O2 Adsorption Research Articles

Selective Generation of Reactive Oxygen Species in Photocatalytic Oxidation by Tuning Porphyrin-Based COFs' Dimensionality.

Regulating the selective generation of reactive oxygen species (ROS) is a significant challenge in the field of photocatalytic oxidation, with successful approaches still being limited. Herein, we present a strategy to selectively generate singlet oxygen (1O2) and superoxide radicals (O2•-) by tuning the dimensionality of porphyrin-based covalent organic frameworks (COFs). The transformation of COFs from three-dimensional (3D) solids to two-dimensional (2D) sheets was achieved through the reversible protonation of the imine bond. Upon irradiation, both bulk and thin-layer COF-367 can transfer energy to O2 to generate 1O2. However, thin-layer COF-367 exhibited a superior performance compared to its bulk counterpart in activating O2 to form the O2•- radicals via electron transfer. After excluding the influences of the band structure, O2 adsorption energy, and frontier orbital composition attributed to the dimensionality of the COFs, it is reasonably speculated that the variance in ROS generation arises from the differential exposure ratios of the active surfaces, leading to distinct reaction pathways between the carrier and O2. This study is the first to explore the modulation mechanism of COF dimensionality on the activation of the O2 pathway, underscoring the importance of considering COF dimensionality in photocatalytic reactions.

Developing three-dimensional hydrophobic photocatalysts to enhance mass transfer for promoting hydrogen peroxide production

Photocatalytic oxygen reduction reaction (ORR) is a promising approach for hydrogen peroxide (H2O2) production to alternative conventional anthraquinone process. However, the slow O2 diffusion and low-efficiency water oxidation reaction (WOR, limitation of protons) pathways have restricted the H2O2 production efficiency of organic photocatalysts. Therefore, a promising strategy to develop photocatalysts with three-dimensional (3D) architectures possessing high O2 diffusion, high-efficiency WOR pathway, and quick H2O2 desorption is desirable. Herein, a hydrophobic two-dimensional porous organic polymer (2D-POP) based on tetraphenylethylene (TPE) was synthesized as the building block. 3D-POPs (TPE-2 and TPE-3) were subsequently developed through the Friedel-Crafts alkylation reaction to regulate the O2 adsorption and optical properties. The 3D architectures allow O2 to diffuse into the interlayers, leading to efficient extraction of O2 from air, thus an excellent H2O2 production rate of 2.57 mmol g−1 h−1has been achieved by TPE-2 in air and without sacrificial agents, which only decreases by 4% compared to that in O2 due to a suitable specific surface area, good photoelectric properties, and excellent mass transfer of O2, H+, and H2O2. Furthermore, the H2O2 production rate of TPE-2 reaches 2.67 mmol g−1 h−1 in a triphasic system in air, which is higher than that in a traditional diphasic system, and the concentration of H2O2 reaches 1.80 mmol L−1 h−1. Additionally, by adding external Fe2+ or Fe3+ to make the utmost of photogenerated H2O2 and trigger the in-situ Fenton reaction for the formation of ·OH, TPE-2 exhibits extraordinary photodegradation efficiency toward representative organic pollutants, reaching > 99% removal within 60 min for bisphenol A and 2,4-dichlorophenoxyacetic acid with high concentrations (200 ppm).

Enhanced ORR kinetics and stability through synergy of Pt-Ni clustering and porous N-doped C/Ca aerogel support

The oxygen reduction reaction (ORR) is fundamental in numerous electrochemical energy conversion technologies, necessitating efficient catalysts to enhance reaction kinetics and reduce precious metal usage. This study focuses strategic clustering of Pt-Ni on Calcium Oxide/activated carbon (C/Ca) aerogels. Electrochemical analyses confirmed that incorporating Ni into Pt matrices significantly enhanced ORR activities with Pt25Ni75-C/Ca composition emerged as optimum. A positive shift in half-wave potential (905 mV vs. RHE) and impressive mass activity (72.50 Ag−1 at 85 V) highlight the potential of this composite as a highly effective and stable ORR catalyst. Pt-C/Ca demonstrated performance fluctuation, while Pt25Ni75-C/Ca showed remarkable stability after 40,000 cycles. Furthermore, C/Ca aerogels exhibited a significantly increased BET surface area, and the presence of Pt-Ni/pyridinic-N species on its surface C/Ca aerogel provided supplementary active sites that facilitated the adsorption and reduction of O2 during ORR.

