Synthesis Of Peroxide Research Articles

Enhancement of selectivity towards the synthesis of hydrogen peroxide by dimensional effect in mesoporous carbon

Efficient and selective electrocatalysts materials are currently needed for renewable energy conversion. This work studies the influence of internal channel modifications and the type of mesoporous silica that changes the electrocatalytic activities from the synthesized mesoporous carbon. Thus, MCM-41 and SBA-15 functionalized with amine (A) or diamine (D) groups and polyaniline (PANI) after pyrolysis produces derived mesoporous heteroatom-doped carbon that were evaluated as electrocatalyst in oxygen reduction reaction (ORR) for fuel cell systems. ORR can produce two types of products, allowing us to differentiate the main electrocatalytic activities of the synthesized mesoporous carbons. Therefore, the electrocatalytic results correlated the number of electrons transferred with the kind of ORR product generated. CS41/D/PANI, mesoporous carbon obtained from MCM-41 modified with diamine groups, was selective towards the production of H2O2 with 2.6 electrons transferred during the reaction while the CS41/A/PANI, mesoporous carbon obtained from MCM-41 modified with amine groups, presented high catalytic activity compared to Pt/C, leading to complete reduction of O2 to H2O. However, SBA-15 does not generate mesoporous carbons with selectivity for ORR. Then, this result is directly correlated with the influence that the mesoporous carbon suffered by the silica pore size and initial modification with amine or diamine groups. Finally, the chronoamperometry analysis demonstrated carbon materials with stability over a long period and high methanol tolerance compared with noble metals like Pt/C catalysts.

The Direct Synthesis of Hydrogen Peroxide Over Supported Pd-Based Catalysts: An Investigation into the Role of the Support and Secondary Metal Modifiers

AbstractThe direct synthesis of H2O2 from molecular H2 and O2 over Pd-based catalysts, prepared via an industrially relevant, excess chloride co-impregnation procedure is investigated. Initial studies into the well-established PdAu system demonstrated the key role of Pd: Au ratio on catalytic activity, under conditions that have previously been found to be optimal for H2O2 formation. Further investigations using the optimal Pd: Au ratio identified the role of the catalyst support in controlling particle size and Pd oxidation state and thus catalytic performance. Subsequently, with an aim to replace Au with cheaper alternatives, the alloying of Pd with more abundant secondary metals is explored. Graphical Abstract

Cu‐doped Ba0.5Sr0.5FeO3‐δ for electrochemical synthesis of hydrogen peroxide via a 2‐electron oxygen reduction reaction1

AbstractElectrochemical synthesis of hydrogen peroxide (H2O2) via a two‐electron (2e–) oxygen reduction reaction (ORR) has emerged as a sustainable synthesis route compared to the anthraquinone oxidation synthesis process. Ba0.5Sr0.5Fe(1‐x)CuxO3‐δ perovskite is a particularly interesting electrocatalyst for ORR applications owing to its doping flexibility. In this study, we use experimental and computation approaches to study Ba0.5Sr0.5FeO3‐δ with and without copper doping at the B‐site for 2e– ORR. Our electrochemical measurements in oxygen‐saturated alkaline solution show that the selectivity of perovskite electrocatalyst increases from 30% to 65% with (0.05) copper doping in the B‐site and the onset potential is decreased. Density functional theory calculations are used to unravel the role of copper in driving high activity and selectivity toward 2e– ORR. Site‐specific engineering of Ba0.5Sr0.5FeO3‐δ by copper doping in the B‐site exposed unique adsorption sites with improved activity and selectivity for H2O2 formation.

Carbonate-Induced Electrosynthesis of Hydrogen Peroxide via Two-Electron Water Oxidation.

Electrochemical synthesis of hydrogen peroxide (H2 O2 ), via the two-electron water oxidation reaction (2e- WOR), is an attractive method for the sustainable production of valuable chemicals in place of oxygen during water electrolysis. While the majority of 2e- WOR studies have focussed on electrocatalyst design, little research has been carried out on the selection of the supporting electrolyte. In this work, we investigate the impact of potassium carbonate (K2 CO3 ) electrolytes, and their key properties, on H2 O2 production. We found that at electrolyte pH values (>9.5) where the carbonate anion (CO3 2- ) was prevalent in the mixture, a 26.5 % increase in the Faraday efficiency (%FE) for H2 O2 production was achieved, compared to bicarbonate (HCO3 - ) dominant solutions. Utilising boron-doped diamond (BDD) in highly concentrated K2 CO3 solutions, current densities of up to 511 mA cm-2 (in 4 m) and %FEs of 91.5 % (in 5 m) could be attained. The results presented in this work highlight the influence of CO3 2- on electrochemical H2 O2 generation via the 2e- WOR and provide novel pathways to produce desirable commodities at the anode during electrochemical water splitting.

