Electron Interaction Effects Research Articles

Alkali Metal‐Induced Core‐Shell Hybrid with Mixed Ir Valence State Boosts Acidic Water Oxidation

AbstractIridium (Ir)‐based electrocatalysts have long been employed as the benchmark for the oxygen evolution reaction (OER) in acid, but further to improve their catalytic activity still facing great challenges. Herein, alkali metal K is incorporated to induce the in situ construction of a core‐shell hybrid of K‐IrOx thin skin‐wrapped metallic Ir (K‐IrOx/Ir) to boost the acidic OER. The K‐IrOx/Ir exhibits exceptional catalytic performance with a long lasting stability of 3000 h operation and a low overpotential of 199 mV to reach the 10 mA cm−2. Electrochemical and spectroscopic studies revealed that the enrichment of K in the low‐coordination IrOx shell induces a significant compressive strain, which regulates the Ir─O bond properties and further optimizes the adsorption energy of rate‐limiting intermediates, favoring of the enhanced catalytic activity. Furthermore, the surface IrOx active layer is well maintained during the OER process thanks to the mixed‐valence state and intensified electronic interaction in core‐shell hybrid that inhibit the overoxidation and dissolution of Ir, responsible for the outstanding stability. This work offers a novel strategy for developing high performance acidic OER catalysts by the design of favorable mesostructured architectures with mixed metal states to enable the intensified electronic interaction and strain effect.

Controlling Metal-Support Interactions to Engineer Highly Active and Stable Catalysts for COx Hydrogenation.

This perspective focuses on the modulation of metal-support interaction (MSI) in catalysts for COx hydrogenation, highlighting their profound impact on catalytic performance. Firstly, it outlines different strategies, including the use of highly reducible oxides and moderate reduction treatments, which induce the classical strong metal-support interaction (SMSI) effect and the electronic metal-support interaction (EMSI) effect. Morphology engineering and crystalline phase manipulation of oxides presented as effective methods to control EMSI are also discussed. The discrimination of SMSI and EMSI can be achieved using oxides with low encapsulation tendencies, such as ZrO2, which supports electronic modifications without or minimizing the overgrowth issues, optimizing the catalytic performance for methanation. Then, the synergy between Cu and ZnO in methanol synthesis, enhanced by SMSI, is emphasized inside. Optimizing support oxides to control oxygen vacancies enhances the catalytic performance of CO2 hydrogenation to methanol. Perspectives for the future research on the fundamental understanding of structure-MSI-performance relationship for catalyst design is discussed.

Electronic Confinement-Restrained Anti-Site Defects in Sodium-Rich Phosphates Toward Multi-Electron Transfer and High Energy Efficiency.

Sodium (Na) super-ionic conductor structured Na3MnTi(PO4)3 (NMTP) cathodes have garnered interest owing to their cost-effectiveness and high operating voltages. However, the voltage hysteresis phenomenon triggered by anti-site defects ( -ASD), namely, the occupation of Mn2+ in the Na2 vacancies in NMTP, leads to sluggish diffusion kinetics and low energy efficiency. This study employs an innovative electronic confinement-restrained strategy to achieve the regulation of -ASD. Partial replacement of titanium (Ti) with electron-rich vanadium (V) favors strong electronic interactions with Mn2+, restraining Mn2+ migration. The results suggest that this strategy can significantly increase the vacancy formation energy and migration energy barrier of manganese (Mn), thus inhibiting -ASD formation. As proof of this concept, an Na-rich Na3.5MnTi0.5V0.5(PO4)3 (NMTVP) material is designed, wherein the electronic interaction enhanced the redox activity and achieved more Na+ storage under high-voltage. The NMTVP cathode delivered a reversible specific capacity of up to 182.7 mAh g-1 and output an excellent specific energy of 513.8Wh kg-1, corresponding to ≈3.2 electron transfer processes, wherein the energy efficiency increased by 35.5% at 30C. Through the confinement effect of electron interactions, this strategy provides novel perspectives for the exploitation and breakthrough of high-energy-density cathode materials in Na-ion batteries.

WS2 Moiré Superlattices Supporting Au Nanoclusters and Isolated Ru to Boost Hydrogen Production.