Probing morphology-dependent PDI/g-C3N4 heterostructures for co-production of H2O2 and 2,5-diformylfuran

Perylene diimide/Carbon nitride (PDI/CN) is an excellent photocatalyst consisting of self-assembled PDI with a π-π stacking structure, and has wide applications. But the effect of PDI morphology over their photocatalytic performance has been scarcely investigated. Herein, we successfully synthesized three different morphologies of PDI, inducement formed by different organic solvents, and coupled them with CN, respectively. For simultaneous production of H2O2 and DFF, their photocatalytic activity has the order of PDI-F/CN > PDI-S/CN > PDI-B/CN. H-stacked PDI-F/CN exhibits good crystallinity, larger specific surface area, higher π-conjugation and large dipole moment, which could improve charge-carrier separation, and its activity was 4.2-fold higher than that of CN. Theoretical calculation results indicated that the PDI-F/CN heterojunction could benefit the adsorption of O2 and 5-HMF and lower the energy barrier, which is an important factor for the enhanced photocatalytic activity. This work provides a new and excellent photocatalyst for biomass oxidation.

Synergy of Ag and Interfacial Oxygen Vacancies on TiO2 for Highly Efficient Photocatalytic Production of H2O2.

Photocatalytic H2O2 production stands as a promising sustainable technology for chemical synthesis. However, rapid charge recombination and limited oxygen adsorption by photocatalysts often limit its efficiency. Herein, we demonstrate that the synergy of Ag and interfacial oxygen vacancies on TiO2 could overcome these challenges. The optimized Ag/TiO2-50 photocatalyst achieved an impressive H2O2 production rate of 12.9 mmol h-1 g-1 and maintained a steady-state concentration of 12.8 mM, significantly outperforming most TiO2-based photocatalysts documented in the literature. Detailed mechanistic studies, aided by TAS, in situ X-ray photoelectron spectroscopy (XPS), and in situ electron paramagnetic resonance (EPR) techniques, indicate that the oxygen vacancies at the Ag-TiO2 interface act as an interfacial hole trap, inducing a directional hole transfer. This, coupled with Ag acting as an electron acceptor, synergistically boosts the electron-hole separation. Additionally, the increased amount of oxygen vacancies at the Ag-TiO2 interface of Ag/TiO2-50 leads to enhanced O2 adsorption, thus contributing to its superior catalytic performance. This study provides valuable insights into interfacial traps in the charge transfer process and highlights the potential of interface regulation for achieving efficient photocatalytic conversion.

Unveiling O2 adsorption on non-metallic active site for selective photocatalytic H2O2 production

Photocatalytic oxygen reduction reaction (ORR) offers a promising pathway for sustainable hydrogen peroxide (H2O2) production but faces challenges in developing catalysts with good ORR selectivity. Herein, we report that tailoring O2 adsorption on non-metallic active sites can optimize ORR selectivity. This concept is demonstrated on three carbon nitrides with different atomic configurations: polymeric carbon nitride (PCN), lithium-poly triazine imide (Li-PTI), and sodium-poly heptazine imide (Na-PHI). Na-PHI emerges as a strong candidate for H2O2 production due to the end-on adsorption mode and suitable adsorption strength with O2. Synthesized Na-PHI, PCN, and Li-PTI are characterized, with Na-PHI showing superior light absorption, charge carrier separation, and remarkable selectivity (92 %) for two-electron ORR. Consequently, Na-PHI achieves a high H2O2 generation rate of 3.48 mmol g−1 h−1, surpassing Li-PTI and PCN by 9.2 and 33 times, respectively. This study underscores the importance of O2 adsorption on non-metallic active sites for selective photocatalytic H2O2 generation.