Conversion of CO2 to defective porous carbons in one electro-redox cycle for boosting electrocatalytic H2O2 production

Conversion of CO2 to catalytically active carbons for electrochemical synthesis of hydroxide peroxide (H2O2) is highly desirable to replace the energy-intensive anthraquinone process, and achieve carbon utilization and emission reduction. Here, we develop an electrochemical reduction-reoxidation strategy in the in-situ conversion of absorbed CO2 to defective porous carbons (DPCs) for boosting H2O2 production. By rationally varying oxidation conditions, hole and edge defects were controllably created on CO2-derived carbons. Moreover, the defects dramatically enhanced the activity and selectivity toward the 2e- oxygen reduction reaction (ORR). DPC0.5–5 obtained by electro-oxidizing the CO2-derived carbon has edge and hole defects, delivering the H2O2 selectivity greater than 90%. By means of density functional theory calculations, the essential role of defects is demonstrated, and the types of defects with high activity are identified. The approach presented here not only sheds light on the value-added utilization of CO2, but also develops the defect engineering of carbon materials.

Carbon-Encapsulated Cobalt Phosphide Catalyst for Efficient Electrochemical Synthesis of Hydrogen Peroxide

Metal phosphides with high electronic conductivity are recognized as promising electrocatalyst for oxygen reduction reaction (ORR). Herein, we report a family of cobalt phosphides (CoP, CoP2, and CoP/CoP2) encapsulated in thin carbon layer as two-electron (2e-) ORR electrocatalysts for H2O2 production. Benefiting from the regulation of cobalt phosphide, CoP/CoP2@NPC exhibited the highest H2O2 yield among the three types of cobalt phosphides studied, with a high H2O2 selectivity (>90%) over a potential ranging from 0.2 to 0.7 V vs the reversible hydrogen electrode. Continuous generation of H2O2 is achieved at an outstanding rate of 1.93 mol with a Faraday efficiency of 83%.

N, O-coupling towards the selectively electrochemical production of H2O2

Hydrogen peroxide (H2O2) synthesis generally involves the energy-intensive anthraquinone process. Alternatively, electrochemical synthesis provides a green, economical, and environmentally friendly route to prepare H2O2 via the two-electron oxygen reduction reaction, but this process requires efficient catalysts with high activity and selectivity simultaneously. Here, we report an N, O co-doped carbon xerogel-based electrocatalyst (NO-CX) prepared by a simple and economical method. The NO-CX catalyst exhibits a high H2O2 selectivity over 90% in a potential range of 0.2–0.6 V and a high H2O2 production rate of 1410 mmol gcat−1 h−1. The density functional theory calculations demonstrate that the coupling effect between N and O can effectively induce the redistribution of surface charge and the edge carbon atom adjacent to an ether group and a graphite nitrogen atom is the active site. This work provides a straightforward and low-cost process to produce highly selective H2O2 catalysts, which is in place for the expansion of electrocatalytic synthesis of useful chemicals.

Activated Ni-based metal–organic framework catalyst with well-defined structure for electrosynthesis of hydrogen peroxide

Catalyst with well-defined active sites and highly ordered mesoporous structure is of significant importance for electrocatalytic synthesis of hydrogen peroxide (H2O2) by a two-electron oxygen reduction reaction (ORR). Herein, we present a Ni-based MOF two-electron ORR electrocatalyst derived from zeolitic imidazolate framework-8 (ZIF-8) for H2O2 production. The partial substitution of Zn in ZIF-8 with Ni (MOF Ni-250) affords a favorable two-electron ORR catalytic performance, where the elemental Ni serves as an excellent active site. In addition, the catalytic performance of the catalyst is further enhanced by calcination treatment of MOF Ni-250 under 300 ℃ (c-MOF Ni-250), which removes the crystal water and other small molecules within MOF, thus exposing the active sites and transfer channel of reaction species in catalyst layer without structure destruction. The optimized c-MOF Ni-250 exhibits an excellent H2O2 selectivity of 95% and a high H2O2 production rate of 0.51 mol·gcat.-1·h−1 at 0.37 V (vs. RHE) in 0.1 M KOH. The acitve sites of Ni atom is futher confirmed by using density functional theory (DFT) calculations. This finding demonstrates that the as-developed catalyst has a great potential in electrocatalytic synthesis of H2O2 in practical applications.