Maximizing the catalytic activity of single-atom and nanocluster catalysts through the modulation of the interaction between these components and the corresponding supports is crucial but challenging. Herein, guided by theoretical calculations, a nanoporous bilayer WS2 Moiré superlattices (MSLs) supported Au nanoclusters (NCs) adjacent to Ru single atoms (SAs) (Ru1/Aun-2LWS2) is developed for alkaline hydrogen evolution reaction (HER) for the first time. Theoretical analysis suggests that the induced robust electronic metal-support interaction effect in Ru1/Aun-2LWS2 is prone to promote the charge redistribution among Ru SAs, Au NCs, and WS2 MSLs support, which is beneficial to reduce the energy barrier for water adsorption and thus promoting the subsequent H2 formation. As feedback, the well-designed Ru1/Aun-2LWS2 electrocatalyst exhibits outstanding HER performance with high activity (η10=19mV), low Tafel slope (35mVdec-1), and excellent long-term stability. Further, in situ, experimental studies reveal that the reconstruction of Ru SAs/NCs with S vacancies in Ru1/Aun-2LWS2 structure acts as the main catalytically active center, while high-valence Au NCs are responsible for activating and stabilizing Ru sites to prevent the dissolution and deactivation of active sites. This work offers guidelines for the rational design of high-performance atomic-scale electrocatalysts.

Constructing ultralow-loading Cu single atoms/Fe2O3 particles on Nb2C MXenes for efficient utilization of atomic H to boost electrochemical debromination

Bromate is a commonly identified carcinogenic and genotoxic disinfection byproduct in water. Electrochemical debromination is an environmentally friendly and effective approach but it often suffers the limited reducing atomic H (H*) ability and high metal catalyst dosage. In this study, a unique composite catalyst comprised of ultra-low loading Cu single atoms (0.016 wt%) and Fe2O3 nanoparticles supported on a Nb2C MXene (denoted as Cu0.2/Fe0.1/Nb2C) was synthesized by one-step high-temperature molten salt method. The Cu0.2/Fe0.1/Nb2C significantly outperformed the Nb2C, Cu0.2/Nb2C and Fe0.1/Nb2C counterparts in the electrochemical debromination with a 94.2 % removal efficiency of bromate. It is revealed that the introducing of Cu single atoms, efficiently promotes the adsorption of H* and inhibition of competitive H2 evolution. The incorporation of Fe2O3 nanoparticles significantly increased the electronic metal-support interaction effect between the metal components and Nb2C, thereby forming a noticeable electronic cloud bridge to facilitate efficient charge transfer. Ultimately, the synergistic interplay between Cu single atoms and Fe2O3 nanoparticles plays a crucial role in achieving the remarkable removal performance of bromate. This work not only presents a significant instance of a synergistic catalyst involving metal single atoms and metal nanoparticles for effective electrochemical debromination but also advances the understanding of the electronic metal-support interaction.

Transforming Plain LaMnO3 Perovskite into a Powerful Ozonation Catalyst: Elucidating the Mechanisms of Simultaneous A and B Sites Modulation for Enhanced Toluene Degradation.

Herein, we propose preferential dissolution paired with Cu-doping as an effective method for synergistically modulating the A- and B-sites of LaMnO3 perovskite. Through Cu-doping into the B-sites of LaMnO3, specifically modifying the B-sites, the double perovskite La2CuMnO6 was created. Subsequently, partial La from the A-sites of La2CuMnO6 was etched using HNO3, forming novel La2CuMnO6/MnO2 (LCMO/MnO2) catalysts. The optimized catalyst, featuring an ideal Mn:Cu ratio of 4.5:1 (LCMO/MnO2-4.5), exhibited exceptional catalytic ozonation performance. It achieved approximately 90% toluene degradation with 56% selectivity toward CO2, even under ambient temperature (35 °C) and a relatively humid environment (45%). Modulation of A-sites induced the elongation of Mn-O bonds and decrease in the coordination number of Mn-O (from 6 to 4.3) in LCMO/MnO2-4.5, resulting in the creation of abundant multivalent Mn and oxygen vacancies. Doping Cu into B-sites led to the preferential chemisorption of toluene on multivalent Cu (Cu(I)/Cu(II)), consistent with theoretical predictions. Effective electronic supplementary interactions enabled the cycling of multiple oxidation states of Mn for ozone decomposition, facilitating the production of reactive oxygen species and the regeneration of oxygen vacancies. This study establishes high-performance perovskites for the synergistic regulation of O3 and toluene, contributing to cleaner and safer industrial activities.

