular oxygen selective electrocatalytic reduction to hydroxyl radicals for pollutant control

A treatment strategy of in situ generation and activation of hydrogen peroxide to degrade pollutants by the heterogeneous Fenton-like technology is promising for water pollution. However, the selective activation of oxygen to hydroxyl radicals (OH) by cathode materials is still challenging. Here, molybdenum carbide (MoC) supported on a heteroatoms-doped (N, P, S) carbon carrier catalyst was successfully prepared, which rapidly produced OH and degraded paracetamol (APAP) pollutants. A high APAP degradation efficiency with a specific energy consumption of 0.24 kWh g−1 TOC was achieved. After 10 sets of continuous operations, the APAP degradation rate remains unchanged. Combined with density functional theory calculations, molecular oxygen adsorption obtains one electron with proton hydrogen transfer to hydroperoxyl (OOH) on the MoC surface, and the adsorbed OOH directly activate into OH due to the ultrafast electron transfer ability of MoC. Differential charge density analysis also shows that Mo transfers electrons to O. This strategy provides a new idea for optimizing catalysts to improve the heterogeneous Fenton-like performance.

Nitrogen-doped metal-free granular activated carbons as economical and easily separable catalysts for peroxymonosulfate and hydrogen peroxide activation to degrade bisphenol A.

The fabrication of low-cost, highly efficient, environmentally friendly, and easily separable metal-free heterogeneous catalysts for environmental remediation remains a challenge. In this study, granular nitrogen-doped highly developed porous carbons with a particle size of 0.25-0.30mm were prepared by preoxidation and subsequent NH3 modification of a commercially available coconut-based activated carbon, and used to activate peroxymonosulphate (KHSO5) or hydrogen peroxide (H2O2) to degrade bisphenol A (BPA). The nitrogen-doped carbon (ACON-950) prepared by NH3 modification at 950°C, with the addition of only 0.15g/L could remove 100% of 50mg/L BPA in 150min, and more than 90% of the removed BPA was due to degradation. The removal rates of total organic carbon of ACON-950/KHSO5 and ACON-950/H2O2 systems reached 60.4% and 66.2% respectively, indicating the excellent catalytic activity of ACON-950. The reaction rate constant was significantly positively correlated with the absolute content of pyridinic N (N-6) and graphitic N (N-Q) and negatively and weakly positively correlated with pyrrolic N (N-5) and defects. Quenching experiments combined with electron paramagnetic resonance demonstrated that singlet oxygen was the dominant reactive oxidative species for BPA degradation. ACON-950 was characterized before and after the degradation reaction using N2 adsorption-desorption analyzer, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results confirmed the prominent contribution of both the N-6 and N-Q to the catalytic performance of nitrogen-doped carbons. The reusability of ACON-950 and its application in actual water bodies further demonstrated its remarkable potential for the remediation of organic pollutants in wastewater.

Ferrate(VI)/percarbonate for the oxidation of micropollutants: Interactive activation and release of low-concentration hydrogen peroxide for efficient electron utilization

A novel "ferrate/percarbonate (Fe(VI)/SPC) co-oxidation process" was used to treat ciprofloxacin (CIP) and various micropollutants (MPs), which owned better performance than mixture of Fe(VI), Na2CO3 and H2O2. The mechanism investigation found that the low-concentration H2O2 (1–2 µM) released by SPC can promote the high-valent iron intermediates (Fe(IV)/Fe(V)) of Fe(VI) to the MP oxidation, and Fe(VI) products can also activate SPC to produce hydroxyl radical (·OH). The interactive activation of Fe(VI) and SPC was realized, which retained the high selectivity of Fe(VI) to electron-rich pollutants, and also made up the oxidation of electron-deficient pollutants through •OH, improving the degradation effect of various MPs by 20–30%, and the rate constant was increased by 1 to 3 times. Moreover, non-purgeable organic carbon (NPOC) determination confirmed that •OH participation reduced the NPOC value of CIP from 5.43 mg/L to 4.37 mg/L. The transformation pathway of CIP showed that Fe(VI)/SPC resulted in more hydroxylation intermediates of CIP than Fe(VI) alone. Acute toxicity assays found that the photoinhibition rate of CIP treated with Fe(VI) alone was 14.5%, while the sample treated with Fe(VI)/SPC showed no significant photoinhibition effect, which proved that the new process had good detoxification properties for CIP.

Three-dimensional electro-Fenton system with steel-slag based particle electrode for the treatment of refinery spent caustic

Refinery spent caustic (RSC) is a highly contaminated wastewater originated from the petroleum refining industry with complicated chemistry and high toxicity. In this work, a novel three-dimensional electro-Fenton (3DEF) system assisted by electromagnetic induction was developed to treat an actual RSC with a chemical oxygen demand (COD) concentration of 27000–33000 mg/L. Industrial waste steel slag was used as both the particle electrode and the Fenton’s catalyst. Under optimal conditions, COD removal reached 93.6% within 90 min. Electromagnetic induction significantly enhanced COD degradation by promoting the corrosion of steel slag, inhibiting the electrode passivation, and enhancing the thermal activation of hydrogen peroxide. The reusability of steel slag was also enhanced by electromagnetic induction. Radical quenching tests demonstrate that hydroxyl radicals (•OH) played a main role in the pollutant degradation. The system is of good economic and environmental benefits with a total treatment cost of about 1.015 $/m3, achieving the objective of “treating waste with waste”.

