Electronic Rearrangement Research Articles

Electronic structure modulation and peroxymonosulfate activation mechanism of N-doped MnCo2O4: A study on the efficient catalytic degradation of sulfamethoxazole

In this study, a nitrogen-doped MnCo2O4 composite material (nN-MCO) was successfully synthesized via a urea-assisted thermal treatment method and applied for the activation of peroxymonosulfate (PMS) to degrade sulfamethoxazole (SMX). By introducing metal-N (M−N) bonds, the concentration of oxygen vacancies on the catalyst surface and its electron transfer capability with PMS were significantly enhanced. Experimental characterizations demonstrated that nitrogen doping not only strengthened the covalency of the metal-O (M−O) bonds but also facilitated the formation of electron-rich metal sites through electronic rearrangement, further improving the adsorption and activation of PMS. The 2 N-MCO catalyst successfully degraded 98.0 % of SMX within 5 min and maintained a removal efficiency of 85.0 % after four consecutive cycles. The study revealed that 1O2, SO4−, OH and O2− were all involved in the degradation of SMX, with 1O2 identified as the dominant reactive oxygen species. This work presents a simple and effective nitrogen-doping strategy for surface modification of spinel-based catalysts, enhancing the MnCo2O4 composite’s electronic structure, strengthening metal–oxygen bonds, and creating electron-rich sites. These modifications promote oxygen vacancies, improve electron transfer, and enable efficient reactive oxygen species (ROS) generation, offering valuable insights and theoretical support for PMS-based oxidation processes in pollutant treatment.

Interfacial charge engineering of Cu-BTC derived octahedron-like CuS–C@SnO2 p-n heterojunction for boosting energy storage performance

Constructing unique interfaces is a reliable strategy for improving charge transfer kinetics of electrode materials and thus enhances their energy storage. Therefore, in this work, by using an ortho-octahedral Cu-BTC (Tricopper; benzene-1,3,5-tricarboxylate) to derive CuS and further anchoring SnO2 nanoparticles on its surface, a CuS–C@SnO2 p-n heterojunction with an octahedron-like structure is constructed. Benefiting from the joint influence of the novel structure and built-in electric field produced by the CuS–C@SnO2 p-n heterojunction, the CuS–C@SnO2 electrode shows a specific capacitance of 589.25 F g−1 at 1 A g−1 and an excellent rate capacity of 81.4% at 10 A g−1. Particularly, the packaged CuS–C@SnO2//AC asymmetric supercapacitor (ASC) represents a high energy density of 50.79 Wh kg−1 at a power density of 800.01 W kg−1 and an outstanding capacitance retention of 86.7% after 10000 cycles. In addition, by using density functional theory (DFT) calculations, we further confirm that CuS–C@SnO2 p-n heterojunction has a satisfactory adsorption capacity for OH− and an accelerated transfer for free electrons by the electron rearrangements at the interface, which are beneficial for CuS–C@SnO2 to enhance its storage capacity. This work provides an effective strategy for designing efficient energy storage devices.

The Investigation of Fe─F Bond Chemistry on Structural Stability for Highly Durable Layered Na2FePO4F Cathode

AbstractLayered iron (Fe) ‐based fluorophosphates, Na2FePO4F (NFPF) stands for a cost‐effective and voltage‐advantageous cathode material for sodium‐ion batteries. Nevertheless, the lack of stability imposes constraints on its development and the decay mechanism remains shrouded in ambiguity. Herein, this work proposes the breakup of Fe─F bond in octahedral dimer accountable for the dissolution of redox centers and the formation of electrochemically inert phase, ultimately leading to the deterioration of electrochemical stability. To verify and address this, Boron (B) atoms situated in interstitial positions of PO4 tetrahedra appearing trigonal BO3 can be specifically targeted to enhance bond covalency and tailor electronic rearrangements at Fe─F bonds, thus stabilizing the octahedral dimer structure. This also facilitates rapid Na+ diffusion dynamics and accelerated electronic conductivity. As expected, NFPF‐B exhibits an ultra‐high discharge specific capacity (118.34 mAh g−1 at 0.1C) and excellent long‐term durability (capacity retention of 91.9% after 1000 cycles). The stability of the octahedra dimer is underscored by minimal volume change (2.9%) within the two‐stage biphase reaction of sodium storage mechanism. This work elucidates the enduring degradation mechanism of NFPF from octahedral dimers and offer theoretical guidance for Fe‐based cathode materials with prolonged stability.