Interface engineering of MoS2–CoS2 heteronanosheets for enhanced electrochemical hydrogen evolution reaction

The heterostructured electrocatalysts with tunable electronic interaction and distinct synergetic effects have been confirmed as an efficient strategy for realizing high-performance hydrogen evolution reaction (HER). Herein, a simple synthetic strategy is reported for the growth of MoS2–CoS2 nanosheets on highly conductive reduced graphene oxide (MoS2–CoS2/RGO) to innovatively construct an electron-reconfiguration heterointerface. The strong electronic interactions between MoS2 and CoS2 interfaces lead to the redistribution of charge, which optimizes the adsorption-desorption of intermediates. Thus, the MoS2–CoS2/RGO exhibits superior catalytic activity toward HER with small overpotentials of 67 mV (1.0 M KOH) and 95 mV (0.5 M H2SO4), and remarkable stability. In addition, theoretical calculations reveal the redistribution of charge at the heterointerfaces, which decreases the energy barrier of adsorption for H intermediates and simultaneously enhances the kinetic of water dissociation. This work provides a simple strategy for designing heterostructured bimetallic electrocatalysts with a highly active interface.

Modulation effect of support on active metals in the Fe-Ni based catalysts: Insight into the electronic metal-support interaction (EMSI) effect in the CO-SCR reaction

Supported catalysts have been extensively investigated and implemented in the industry due to their cost-effectiveness and promising catalytic performance. However, due to the general inert nature of the support itself, its role in the catalyst performance is often neglected and therefore not well understood despite the consideration of the physical properties of the support. This study applies the concept of electronic metal-support interaction (EMSI) to explore the impact of various supports on the active metals in Fe-Ni-based catalysts for the CO-selective catalytic reduction reaction. Through density functional theory calculations and several advanced characterizations, it can be confirmed that the EMSI effect can modify the valence states of active metals and foster interaction between different active metals, thereby influencing the reactant adsorption and catalyst performance greatly. These findings highlight the significant impact of the support on the chemical states of active metals, having far-reaching implications for designing and optimizing the supported industrial catalysts.

Electron-interactive 1D porous vertical NiCo2O4 nanowire and 3D N-doped graphene aerogel enable high hydroxyl-ion adsorption capacity for superior energy storage

Supercapacitors are a kind of highly efficient energy-storage device with long cycle life and high power density, however, their specific capacitance is insufficient for further application and development. In this work, a novel composite with one-dimensional (1D) NiCo2O4 nanowire arrays (NiCo2O4-NWA) vertically supported on three-dimensional (3D) nitrogen-doped graphene aerogel (NGA) is designed and facilely realized by hydrothermal reaction and thermal treatment. The NiCo2O4 nanowires, with length of ∼1 μm and diameter of ∼25 nm, display a porous structure and are regularly arranged on both sides of the sheets in nitrogen-doped graphene aerogel. The aerogel-supporting NiCo2O4 nanowires demonstrate a remarkably high specific capacitance of 2742 F g−1 at 1 A g−1, and an outstanding cyclic stability with capacitance retention of 90% even after 10,000 cycles at 80 A g−1. The density functional theory calculation shows the narrow band gap (0.32 eV) and strong electronic interaction and hydroxyl-ion adsorption effect of NiCo2O4 supported on NGA, resulting in superior specific capacitance and energy storage performance. The 3D nitrogen-doped graphene aerogel supporting 1D nanowire arrays represent a promising high-performance electrode material for application in the supercapacitors and other electrochemical energy-conversion and storage equipment.

The local electronic interaction and strain effects on transverse dynamical spin susceptibility of [formula omitted]-graphyne

We present the behaviors of dynamical transverse spin susceptibilities of undoped β-graphyne monolayer using the Green’s function approach in the context of Hubbard model Hamiltonian. Such dynamical spin susceptibility is proportional to inelastic cross section of neutron beam from the layer. Specially, the effects of magnetic field, on-site coulomb repulsion strength and strain parameter on the spin excitation modes of β-graphyne monolayer are investigated via calculating correlation function of transverse components of spin density operators. Our results show the increase of absolute value of compressive strain parameter leads to move the magnetic excitation modes to higher energies. Also the intensity of peaks in inelastic cross section reduces with absolute value of compressive strain parameter. We also show that applying biaxial tensile strain causes to decrease the intensity of peaks in dynamical transverse spin susceptibility. Finally the effects of magnetic field and on-site coulomb repulsion interaction strength on frequency dependence of dynamical spin structure factor of β-graphyne layer are studied. Moreover the frequency positions of spin excitation mode of β-graphyne monolayer have been investigated due to the effects of biaxial strains, applied magnetic field and Hubbard parameter strength in details.