Effect of A-site cation doping on the catalytic oxidation of toluene over mullite catalyst GdMn2O5

Manganese-based mullite (AMn2O5) catalysts are promising for the catalytic oxidation of VOCs, with their oxidation reaction performance being tunable by modifying the composition of the A-site elements. In this work, various manganese-based mullite catalysts (Gd0.9X0.1Mn2O5, X =Sr, Ce, or Ca) with different A-site elements doping were prepared by the citric acid sol–gel method and applied to the catalytic oxidation of toluene. The activity tests indicated that the enhancement of catalytic performance by doping elements was in the order of Sr > Ce > Ca. Notably, the T90 of the Gd0.9Sr0.1Mn2O5 catalyst was 235.6 °C, a lower 37.8 °C than that of the GdMn2O5. Comprehensive characterization and density functional theory (DFT) simulations revealed that Sr doping facilitates the reduction of Mn4+ to Mn3+, increases the electron occupancy of the eg orbitals in octahedral Mn sites, and elevates the Mn-d band center, thus facilitating the adsorption and activation of O2. Additionally, the raised O-p band center caused by Sr doping enhances lattice oxygen mobility. In situ DRIFTS analysis indicated that the introduction of Sr at the A-site optimizes the toluene reaction pathway and accelerates the reaction rate. This work reveals that a simple A-site cation doping strategy can effectively regulate manganese-based mullite catalysts’ electronic structure and surface reaction activity, providing a feasible method for the large-scale preparation of manganese-based mullite catalysts with excellent catalytic performance.

Insights into transition metal encapsulated inside carbon aerogel for accelerated electro-peroxone oxidation: Activity evaluation and reactive oxygen species generation

Transition metals have critical influences on the generation of reactive oxygen species in activating O3 and H2O2, as the binary oxidant sources in electro-peroxone (EP). To evaluate the catalytic activity of different metals and reveal the reactive oxygen species generation in heterogeneous EP, series of metals encapsulated inside carbon aerogel spheres (M@CS, M=Fe, Co, Ni, Zn) were fabricated for strengthening EP. Atrazine was used as model pollutant due to its low reactivity with O3, and the abatement trends followed Co@CS > Fe@CS > Ni@CS > Zn@CS. Co@CS exhibited the superior catalytic activity with maximum metal active site utilization (1.28 × 103 min-1 mol-1 per mole Co atom sites at pH 7) and minimum electric energy consumption (0.106 kWh/m3-log). The catalytic activity of M@CS was related to the adsorption energies for O3 and H2O2 (Fe@CS > Co@CS > Ni@CS > Zn@CS) and the graphitization degree (Co@CS > Fe@CS > Ni@CS > Zn@CS). Verified by theoretical calculation and in-situ Fourier transformed infrared, the metal effectively promoted the adsorption and decomposition of O3 and H2O2 into the surface oxygen intermediates, finally generating ·OH/·O2-/1O2. The carbon layer was conducive to the reduction of internal metal, ensuring catalyst durability. Electronic paramagnetic resonance and kinetic model revealed the occurrence, ratio and transient concentration of ·OH/·O2-/1O2 in M@CS/EP. M@CS/EP showed good performance for pollutant removal in coexistence of anions, humic acid and real water. This study provides guidance for selecting the metal–carbon catalyst in heterogeneous EP.