Quaternary functional semiconductor device-based temperature sensors for low and high temperatures (LTs, HTs)

Abstract The Al-(Zn:Cd:Ni:TiO2)-pSi diodes with a ratio of 4;2;2;2 were fabricated and their possible current transport mechanisms (CTMs) were investigated between 80–380 K and ±4.5 V range using current–voltage (IV) measurements. The saturation-current (Is), quality/ideality factor (n), and barrier-height (BH)/(Φ bo) values of the didoes were calculated from the forward-bias ln(IF)-VF curve as function of temperature. While the value of BH is increased with temperature, n value is decreased with increasing temperature. Non-linear behavior was observed in the Arrhenius or Richardson plot (RP) (ln(Io/T2) versus q/kT) at low temperatures (LTs). Also, the Richardson- constant (A*) calculated from the linear part of this plot is quite lesser than its theoretical- value (=32 A.(cm.K)−2 for p-Si), and high values of n at LTs show an evident deviated from thermionic-emission (TE) theory. To explain this case; both the nkT/q-kT/q, Φ bo and n versus q/2kT curves were plotted to determine the other possible-CTMs and they show that both the tunneling and Double Gaussian - distribution (DGD) are more effective rather than TE. The obtained A* value from the modified RP by using the standard deviation from Φ bo-q/2kT plot is closer to its theoretical value. The energy-dependent curve of interface states or traps (Nss) was calculated from the IF-VF characteristics by considering the voltage dependence of the BH and n for the studied temperature range and they generally decline with increase in temperature due to the rearrangement and structure of electrons at traps under the influence of temperature. All these results show that the fabricated The obtained results suggest that the fabricated Al-(ZnCdNiTiO2)-pSi diode can be used as a temperature - sensor in low and high temperature applications.

Interface-Engineered CuxO@Bi2MoO6 Heterojunctions to Inhibit Piezoelectric Screening Effect and Promote Double-Nanozyme Catalysis for Antibacterial Treatment.

Sonodynamic therapy is confronted with the low acoustic efficiency of sonosensitizers, and nanozymes are accompanied by intrinsic low catalytic activity. Herein, to increase the piezopotential of N-type piezoelectric semiconductors, the P-N heterojunction is designed to inhibit the piezoelectric screening effect (PSE) and increase electron utilization efficiency to enhance nanozyme activity. P-type CuxO nanoparticles are in situ grown on N-type piezoelectric Bi2MoO6 (BMO) nanoflakes (NFs) to construct heterostructured CuxO@BMO by interface engineering. CuxO deposition leads to lattice distortion of BMO NFs to improve piezoelectric response, and the strong interface electric field (IEF) suppresses PSE and increases piezopotential. The nonlocal piezopotential, local IEF, and glutathione (GSH) inoculation enhances electron-hole separation and increases peroxidase (POD)-like activity of BMO and GSH oxidase (GSHOx)-like activity of CuxO with high selectivity. The heterojunction formation causes the transfer and rearrangement of interface electrons, and the increased piezopotential accelerates electron transfer at interfaces with bacteria, thus increasing the production of reactive oxidative species and interfering with adenosine triphosphate synthesis. The heterostructured nanozymes produce abundant intracellular ·OH and achieve 4log magnitude reductions in viable bacteria and effective biofilm dispersion. This study elucidates integral mechanisms of nanozyme and acoustic catalysis and opens up a new way to synergize high piezopotential and nanozyme-catalyzed therapy.