Regulating electronic metal-support interaction (EMSI) via pore-confinement to enhance non-thermal plasma catalytic oxidation of toluene

The non-thermal plasma catalysis holds great promise for VOCs removal, and the development of catalysts with electronic metal-support interaction (EMSI) effect is beneficial for VOCs removal. In this study, we prepared three Mn@M catalysts with EMSI coordination structures by encapsulating MnOx particles within the mesoporous molecular sieve (MCM-41) with different pore size (2.9 nm, 4.4 nm, and 7.9 nm), and investigated the effect of pore size on EMSI and non-thermal plasma catalytic performance of Mn@M for toluene. Among three catalysts, Mn@M2 with an average pore size of 4.38 nm exhibited the strongest EMSI and superior redox capabilities, thus demonstrating the highest mineralization rate, carbon balance, and CO2 selectivity for plasma catalytic oxidation of toluene. The EMSI effect leads to the formation of electron-rich and electron-poor centers on the Si-O-Mn-O bond, facilitating the generation of reactive oxygen species and enhancing the oxygen cycle. In addition, the reaction degradation pathway was investigated using in situ DRIFTS and GC–MS. This study provides valuable insights for designing highly effective supported catalysts by pore confinement to degrade VOCs in adsorption-plasma catalysis system.

Novel Mn–Bi–S hybrid mesoporous nanosheets as an efficient electrocatalyst for nitrogen reduction reaction

A non-precious and efficient catalyst was developed to enhance N2 adsorption by electronic interaction and ideal synergistic effect to improve the NRR activity.

Cyclically conjugated porphyrin trimers linked through benzo[4,5]imidazo[2,1-a]isoindole bridges.

Cyclically conjugated porphyrin trimers were prepared via a concise synthetic method. Zn-Trimer-1 displayed strong exciton coupling, suggesting the presence of effective electronic interactions. UV-Vis absorption and fluorescence spectra obtained through titration studies on the donor-acceptor adduct (Zn-Trimer-1-C60Im) indicate the occurrence of excited state photo-events.

Improving the electrocatalytic performances of Pt-based catalysts for oxygen reduction reaction via strong interactions with single-CoN4-rich carbon support

Developing platinum-group-metal (PGM) catalysts possessing strong metal-support interaction and controllable PGM size is urgent for the sluggish oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells. Herein, we propose an in-situ self-assembled reduction strategy to successfully induce highly-dispersed sub-3 nm platinum nanoparticles (Pt NPs) to attach on resin-derived atomic Co coordinated by N-doped carbon substrate (Pt/CoSA-N-C) for ORR. To be specific, the interfacial electron interaction effect, along with a highly robust CoSA-N-C support endow the as-fabricated Pt/CoSA-N-C catalyst with significantly enhanced catalytic properties, i.e., a mass activity (MA) of 0.719 A/mgPt at 0.9 ViR‑free and a reduction of 24.2% in MA after a 20,000-cycles test. Density functional theory (DFT) calculations demonstrate that the enhanced electron interaction between Pt and CoSA-N-C support decreases the d-band center of Pt, which is in favor of lowering the desorption energy of *OH on Pt/CoSA-N-C surface and accelerating the formation of H2O, thus enhance the instinct activity of ORR. Furthermore, the higher binding energy between Pt and CoSA-N-C compared to Pt and C indicates that the migration of Pt has been suppressed, which theoretically explains the improved durability of Pt/CoSA-N-C. Our work offers an enlightenment on constructing composite Pt-based catalysts with multiple active sites.

Ni2P/Co2P as a highly efficient catalyst for enhancing the electrochemical performance of P-NiMoO4 for oxygen evolution reaction

A growing trend in electrocatalysis is to explore interfacial interactions and surface intermediate adsorption in highly efficient bimetallic phosphide catalysts for developing efficient oxygen evolution reactions (OER). In this work, Ni2P and Co2P nanoparticles (NPs) were distributed on P-modified NiMoO4 nanorods prepared by the hydrothermal procedure, which exhibited high catalytic activity and outstanding durability for the OER. By regulating the high interfacial contact between Ni2P, Co2P, and P-NiMoO4, the Ni2P and Co2P NPs reduced the electron density, thus optimizing the OER. Compared to the NiMoO4 NRs, the P-NiMoO4@Ni2P/Co2P electrocatalyst showed remarkable activity towards the OER owing to the strong electron interaction and synergistic effect among the three components. Consequently, the P-NiMoO4@Ni2P/Co2P electrode yielded significant OER activity, with an overpotential of 260 mV, a Tafel slope of 41 mV/dec, and 92.9% Faradaic efficiency. Furthermore, the P-NiMoO4@Ni2P/Co2P electrocatalyst demonstrated excellent stability (up to 50 h) for the OER, which was higher than those of the NiMoO4-based catalysts reported in the literature. Several factors contribute to the excellent OER activity, including electron transfer between Ni2P, Co2P, and P-NiMoO4, and the abundant active sites generated from their interfacial interactions. Therefore, this study presents a novel approach for developing highly efficient ternary electrocatalysts for the long-term electrocatalytic evolution of oxygen.