Investigation on Be, Mg, Ca, B, Ga, C, Si, and Ge atoms doped on Al (111) surface and their effect on oxygen adsorption: A first-principle calculation

Oxygen corrosion of the aluminum alloy has a substantial impact on the durability of engineering materials and equipment. To better understand how various alloy elements affect oxygen corrosion, we used first-principle DFT method to study the role of each given dopant atom (Be, Mg, Ca, B, Ga, C, Si, and Ge) in the formation of surface oxide film on the Al (111) surface, in the case replacing a surface Al atom. Our calculations show that the electron gain or loss abilities of these alloy elements differ from that of Al metal, with Be, B, C, and Si atoms tending to penetrate into the surface, Mg, Ca, and Ga atoms protruding, and Ge atom just embedded into the Al (111) surfaces. Additionally, the type of doping element at the Al (111) surface can greatly affect the O2 absorption, predicting that Ca-doped surface absorb the least amount of oxygen, followed by Si-doped surface, with Be-, Mg-, B-, Ga-, C-, and Ge-doped surfaces showing higher O2 absorption. Based on adsorption energy (Eads) and partial density of states (PDOS) analysis, we conclude that the doped Al (111) surfaces can make O2 adsorption different owing to the difference in electronic properties of the doping atoms. These insights draw a greater knowledge of the role of alloy elements in the oxygen corrosion of Al alloys, enabling guidance for designing more corrosion-resistant materials.

Enhanced Photocatalytic Ozonation Using Modified TiO2 With Designed Nucleophilic and Electrophilic Sites.

Photocatalytic ozonation is considered to be a promising approach for the treatment of refractory organic pollutants, but the design of efficient catalyst remains a challenge. Surface modification provides a potential strategy to improve the activity of photocatalytic ozonation. In this work, density functional theory (DFT) calculations were first performed to check the interaction between O3 and TiO2-OH (surface hydroxylated TiO2) or TiO2-F (surface fluorinated TiO2), and the results suggest that TiO2-OH displays better O3 adsorption and activation than does TiO2-F, which is confirmed by experimental results. The surface hydroxyl groups greatly promote the O3 activation, which is beneficial for the generation of reactive oxygen species (ROS). Importantly, TiO2-OH displays better performance towards pollutants (such as berberine hydrochloride) removal than does TiO2-F and most reported ozonation photocatalysts. The total organic carbon (TOC) removal efficiency reaches 84.4 % within two hours. This work highlights the effect of surface hydroxylation on photocatalytic ozonation and provides ideas for the design of efficient photocatalytic ozonation catalysts.

Mesoporous Ag-K-Al2O3 catalysts prepared via a one-pot evaporation induced self-assembly approach and their application in catalytic oxidation of formaldehyde

Mesoporous Ag-Al2O3-m and Ag-K-Al2O3-m catalysts were fabricated by a one-pot technique based on an evaporation-induced self-assembly method. Among them, Ag-3 K-Al2O3-m exhibited the highest activity, achieving 100 % HCHO conversion at 40 °C. The catalyst’s performance was notably impacted by RH conditions, which showed improved activity at 30 % RH, due to the formation of active –OH groups. As the K loading increased, the aggregation of Ag particles gradually occurred. According to DFT computation, the presence of K promoted the adsorption and activation of HCHO, O2 and H2O on the catalyst surface. The superior low-temperature reducibility, adequate surface active oxygen and surface –OH groups were identified as key roles to the enhanced catalytic performance of Ag-K-Al2O3-m. Both Ag-Al2O3-m and Ag-K-Al2O3-m operated through the same oxidation mechanism for HCHO oxidation.

Ethylene glycol-assisted microwave synthesis of bismuth-rich oxychlorides photocatalysts with oxygen vacancies for efficient degradation of bisphenol A and oxidation of arsenite