Copper regulation of PtRhRuCu nanozyme targeted boosting peroxidase-like activity for ultrasensitive smartphone-assisted colorimetric sensing of glucose

Point-of-care testing (POCT) is promising for biodetection in home healthcare due to advantages of simplicity, rapidity, low cost, portability, high sensitivity and accuracy, and object-oriented POCT platform can be developed by nanozyme-based biosensing. However, designing high-performance nanozymes with targeted regulated catalytic activity remains challenging. Herein, advanced PtRhRuCu quaternary alloy nanozymes (QANs) were rationally designed and successfully synthesized. Cu atoms induced mechanisms of hydrogen peroxide (H2O2) activation and d-band center regulation, achieving high enhancement of peroxide (POD)-like activity and inhibition of oxidase (OXD)-like activity. Inspired by this, a smartphone-assisted colorimetric platform integrated with test strips was established for glucose detection of soft drinks, with a detection limit of 0.021 mM and a recovery rate of 97.87 to 103.36 %. This work not only provides a novel path for tuning specific enzyme-like activities of metal nanozymes, but also shows the potential feasibility for rational design of POCT sensors in actual samples.

Construction of site-specific magnetic Z-scheme CdS/Fe3O4@N-doped graphene aerogel microtube/N-doped TiO2 with porous structure: enhanced catalytic performance in photo-Fenton reaction.

The development of composite photocatalysts with high charge transfer efficiency, great visible light absorption, and quick recovery has aroused the interest of many researchers. Herein, based on the hydrothermal assisted vacuum freeze drying method, CdS, Fe3O4, and N-TiO2 were, respectively, fixed in the inner, middle, and outer layers of nitrogen-doped graphene aerogel for preparation of the site-specific magnetic porous Z-scheme CdS/Fe3O4@N-doped graphene aerogel microtube/N-doped TiO2 (CdS/Fe3O4@NGAM/N-TiO2) photocatalyst. For the composite, Fe3O4@NGAM carrier with porous and tubular structure not only helps the recycle and reactants/productions mass transport in the photocatalytic process but also ensures the well-steered transfer of electrons and holes from CdS and N-TiO2 in the Z-type heterojunction system, greatly improving the separation of photogenerated carriers. Besides, Fe3O4 can also work as a Fenton catalyst to activate hydrogen peroxide which is generated in situ by CdS. Thus, the CdS/Fe3O4@NGAM/N-TiO2 composite presents excellent degradation efficiencies towards methyl orange ((MO) 98% removal rate within 50min), bisphenol A ((BPA) 96% removal rate within 50min), tetracycline hydrochloride ((TCH) 96% removal rate within 120min) and strong stabilities after 6 cycles. The free radical removal experiments show that ·O2- and ·OH are the main active substances of catalysis, which further confirms the synergistic effect of photocatalysis and Fenton catalysis.

Nitrogen-doped carbon enhances Fe0 activation for efficient tetrabromobisphenol a decontamination and its removal mechanism

Biomass derived N-doped carbon-encapsulated nano zero-valent iron (NC@Fe0) was successfully used to activate hydrogen peroxide (H2O2) for efficient oxidation of tetrabromobisphenol A (TBBPA). The as-prepared NC@Fe0 exhibited high H2O2 activation performance, with a TBBPA removal efficiency of 95.9 % and an oxidation rate constant of 0.031 min−1. The quenching experiments and electrochemical tests showed that the overall contributions of nonradical pathways were over 83.0 %, via synergistic production of singlet oxygen (1O2) and an electron transfer process (ETP). Specifically, the N group on NC@Fe0 greatly enhanced 1O2 production, while formation of surface complexes (OVs-H2O2) was responsible for the ETP mechanism. High Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometer (HPLC-Q-TOF MS/MS) and Toxicity Estimation Software Tool (T.E.S.T) clearly demonstrated that products were mainly generated via debromination and β-scission, where the products were less toxic than the parent. During practical wastewater, in both lake water and domestic wastewaters, NC@Fe0/H2O2 removed over 91.0 % of TBBPA. This study highlighted the considerable contribution of nonradicals in contaminant removal and enriched our understandings of a green activator for future environmental remediations.

Deep Oxidation of Chlorinated VOCs by Efficient Catalytic Peroxide Activation over Nanoconfined Co@NCNT Catalysts.