Molecular Evidence for the Axial Coordination Effect of Atomic Iodine on Fe‐N4 Sites in Oxygen Reduction Reaction

AbstractWe present a molecular‐scale investigation of the axial coordination effect of atomic iodine on Fe‐N4 sites in the oxygen reduction reaction (ORR) by electrochemical scanning tunneling microscopy (ECSTM). A well‐defined model catalytic system with explicit and uniform iodine‐coordinated Fe‐N4 sites was constructed facilely by the self‐assembly of iron(II) phthalocyanine (FePc) on an I‐modified Au(111) surface. The electrocatalytic activity of FePc for the ORR shows notable enhancement with axial iodine ligands. The modulation of the electronic structure of Fe sites to evoke a higher spin configuration by axial iodine was evidenced. The interaction strength between oxygen‐containing species and active centers becomes weaker due to the presence of iodine ligands, and the reaction is thermodynamically preferable. Furthermore, the reaction dynamics of FePc on I/Au(111) were explicitly determined via in situ ECSTM potential pulse experiments. In contrast, axial atomic iodine was found inefficacious for improving the activity of Co‐N4 sites, and electron rearrangement was found to be marginal, demonstrating that adequate interactions between axial ligands and metal sites for optimizing electronic structures and catalytic behaviors are prerequisites for the impactful role of axial ligands.

Dual polarization in CoMoO4-NiMoO4 heterojunction boosted electrochemical charge storage

Binary transition metal oxides (BTMOs) stand out as a focal point due to their distinctive electrochemical properties. However, they encounter challenges like low conductivity and limited active sites. To tackle these obstacles, we have meticulously designed a CoMoO4-NiMoO4 (CMNM) heterostructure featuring significant compressive-tensile strain. This design facilitates the robust integration of CoMoO4 (CM) and NiMoO4 (NM), initiating interfacial polarization, and establishing a built-in electric field (BIEF) that significantly enhances electron transfer between the phases. Moreover, the strain serves as a driving force for the electric field, promoting the rearrangement of interface electrons and further boosting interfacial polarization. This avant-garde approach propels the CMNM electrode to achieve a remarkable specific capacity of 530.45 C g−1 at 1 A g−1, maintaining 327 C g−1 even at 10 A g−1, thus showcasing a superior rate capability. Furthermore, an asymmetric supercapacitor employing CMNM as the positive and FeOOH as the negative achieves a high energy density of 78.9 Wh kg−1 at a power density of 927.02 W kg−1. Our methodology, leveraging heterostructures coupled with the interfacial strain tactics, paves a novel avenue for high-performance supercapacitors.

On the link between the reaction force constant and conceptual DFT.

The reaction force constant ( ), introduced by Professor Alejandro Toro-Labbé, plays a pivotal role in characterizing the reaction pathway by assessing the curvature of the potential energy profile along the intrinsic reaction coordinate. This study establishes a novel link between and the reactivity descriptors of conceptual density functional theory (c-DFT). Specifically, we derive expressions that relate the reaction force constant to nuclear softness and variations in chemical potential. Our findings indicate that regions of the reaction pathway where is negative match with significant electronic structure rearrangements, while positive regions match mostly with geometric rearrangements. This correlation between and c-DFT reactivity descriptors enhances our understanding of the underlying forces driving chemical reactions and offers new perspectives for analyzing reaction mechanisms. The internal reaction path for the proton transfer in SNOH, chemical potential, and nuclear softness were computed using DFT with B3LYP exchange-correlation functional and 6-311++G(d,2p) basis set.

CFs-supported La-BiOIO3/Bi2O3 heterostructures via in situ growth strategies for efficiently removing diclofenac: Fermi level modulation, intermediates identification and radical mechanism