The bismuth-rich strategy, which involves increasing the bismuth content within the BiOCl structure, offers an effective approach for tailoring the physicochemical and optoelectrical properties of BiOCl photocatalysts for enhanced photocatalytic performance. In this study, BiOCl, Bi12O15Cl6, and Bi12O17Cl2 were selectively synthesized using the ethylene glycol (EG)-assisted microwave irradiation method by regulating the pH of the reaction solution. Photocatalytic performance was evaluated by studying bisphenol A (BPA) degradation and arsenite (As(III)) oxidation under visible-light irradiation. The energy structures and bandgaps of the materials were tuned according to their chemical compositions, affecting their photocatalytic activity. Bi12O17Cl2 (EG-pH 9) exhibited superior photo-efficiency: 85.4 % of BPA and 97.6 % of As(III) were removed by Bi12O17Cl2 (EG-pH 9) at rates 17.7 and 18.4 times higher than those of BiOCl (EG-initial pH 3), respectively. This superior performance attributed to the synergistic effect between the bismuth-rich nature and oxygen vacancies (OVs) induced by EG, along with the presence of OH− ions in the reaction solution. The increased number of OVs in Bi12O17Cl2 led to enhanced photocurrent density and charge transfer efficiency. Trapping experiments, DMPO-ESR spin-trapping, nitroblue tetrazolium transformation, terephthalic acid photoluminescence probing, and o-tolidine oxidation experiments identified holes (h+), superoxide radicals (•O2−), superoxide radicals (•OH) and electrons (e−) as the reactive species. Density functional theory calculations further highlight the OV of Bi12O17Cl2 as the active site for O2 adsorption. This study not only developed an effective method for fabricating bismuth-rich oxychlorides with OVs but also demonstrated the potential of these photocatalysts for wastewater treatment.

Unveiling Inequality of Atoms in Ultrasmall Pt Clusters: Oxygen Adsorption Limited to the Uppermost Atomic Layer

The concept of preferential atomic and molecular adsorption site is of primary relevance in heterogeneous catalysis. In the case of ultrasmall size‐selected clusters, distinguishing the role played by each atom in a reaction is extremely challenging due to their reduced size and peculiar structures. Herein, it is revealed how the inequivalent atoms composing graphene‐supported Pt12 and Pt13 clusters behave differently in the photoinduced dissociation of O2, with only those in the uppermost layer of the clusters being involved in the reaction. In this process, the epitaxial graphene support plays a fundamental active role: its corrugation and pinning induced by the presence of the clusters are crucial for defining the preferential adsorption site on the Pt atomic agglomerates, facilitating the lateral diffusion of physisorbed oxygen at a distance that induces its selective adsorption in the topmost layer of the clusters, and inducing an inhomogeneous charge distribution within the clusters which directly affects the O2 adsorption. The inhomogeneous oxidation of the clusters is resolved by means of synchrotron‐based X‐ray photoelectron spectroscopy and supported by ab initio density functional theory calculations. The possibility to identify the active sites on Pt clusters induced by cluster–support interactions has the potential to enhance the experimentally supported design of nanocatalysts.

Efficient photocatalytic H2O2 production and green oxidation of glycerol over a SrCoO3-incorporated catalyst

Photocatalysis for H2O2 production suffers from low carrier utilization and slow reaction kinetics. Herein, a photocatalytic system supported by a SrCoO3-MoS2 (SCOS) heterojunction, which possessed a unique S-O electron transport channel, was proposed to facilitate H2O2 production under condition where glycerol served as a sacrificial agent. The SCOS heterojunction achieved a remarkable yield of 15.90 mmol g−1 h−1 H2O2 production, 3.7 times higher than the base component SCO. The construction of the heterojunction enriched the oxygen vacancies on the catalyst surface, facilitated photogenerated charge separation, and promoted the adsorption of O2, reducing the oxygen reduction reaction (ORR) energy barrier. Besides, glycerol served as a unique proton donor, efficiently captured holes to enhance H2O2 production, and generated valuable by-products including glyceric acid and dihydroxyacetone. Furthermore, SCOS exhibited excellent stability over repeated cycles with consistent H2O2 yields. This study offers an efficient photocatalytic system and demonstrates glycerol’s potential in green oxidation processes.

Inclusion Strategy for Constructing S/N Orbital Hybridization-Regulated sp3/sp2 Carbon toward Boost Electrocatalysis.