Synergistic Electronic and Pore Structure Modulation in Open Carbon Nanocages Enabling Efficient Electrocatalytic Production of H2O2 in Acidic Medium

AbstractElectrochemical synthesis of hydrogen peroxide (H2O2) through 2e– oxygen reduction reaction is an effective approach to replace anthraquinone process. However, most reported electrocatalysts work effectively in alkaline medium in which H2O2 will easily decompose into water. It is still of great challenge to develop cost‐effective electrocatalysts with high activity and selectivity for electrocatalytic H2O2 production in acidic media. Herein, it is first theoretically demonstrated that the adsorption energy of OOH* intermediate on carbon can be optimized by embedding Co nanoparticles (Co NPs) and tuning oxygen‐containing functional groups, ensuring high activity and selectivity. Guided by density functional theory calculations, highly porous open carbon nanocages with embedded Co NPs are designed and synthesized by template‐engaged method. The pyrolysis temperature can effectively modulate the electronic and pore structure of carbon nanocages. Impressively, the optimized carbon nanocages synthesized at 700 °C (P‐Co@C‐700) with highest percentage of –C–O–C group and defects, largest specific surface area (1351 m2 g–1), and mesoporous structure exhibit high selectivity up to 94% toward H2O2 production in 0.1 m HClO4. Furthermore, the P‐Co@C‐700 nanocages display promising application for efficient electro‐Fenton degradation of model organic pollutant.

SnO2-supported single metal atoms: a bifunctional catalyst for the electrochemical synthesis of H2O2

SnO2 supported single metal atoms offer unique bifunctional catalyst materials for electrochemical synthesis of hydrogen peroxide via 2e-ORR and 2e-WOR.

Trace Pt Atoms as Electronic Promoters in Pd Clusters for Direct Synthesis of Hydrogen Peroxide

Trace Pt Atoms as Electronic Promoters in Pd Clusters for Direct Synthesis of Hydrogen Peroxide

Synthesis and performance of PdMulti@HCS catalysts with Pd nanoparticles partially embedded in the inner wall of hollow carbon spheres for the direct synthesis of hydrogen peroxide from hydrogen and oxygen

PdMulti@HCS catalysts ensure the maximum exposure of Pd active sites and optimal transfer and diffusion ability for H2O2 synthesis.

Synergistic effect of doped nitrogen and oxygen-containing functional groups on electrochemical synthesis of hydrogen peroxide

A modified carbon material with N doping and oxygen-containing functional groups was prepared by a simple method, and the synergistic effect of the two greatly improved the performance of electrocatalytic production of H2O2.

Водорастворимое производное фуллерена С70 как регулятор уровня активных форм кислорода в культивируемых клетках человека

Fullerene derivatives of C60 and C70 are being investigated as potential tools for drug delivery to the body. Additionally, these compounds have the ability to effectively bind reactive oxygen species (ROS) in solutions and can be used as radioprotectors and antioxidants. However, a study of water-soluble C60 fullerene previously showed that this compound is able not only to block ROS, but also to induce secondary oxidative stress associated with cell response to a significant decrease in ROS levels. In order to further analyse the response of human cells to the presence of fullerene in the medium, we investigated the effect of a water-soluble C70 fullerene derivative on cultured human skin fibroblasts. С70 fullerene in a non-toxic concentration causes transient oxidative stress, which manifested itself in a short-term increase in the cellular DNA oxidation level. Stress occurs 3 hours after fullerene-induced decrease in the antioxidant response gene NRF2 activity and an increase in the activity of the NOX4 gene, which encodes an enzyme catalysing hydrogen peroxide synthesis. 24 hours later, the level of DNA oxidation decreases to the control values. It is suggested that fullerenes can be used not only as antioxidants, but also as potential inducers of an adaptive response that increases cell survival under negative environmental influences.