The charge transfer efficiency and the recyclability were still the potential factors limiting the widespread application of photocatalysts for pollutant removal. Herein, a novel design perspective for BiOIO3-based S-scheme heterojunction (La-BiOIO3/Bi2O3) with modulated Fermi level and enhanced internal electric field was proposed by in situ liquid-phase growth strategy. Meanwhile, the CFs@La-BiOIO3/Bi2O3 catalysts with high stability and easy recyclability were assembled based on industrial carbon fiber cloths, which can achieve efficiently photocatalytic removal of diclofenac (DCF, 95.5 %, 20 min) and bisphenol A (BPA, 100 %, 30 min) under simulated sunlight irradiation. The photocatalytic degradation rates of DCF were 52.8 and 12.4 times that of pure BiOIO3 and Bi2O3, respectively. The high specific surface area (39.74 m2·g−1) and suitable bandgap structure (2.74 eV) also demonstrated the excellence of the CFs@La-BiOIO3/Bi2O3 degradation system. Verification of heteroatom-driven electron rearrangement and charge migration route in heterostructure was performed through XPS analysis and Mott-Schottky experiments. Gaussian calculations, LC-MS, and toxicity assessments demonstrated that reactive oxygen species (ROS) such as ·O2− and ·OH selectively attacked the electronic groups of DCF and its intermediates, which combined with holes (h+) retained in the valence bands of Bi2O3 to synergistically achieve efficient degradation and detoxification of DCF. Finally, the charge migration mechanism for the photocatalytic elimination of DCF over CFs@La-BiOIO3/Bi2O3 photocatalyst was proposed. Similar studies can be extended to other structures capable of achieving rational Fermi level modulation and synchronous carrier introduction for the remediation of polluted waters, providing novel perspectives for improving photocatalytic driving capacity.

Upcycling polystyrene microplastics to Fe/Mo-doped sponge-carbon: Mo5+ enhanced electron transfer for boosting Fenton-like performance

The rate-limiting steps of promoting the conversion of Fe3+ to Fe2+ in Fenton-like systems are crucial for achieving efficient degradation of organic contaminants in aquatic environments. Herein, a novel magnetic Fe/Mo bimetallic doped sponge carbon (Fe/Mo-N-C) derived from polystyrene microplastics was successfully synthesized and the presence of metastable Mo5+ remarkably synergized the electron transfer of Fe2+ in internal microenvironment. In the Fe/Mo-N-C activating peroxymonosulfate (PMS) system, Mo5+ boosted the oxidation of Fe2+, and the conversion of Mo4+/Mo6+ accelerated the restoration of Fe2+ from Fe3+, resulting in nearly 100 % of 17α-ethinylestradiol (EE2) degradation with the kinetic rate constant of 0.343 min−1, which was 8.1 times faster than that of Fe-N-C. Moreover, Fe/Mo-N-C possessed excellent resistance to interference from various coexisting anions (especially chloride, sulfate, and nitrate ions up to 500 mM), natural organic matter, nano-plastics, and different water matrices. Density functional theory analysis demonstrated that Mo centers regulated the electron rearrangement of the Fe 3d orbital, enhancing the activation performance of Fe/Mo-N-C towards PMS. This study lays the groundwork for understanding the mechanism of metastable Mo, which holds significant importance for the up-recycling of polyethylene plastics and environmental remediation.

Identifying the dynamic behaviors in complete reconstruction of Co-based complex precatalysts during electrocatalytic oxygen evolution

Transition metal-based nanomaterials have emerged as promising electrocatalysts for oxygen evolution reaction (OER). Considerable research efforts have shown that self-reconstruction occurs on these nanomaterials under operating conditions of OER process. However, most of them undergo incomplete reconstruction with limited thickness of reconstruction layer, leading to low component utilization and arduous exploration of real catalytic mechanism. Herein, we identify the dynamic behaviors in complete reconstruction of Co-based complexes during OER. The hollow phytic acid (PA) cross-linked CoFe-based complex nanoboxes with porous nanowalls are designed because of their good electrolyte penetration and mass transport ability, in favor of the fast and complete reconstruction. A series of experiment characterizations demonstrate that the reconstruction process includes the fast substitution of PA by OH− to form Co(Fe)(OH)x and subsequent potential-driven oxidation to Co(Fe)OOH. The obtained CoFeOOH delivers a low overpotential of 290 mV at a current density of 10 mA cm−2 and a long-term stability. The experiment results together with theory calculations reveal that the Fe incorporation can result in the electron rearrangement of reconstructed CoFeOOH and optimization of their electronic structure, accounting for the enhanced OER activity. The work provides new insights into complete reconstruction of metal-based complexes during OER and offers guidelines for rational design of high-performance electrocatalysts.