The catalytic removal of chlorinated VOCs (CVOCs) in gas-solid reactions usually suffers from chlorine-containing byproduct formation and catalyst deactivation. AOP wet scrubber has recently attracted ever-increasing interest in VOC treatment due to its advantages of high efficiency and no gaseous byproduct emission. Herein, the low-valence Co nanoparticles (NPs) confined in a N-doped carbon nanotube (Co@NCNT) were studied to activate peroxymonosulfate (PMS) for efficient CVOC removal in a wet scrubber. Co@NCNT exhibited unprecedented catalytic activity, recyclability, and low Co ion leakage (0.19 mg L-1) for chlorobenzene degradation in a very wide pH range (3-11). The chlorobenzene removal efficiency was kept stable above 90% over Co@NCNT, much higher than that of nonconfined Co@NCNS (45%). The low-valence Co NPs achieved a continuous electron redox cycling (Co0/Co2+ → Co3+ → Co0/Co2+) and greatly promoted the O-O bond dissociation of PMS with the least energy (0.83 eV) inside the channel of Co@NCNT to form abundant HO• and SO4•-. Thus, the deep oxidation of chlorobenzene was achieved without any biphenyl byproducts from the coupling reaction. This study provided a new avenue for designing novel nanoconfined catalysts with outstanding activity, paving the way for the deep oxidation of CVOC waste gas via AOP wet scrubber.

Degradation of sodium butylxanthate in flotation wastewater by natural pyrite via visible light-assisted advanced oxidation processes: A comprehensive study

The advanced oxidation process (AOPs) based on natural pyrite (NP) as a catalyst is a promising strategy for flotation wastewater purification. However, the slow Fe(III)/Fe(II) cycle limits the number of active sites during oxidant activation. Therefore, this work attempts to accelerate Fe(III)/Fe(II) reduction on NP surface by introducing visible light irradiation. By comparing the degradation performance of sodium butylxanthate (SBX) via various oxidants (peroxydisulfate, periodate, hydrogen peroxide, and sulfite) activation under visible light, periodate was selected as the most suitable oxidant for SBX removal. Although peroxydisulfate exhibits optimal SBX degradation in acidic environments, its failure in alkaline environments and poor reusability caused by high surface oxidation limit its application. The investigation of active species suggests that O2[Formula: see text] are the dominant active species in hydrogen peroxide and sulfite activation systems, while the electron transfer process is the dominant active species in peroxydisulfate and periodate activation systems. Electrochemistry elucidates the interaction of different oxidants on the NP surface. XPS analysis revealed that the photogenerated electrons induced by visible light irradiation accelerate the Fe(III)/Fe(II) cycle on NP surface, thereby improving the continuous activation of NP towards the oxidants. In addition, the ecotoxicity of wastewater treated by the periodate activation system is greatly reduced. This work provides a new idea towards flotation wastewater purification.

Engineering the growth and electrochemical assessments of phosphorous-doped nitrogen-based carbon nanofibers with 3D-interconnected weaving network structure for high-energy symmetric supercapacitors

The growing demand for sustainable energy sources has led to a change in attention towards developing cost-effective, high-performance energy storage devices. The construction of porous carbon network nanostructures with high surface area is complex for current-generation supercapacitors, mainly due to molecular flexibility and carbon production constraints. This work successfully produced a porous carbon nanostructure by doping phosphorous into nitrogen-based carbon nanofibers (P-doped NCNFs) utilizing a simple and controllable approach. This process entailed electrospinning diammonium hydrogen phosphate and polyacrylonitrile, subsequent high-temperature carbonization, and substantial segmented hydrogen peroxide activation processes. The P-doped NCNFs had a notable surface area of 100.69 m2 g−1, characterized by a distinct 3D-interconnected weaving network morphology. The 1 % P-doped NCNFs exhibited an exceptionally high capacitance of 265 ± 2 F g−1 when tested in a three-electrode setup at a current density of 0.5 A g−1. In addition, the constructed symmetrical supercapacitors with two identical P-doped NCNFs using a neutral Na2SO4 electrolyte exhibited remarkable electrochemical characteristics, which include a substantial capacitance of 225 ± 2 F g−1 at a current density of 0.5 A g−1, a high energy density of 30.9 Wh kg−1, an excellent Coulombic efficiency of 98.8 % over 6000 cycles, an impressive power density of 250 W kg−1, and significant capacitance retention of 85.6 %. These findings suggest that P-doped NCNFs could be excellent options for next-generation high-performance supercapacitors.

Organocatalytic activation of hydrogen peroxide: towards green and sustainable oxidations.

The advent of organocatalysis provided an additional option in every researcher's arsenal, towards the development of elegant and sustainable protocols for various organic transformations. Oxidation reactions are considered to be key in organic synthesis since oxygenated functionalities appear in many natural products. Hydrogen peroxide is categorized as a green oxidant, since its only by-product is water, offering novel opportunities for the development of green and sustainable protocols. In this review article, we intend to present recent developments in the field of the organocatalytic activation of hydrogen peroxide, providing useful insight into the applied oxidative protocols. At the same time, we will present some interesting mechanistic studies, providing information on the oxygen transfer processes.