Metal-free carbon-based electrocatalysts have gained significant attention in the field of zinc-air batteries (ZABs) due to their affordability, good conductivity and chemical stability. However, unmodified carbon materials typically fall short in adsorbing and activating the substrates and intermediates involved in oxygen reduction reactions (ORR). Here, a metal-free carbon-based electrocatalyst with S atom p orbital hybrid modified N-sp3/sp2 carbon structure (C/NS) were prepared by cyclodextrins inclusion. The catalyst demonstrates impressive ORR activity (E1/2=0.885 V vs. RHE) and robust ZABs performance with a power density of 171.3 mW cm-2 and a specific capacity of 781.2 mAh g-1. Density functional theory (DFT) calculation reveals that S atom effectively regulates the charge distribution and p-band center of active site carbon atom in the N-sp3/sp2 carbon structure. This modification prompts the adsorption and dissociation of O2 and intermediates, resulting in higher reactive activity. This work provides a valuable and practical strategy for preparing cost-effective metal-free carbon-based electrocatalysts for ORR with high performance.

Sublimation Transformation Synthesis of Dual-Atom Fe Catalysts for Efficient Oxygen Reduction Reaction.

Dual-atom catalysts (DACs) have garnered significant interest due to their remarkable catalytic reactivity. However, achieving atomically precise control in the fabrication of DACs remains a major challenge. Herein, we developed a straightforward and direct sublimation transformation synthesis strategy for dual-atom Fe catalysts (Fe2/NC) by utilizing in situ generated Fe2Cl6(g) dimers from FeCl3(s). The structure of Fe2/NC was investigated by aberration-corrected transmission electron microscopy and X-ray absorption fine structure (XAFS) spectroscopy. As-obtained Fe2/NC, with a Fe-Fe distance of 0.3 nm inherited from Fe2Cl6, displayed superior oxygen reduction performance with a half-wave potential of 0.90 V (vs. RHE), surpassing commercial Pt/C catalysts, Fe single-atom catalyst (Fe1/NC), and its counterpart with a common and shorter Fe-Fe distance of ~0.25 nm (Fe2/NC-S). Density functional theory (DFT) calculations and microkinetic analysis revealed the extended Fe-Fe distance in Fe2/NC is crucial for the O2 adsorption on catalytic sites and facilitating the subsequent protonation process, thereby boosting catalytic performance. This work not only introduces a new approach for fabricating atomically precise DACs, but also offers a deeper understanding of the intermetallic distance effect on dual-site catalysis.

Interface coupling to improve O2 adsorption and accelerate charge separation for boosting photocatalytic performance of ZnO/ZnIn2S4 composite in H2O2 production and environmental remediation

The key to heterogeneous photo-Fenton technology lies in the efficient generation of hydrogen peroxide (H2O2). Herein, a newly-designed ZnO/ZnIn2S4 composite with heterostructure is synthesized. Benefiting from the formation of built-in electric field, the recombination of photoinduced electrons and holes is suppressed and interfacial charge transfer resistance is reduced. Importantly, the embedding of ZnO in ZnIn2S4 can improve the hydrophobicity and create microscopic three-phase interface, thereby boosting the capture capability for O2 and providing the convenience for the occurrence of O2 reduction reaction. More interestingly, the existence of ZnIn2S4 in the ZnO/ZnIn2S4 composite can reduce the Gibbs free energy (ΔG) of key intermediate (OOH*) formation, which will accelerate the generation of H2O2. As a result, the ZnO/ZnIn2S4 composite displays excellent performance in photocatalytic H2O2 production, and the highest yield was about 897.6 μmol/g/h within 60 min under visible light irradiation. The transfer of photoinduced carriers follows the S-scheme type mechanism. The photogenerated holes can be captured by drug residues (i.e., diclofenac sodium) to accelerate H2O2 production, while generated H2O2 can combine with Fe2+ to construct photo-Fenton system for achieving the advanced degradation of diclofenac sodium, which was mainly related to the formation of OH•. Furthermore, generated H2O2 can be applied for performing the inactivation of pathogenic bacteria. In short, current work will provide a valuable reference for future research.