Exploration of DNA nucleotide adsorption on GeTe monolayer through DFT analysis

DNA nucleobase sensors provide crucial information for diagnosing diseases, analyzing genetics, and advancing biological research by detecting and identifying DNA sequences in real-time. This research examined how GeTe monolayer interact with DNA nucleobases through adsorption. The adsorption strengths of the four bases on the adsorbent surface followed the order of G > C > T > A. Analysis of electronic properties indicated that the interaction between nucleobases and GeTe primarily involves physical adsorption. Additionally, higher adsorption energies led to greater rearrangement of surface electrons and changes in the adsorbent's potential barrier, resulting in significant variations in the work function (WF) value. The desorption times at 498K were A (0.02 h), G (15.8 h), C (0.72 h), and T (0.43 h), indicating the potential of GeTe as a reusable material for nucleobase sensors. We can amplify the adsorption strength (30 %–45 %) and improve the discrimination between nucleobases (208 %–808 %) by employing solvents possessing higher dielectric constants. Comparisons with recent research validated the superior adsorption performance and selectivity of the material used in this study, highlighting the promising application of the GeTe monolayer in nucleobase sequencing technology.

Breakthrough in CO2 Electroreduction to Multi-Carbon Products at Ampere-Level Enabled by Active Sites Engineering.

Efficient production of value-added chemicals with high selectivity from CO2 electroreduction at industrial-level current density is highly demanded, yet remains a big challenge. In a recent issue of Angewandte Chemie, Han and colleagues have elegantly increased the Faradaic efficiency (FE) of multi-carbon (C2+) products to over 70 % at amperes level (1.4 A cm-2) by engineering the active sites for the key reactions involved in the CO2 electroreduction. In this study, the highly dispersed Pd atoms have two unique functions: active sites for water dissociation and to induce the electron rearrangement of the surrounding Cu atoms to form new active sites for CO conversion, while the Cu far from Pd are the active sites for efficient CO2 conversion to CO, the synergistic functions of these three active sites result in high FE and yields of C2+ products at industrial-level current density. This research is a remarkable step forward in the methodology for developing efficient and durable catalysts for CO2 electroreduction and beyond.

Breakthrough in CO2 Electroreduction to Multi‐Carbon Products at Ampere‐Level Enabled by Active Sites Engineering

AbstractEfficient production of value‐added chemicals with high selectivity from CO2 electroreduction at industrial‐level current density is highly demanded, yet remains a big challenge. In a recent issue of Angewandte Chemie, Han and colleagues have elegantly increased the Faradaic efficiency (FE) of multi‐carbon (C2+) products to over 70 % at amperes level (1.4 A cm−2) by engineering the active sites for the key reactions involved in the CO2 electroreduction. In this study, the highly dispersed Pd atoms have two unique functions: active sites for water dissociation and to induce the electron rearrangement of the surrounding Cu atoms to form new active sites for CO conversion, while the Cu far from Pd are the active sites for efficient CO2 conversion to CO, the synergistic functions of these three active sites result in high FE and yields of C2+ products at industrial‐level current density. This research is a remarkable step forward in the methodology for developing efficient and durable catalysts for CO2 electroreduction and beyond.

Effect of the cyano group in the HAVA mechanism for PAHs formation: a reaction force analysis for the reaction between benzonitrile (C6H5CN) and vinylacetylene