Interfacial Engineering of Vertically-Stacked Graphene/H-Bn Heterostructure as an Efficient Electrocatalyst for Hydrogen Peroxide Synthesis

Interfacial Engineering of Vertically-Stacked Graphene/H-Bn Heterostructure as an Efficient Electrocatalyst for Hydrogen Peroxide Synthesis

Photocatalysis Coupling Hydrogen Peroxide Synthesis and On-Site Radical Transform for Tetracycline Degradation

Photocatalysis Coupling Hydrogen Peroxide Synthesis and On-Site Radical Transform for Tetracycline Degradation

Electrochemical Hydrogen Peroxide Synthesis from Selective Oxygen Reduction over Metal Selenide Catalysts.

Se-based nanoalloys as an emerging class of metal chalcogenide with tunable crystalline structure, component distribution, and electronic structure have attracted considerable interest in renewable energy conversion and utilization. In this Letter, we report a series of nanosized M-Se catalysts (M = Cu, Ni, Co) as prepared from laser ablation method and screen their electrocatalytic performance for onsite H2O2 generation from selective oxygen reduction reaction (ORR) in alkaline media. A flexible control on 2e-/4e- ORR pathway has been achieved by engineering the alloying component. Moreover, through a feedback loop between theory and experiment an optimized scaling relationship between oxygenated ORR intermediates has been discovered on cubic Cu7.2Se4 nanocrystals, that is, the ensemble effect of isolated Cu component destabilizes O* binding while the ligand effect of Se to Cu fine-tunes the binding strength of OOH*, leading to a superb H2O2 selectivity above 90% over a wide potential window even after 1400 potential cycles.

Direct Hydrogen Peroxide Synthesis on a Sn-doped CuWO4/Sn Anode and an Air-Breathing Cathode

Direct Hydrogen Peroxide Synthesis on a Sn-doped CuWO₄/Sn Anode and an Air-Breathing Cathode

Continuous-flow reactor setup for operando x-ray absorption spectroscopy of high pressure heterogeneous liquid-solid catalytic processes.

A continuous-flow reactor and a continuous-flow setup compatible with operando x-ray absorption spectroscopy (XAS) were designed for safely studying liquid-phase reactions on solid high atomic number transition metal catalysts (e.g., Au, Pd, and Pt) under pressures up to 100 bars with temperatures up to 100°C. The reactor has a stainless-steel body, 2mm thick polyether ether ketone (PEEK) x-ray windows, and a low internal volume of 0.31 ml. The rectangular chamber (6 × 5 × 1 mm3) between the PEEK x-ray windows allows us to perform XAS studies of packed beds or monoliths in the transmission mode at any position in the cell over a length of 60mm. A 146° wide-angle beam access also allows recording complementary x-ray fluorescence or x-ray diffraction signals. The setup was engineered to continuously feed a single-phase liquid flow saturated with one or more gaseous reactants to the liquid-solid XAS reactor containing no free gas phase for enhanced process safety and sample homogeneity. The proof of concept for the continuous-flow XAS cell and high-pressure setup was provided by operando XAS measurements during the direct synthesis of hydrogen peroxide at room temperature and 40 bars using a 35 ± 5 mg catalyst (1 wt. % Pd/TiO2) and inline near-infrared spectroscopy. The experiments prove that the system is well suited to follow the reaction in the liquid phase while recording high-quality XAS data, paving the way for detailed studies on the catalyst structure and structure-activity relationships.

Bias-free synthesis of hydrogen peroxide from photo-driven oxygen reduction reaction using N-doped γ-graphyne catalyst

It is an ideal route to generate hydrogen peroxide (H2O2) via selective 2e- ORR powered directly by sunlight. In this work, we synthesized a metal-free N-doped γ-graphyne catalyst and wired it with n-type semiconductor photoanodes. The introduction of sunlight could lower the onset bias of oxygen reduction reaction (ORR) up to 0.32 V and H2O2 was steadily produced without any sacrificial agents and bias. The 2e- ORR selectivity of N-doped γ-graphyne catalyst was bias dependent, and it reached about 74% at 0 bias in 0.1 mol·L−1 KOH. Theoretical calculations showed that in-situ pyridinic-N in N-doped γ-graphyne acted as the active site for ORR, accelerating the rate-determining step of proton abstraction. The H2O2 yield reached as high as 7.47 mmol·h−1g−1, outperformed the reported traditional photocatalytic syntheses of H2O2.