Sublimation Transformation Synthesis of Dual‐Atom Fe Catalysts for Efficient Oxygen Reduction Reaction

Dual‐atom catalysts (DACs) have garnered significant interest due to their remarkable catalytic reactivity. However, achieving atomically precise control in the fabrication of DACs remains a major challenge. Herein, we developed a straightforward and direct sublimation transformation synthesis strategy for dual‐atom Fe catalysts (Fe2/NC) by utilizing in situ generated Fe2Cl6(g) dimers from FeCl3(s). The structure of Fe2/NC was investigated by aberration‐corrected transmission electron microscopy and X‐ray absorption fine structure (XAFS) spectroscopy. As‐obtained Fe2/NC, with a Fe–Fe distance of 0.3 nm inherited from Fe2Cl6, displayed superior oxygen reduction performance with a half‐wave potential of 0.90 V (vs. RHE), surpassing commercial Pt/C catalysts, Fe single‐atom catalyst (Fe1/NC), and its counterpart with a common and shorter Fe–Fe distance of ~0.25 nm (Fe2/NC‐S). Density functional theory (DFT) calculations and microkinetic analysis revealed the extended Fe–Fe distance in Fe2/NC is crucial for the O2 adsorption on catalytic sites and facilitating the subsequent protonation process, thereby boosting catalytic performance. This work not only introduces a new approach for fabricating atomically precise DACs, but also offers a deeper understanding of the intermetallic distance effect on dual‐site catalysis.

Ternary ordered L10-Pt-Co-Fe intermetallics for efficient ORR catalysis through dissociation pathway

Developing efficient and durable Pt-based electrocatalysts for oxygen reduction reaction (ORR) is critical for the practical application of fuel cells but still remains challenge at present. Here we successfully synthesized a series of ternary L10-PtCoxFe1-x (x=0.33, 0.50 and 0.67) intermetallic nanoparticles (NPs) supported on reduced graphene oxide for ORR catalysis. L10-PtCo0.50Fe0.50 exhibits the highest mass activity (MA) of 0.93 A mg−1Pt at 0.9 V (1.82 times the corresponding binary L10-PtCo intermetallics) and minimal activity loss (24.73 % loss in MA) after 30,000 potential cycles. By Density Functional Theory calculations, the excellent performance of ternary L10-PtCo0.50Fe0.50 can be ascribed to: (1) more efficient electronic structure regulation caused by dual-element driven electron transfer, which leads to more electron accumulation on Pt and weakens the over-binding of oxygen-containing species, (2) the unique two-center bridge pattern of O2 adsorption over Pt-Fe site leads to ORR proceeding via. the dissociative mechanism, avoiding the formation of OOH*.

Engineering atomic Rb-N configurations to tune radical pathways for highly selective photocatalytic H2O2 synthesis coupled with biomass valorization

Photocatalytic oxygen reduction for hydrogen peroxide (H₂O₂) synthesis presents a green and cost-effective production method. However, achieving highly selective H₂O₂ synthesis remains challenging, necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative by-products. Herein, we report for the visible light-driven simultaneous co-photocatalytic reduction of O2 to H2O2 and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride (CNRb). The optimized CNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h−1 for H2O2 generation and photooxidation rate of 3.75 mM h−1 for furfuryl alcohol to furoic acid, achieving a remarkable solar-to-chemical conversion (SCC) efficiency of up to 2.27%. Experimental characterizations and DFT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical formation. This is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2 adsorption and reinforce the capability to extract protons, thereby triggering a high selective redox product formation. This study holds great potential in precisely regulating reactive radical processes at the atomic level, thereby paving the way for efficient synthesis of H2O2 coupled with biomass valorization.