ABSTRACT Due to the importance and fascination that arises from processes involving Polycyclic Aromatic Hydrocarbon (PAHs) in the interstellar medium (ISM), in this work quantum calculations were used to study the HAVA mechanism (Hydrogen Abstraction Vinylacetylene Addition) involved in the PAHs formation from the benzonitrile (${\rm C_6H_5CN}$), molecule recently discovered in the ISM, and vinylacetylene (${\rm C_4H_4}$). The reaction force analysis was used to obtain information about the mechanisms in terms of structural and electronic rearrangements presents in the formation of naphthalene, 1-naphthonitrile, 2-naphthonitrile, and 3-ethynylisoquinoline. Due to the presence of the cyano group on the aromatic ring for the formation of 1-naphthonitrile and 2-naphthonitrile, these reactions: (a) follow the HAVA mechanism, showing the same structural nature of the submerged energy barriers and (b) result consistent with the fact that both molecules have recently been found in TMC-1, where benzonitrile and vinylacetylene are also present. The mesomeric and inductive effect of the cyano group on the aromatic ring contributes to lowering the energy barrier when the radical is in the ortho position on the aromatic ring with respect to the cyano group. This decrease contributes greatly to the work of electronic reordering. Although the formation of 3-ethynylisoquinoline (N-Heterocycle) does not follow the HAVA mechanism and involves positive barriers at the conditions of TMC-1, important astrochemical and astrobiological implications can be derived from this result, since N-containing heterocycles, have been detected in carbonaceous chondrites would be providing interesting connection between chemistry in space and the origin of life on Earth.

Refining Mn(III) Active Sites in MnO2-Based Self-Assembled Electrodes Via Oxygen Vacancy Induction to Enhance Oxygen Reaction Performance in Zinc-Air Batteries

Rechargeable zinc-air batteries are considered as a promising candidate for next-generation electrochemical energy conversion devices due to their safety, low cost, and high theoretical capacity/ energy density. Over the past few decades, α-MnO2-based electrodes have demonstrated their excellent performance and competitiveness in oxygen catalytic reactions. (1) According to eg filling theory, Mn(III) (t2g3eg1) sites in [MnO6] octahedral unit deliver superior bifunctional activity compared to Mn(II) (t2g3eg2) and Mn(IV) (t2g3eg0) sites.(2) However, the presence of unpaired single electrons of the Mn(III) site leads to low thermodynamic stability. Introducing oxygen vacancies to promote the electron rearrangement of the [MnO6] unit is a promising approach for enhancing the durability of Mn(III) active sites. Herein, we construct an oxygen-vacancy-enhanced MnO2-based electrode via a self-assembly process (NiCo2O4-MnO2@Ni foam). The intrinsic oxygen catalytic activity of NiCo2O4-MnO2@Ni foam is significantly improved by forming abundant highly stable Mn(III) active sites, which accelerate the mass transfer ability. As expected, the NiCo2O4-MnO2@Ni foam shows good bifunctional activity with a low overpotential of 0.69 V. The zinc-air battery assembled by NiCo2O4-MnO2@Ni foam exhibits a high peak power density of 576 mW cm-2, surpassing that of the Pt/C-Ir/C electrode. Additionally, benefiting from its stable flower-shaped hierarchical structure, the self-assembled electrode demonstrates long-term charge-discharge cycling stability, which lasts over 800 hours. This work provides innovative insights into enhancing MnO2-based electrodes by oxygen vacancy introduction.References N. Xu, Q. Nie, L. Luo, C. Z. Yao, Q. Gong, Y. Liu, X. Zhou, and J. Qiao, ACS applied materials & interfaces (2018).Z. Yin, R. He, H. Xue, J.-M. Chen, Y. Wang, X. Ye, N. Xu, J. Qiao and H. Huang, Energy Materials (2022).

Effect of liquid surface depression size on discharge characteristics and chemical distribution in the plasma-liquid anode system

Atmospheric pressure plasma-liquid interactions exist in a variety of applications, including wastewater treatment, wound sterilization, and disinfection. In practice, the phenomenon of liquid surface depression will inevitably appear. The applied gas will cause a depression on the liquid surface, which will undoubtedly affect the plasma generation and further affect the application performance. However, the effect of liquid surface deformation on the plasma is still unclear. In this work, numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species, and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma. Results show that the liquid surface deformation changes the initial spatial electric field, resulting in the rearrangement of electrons on the liquid surface. The charges deposited on the liquid surface further increase the degree of distortion of the electric field. Moreover, the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species, which determines the practical effectiveness of the relevant applications. This work explores the phenomenon of liquid surface depression, which has been neglected in previous related work, and contributes to further understanding of plasma-liquid interactions, providing better theoretical guidance for related applications and technologies.