Switchable production of aromatics and alkanes by Ni-ReOx/CeO2-catalyzed wood depolymerization

Complete conversion of lignocellulosic biomass into chemicals and fuels is particularly attractive in biorefinery concept while remains a great challenge due to complicated structure of lignocellulose and its notorious resistance to chemical transformation. Herein, a recyclable multifunctional Ni-ReOx/CeO2 catalyst was designed for switchable conversion of lignocellulose to either aromatics or liquid fuels by simple tuning reaction parameters. Under the condition of 200 °C, 1 MPa H2, lignin in woody biomass was deconstructed via lignin-first manner to produce aromatic oil with the mass yield up to 88.4 %, leaving cellulose and hemicellulose intact. Under harsher condition (260 °C, 4 MPa H2), complete conversion of lignocellulose to alkanes was achieved in 43.8 % carbon yield. The control experiments and characterization of the catalyst revealed that ReOx species of Ni-ReOx/CeO2 enhanced Ni dispersion, the strong electronic interaction and synergic effects of Ni and ReOx species played major roles for the flexible transformation.

Silver-induced adsorption optimization of adjacent Co tetrahedral sites for enhanced oxygen reduction/evolution reaction

Physical structure change of catalysts based on the electronic metal-support interaction (EMSI) effects is a prospective strategy to regulate the surface electronic structure of catalysts and further enhance their catalytic performance. To optimize the constrained intrinsic oxygen evolution reaction/oxygen reduction reaction (OER/ORR) activity of spinel MnCo2O4, we present a facile hydrothermal and photoreduction strategy to synthesize the Ag and MnCo2O4 supported on N-doped carbon nanotubes (Ag-MnCoO/NCNTs) with the EMSI effect. Ag-MnCoO/NCNTs as catalyst shows enhanced performance for OER (overpotential of 340 mV) and ORR (half-wave potential of 0.80 V). Furthermore, a zinc-air battery is assembled based on Ag-MnCoO/NCNTs cathode, which affords an open circuit potential of 1.49 V and favorable cycling performance for 200 h. Theoretical calculations illustrate the introduction of Ag reduces the charge density of the tetrahedral Co site along the direction of the dangling bonds and optimizes the adsorption of oxygen intermediates on tetrahedral Co, thus lowering the reaction activation energy and improving its oxygen catalytic activity. This work provides new insights to guide the fabrication of advanced oxygen electrocatalysts.

Effect of Electronic Interactions on Oxide-Ion Mobility in Solid Electrolytes with a Fluorite Structure

Effect of Electronic Interactions on Oxide-Ion Mobility in Solid Electrolytes with a Fluorite Structure

Systematic Characterization of Electronic Metal-Support Interactions in Ceria-Supported Pt Particles.

Electronic metal-support interactions affect the chemical and catalytic properties of metal particles supported on reducible metal oxides, but their characterization is challenging due to the complexity of the electronic structure of these systems. These interactions often involve different states with varying numbers and positions of strongly correlated d or f electrons and the corresponding polarons. In this work, we present an approach to characterize electronic metal-support interactions by means of computationally efficient density functional calculations within the projector augmented wave method. We describe Ce3+ cations with potentials that include a Ce4f electron in the frozen core, overcoming prevalent convergence and 4f electron localization issues. We systematically explore the stability and chemical properties of different electronic states for a Pt8/CeO2(111) model system, revealing the predominant effect of electronic metal-support interactions on Pt atoms located directly at the metal-oxide interface. Adsorption energies and the reactivity of these interface Pt atoms vary significantly upon donation of electrons to the oxide support, pointing to a strategy to selectively activate interfacial sites of metal particles supported on reducible metal oxides.

Effects of strong electronic interactions on the thermopower properties of the repulsive Hubbard model

Effects of strong electronic interactions on the thermopower properties of the repulsive Hubbard model