Boosting and stabilizing the electrocatalytic reduction of carbon dioxide on Bi2O2CO3 via surface modification with p-aminobenzoic acid

In the realm of electrocatalytic CO2 reduction (ECR) reactions, the challenges of instability and self-reducibility present significant obstacles to the practical application of bismuth oxide-based catalysts. Herein, Bi2O3 pre-catalyst was synthesized and surface-modified with 4-aminobenzoic acid (PABA). Theoretical studies confirmed that PABA was effectively grafted through oxygen vacancies on the Bi2O3 surface, leading to electronic rearrangement. PABA efficiently prevented surface Bi3+ on Bi2O3 from self-reducing to Bi0 during the ECR reaction. The Bi2O3PABA pre-catalyst transformed into the active Bi2O2CO3PABA ECR catalyst via electrolyte mediation. A Faraday efficiency of 98.6 % for formate was achieved at −1.1 V vs. RHE, with a wide potential window of 800 mV. The current density reached 210 mA cm–2 in a 2×2 cm2 flow cell system. Theoretical calculations illustrate that PABA facilitates stabilizing the *OCHO intermediate, diminishing the adsorption barrier. These results may provide valuable insights for designing highly selective ECR catalysts through interface engineering.

Enhanced hydrogen evolution reactions: Regulating Pt-Ox bonds on bluecoke-based electrocatalyst through simple iron doping

The reconstruction of local electronic states in Pt-Ox is an effective strategy for balancing charge distribution and enhancing the intrinsic activity of noble metals. This study presents the use of highly porous and oxygen-rich activated bluecoke powders as a desirable carbon support, and regulates Pt-Ox bonds by incorporating the Fe as transition metal, leading to the development of an efficient bluecoke-based electrocatalyst characterized (Fe/Pt–O@MKABC) by exceptionally low Pt loading. The loading amount of Pt in Fe/Pt–O@MKABC is only 0.98 wt%, which is less than the 5% reported for commercial Pt/C catalyst, yet its hydrogen evolution performance is comparable. The developed catalyst presents exciting catalytic ability with overpotential of only 17 mV at 10 mA/cm2, a high mass activity of 8.3 A/(cm2·mgpt) at 50 mV, a large turnover frequency of 8.29 H2/s, and outstanding durability with a mere increase of 5 mV over 10000 cycles in acidic electrolyte. Detailed spectroscopic analysis and theoretical calculation results demonstrate that the abundant oxygen on activated bluecoke powders provides an opportunity for the construction of Fe-Oy and Pt-Ox. The introduction of Fe leads to electron rearrangement in Fe/Pt–O@MKABC, promoting electron transfer and reducing the adsorption free energy of H*, and the interaction between Fe-Oy and Pt-Ox enhances the hydrogen evolution reaction (HER) performance.

Oxygen concentration regulated the efficient liquefaction of vulcanized natural rubber

Oxidative liquefaction represents a promising avenue for the homogeneous and high-value utilization of waste tire rubber. Given that truck tires predominantly comprise natural rubber (NR), this study investigated the efficient liquefaction of vulcanized NR regulated by oxygen concentration. Remarkably, the liquefaction of vulcanized NR was realized with an oxygen concentration of 75 % at 200 °C within 3 min. FTIR spectroscopy showed that carbonyl, ether and sulphoxide groups were produced during the liquification of NR vulcanizates. Oxygen concentration significantly affected the oxidative efficiency of both the main chains and crosslinks, with a more pronounced effect observed on the main chains. Nevertheless, the similar molecular weights and polydispersity indices across various degraded products suggested a selective oxidative cleavage of the NR backbone. Furthermore, online ATR-FTIR was used to monitor the dynamic changes of NR's molecular structure to elucidate the oxidative degradation mechanism. The oxidative cleavage of NR main chain primarily occurred at the C-C bonds connected with allyl groups, producing oxidized products enriched with conjugated carbonyl groups. Alternatively, the main chain scission may also occur due to the electronic rearrangement effect of the C=C bond and produce saturated carbonyl groups. Oxygen concentration modulated the degradation efficiency of vulcanized NR, which provided an efficient strategy for the upcycling of NR-based waste tires.