D-band Center Research Articles

Inducing Bifunctionality by Mechanical Blending of OER- and ORR-Active 3D Perovskite Electrocatalysts for Zinc-Air Batteries.

Bifunctional electrocatalysts for oxygen electrocatalysis are typically developed by combining separate OER and ORR electrocatalysts to form composites, often requiring complex synthesis methods. In this study, we present a simplified approach by mechanical blending of BaSr2CoTiSbO9 (BSCTS), an OER catalyst, with BaSr2MnTiSbO9 (BSMTS), an ORR catalyst, to construct a composite bifunctional electrocatalyst. The DFT calculation supports superior ORR activity of BSMTS due to an uplifted Mn d-band center than the Co d-band and its proximity to the Fermi level, whereas the greater OER activity of BSCTS is due to the uplifted O 2p band center. While microstructural similarity of BSCTS and BSMTS facilitates efficient mixing for composite formation, the mechanical blending avoids intervention of complex synthesis procedures. The resulting bifunctional composite electrocatalyst demonstrates excellent performance with a bifunctional index of 0.72 V and a peak power density of 125 mW/cm2 when used as an air cathode electrocatalyst in Zn-air battery (ZAB). This approach underscores the importance of mechanical blending of microstructurally compatible OER and ORR catalysts in designing practical bifunctional electrocatalysts for zinc-air batteries.

Engineered Nanozymes with Asymmetric Mn─O─Ce Sites for Intratumorally Leveraged Multimode Therapy.

Due to the enhanced flexibility of catalytic sites and synergistic effects between dual-atom active centers, dual-atom nanozymes stand out in the tumor catalytic therapy. However, precisely regulating the d-band centers of diatomic sites to break the linear-scaling relationship between intermediates remains a challenge. Herein, the hydrothermally mass-produced oxygen vacancies-engineered bimetallic silicate bio-nanoplatform with highly asymmetric O-bridged cerium─manganese (Ce─Mn) diatomic catalytic centers (CeMn-V DAs/EGCG@HA) is meticulously constructed by loading epigallocatechin-3-gallate (EGCG) and modifying with hyaluronic acid (HA) for multimodal synergistic cancer therapy. Theoretical calculations reveal that the introduction of Ce sites serves as secondary catalytic centers and upshifts d-band center of the Mn sites, thereby optimizing the adsorption/desorption of oxygen intermediates. The asymmetric Mn─O─Ce moiety facilitates electron transport within CeMn-V DAs, significantly enhancing peroxidase-like activities (Km = 27.7mM and Vmax = 3.21×10─7M s─1). Upon 650nm laser irradiation, CeMn-V DAs/EGCG inhibits heat shock protein expression, enabling mild-photothermal (η = 36.1%) therapy, which can productively inhibit tumor growth in vivo, with an inhibition rate of up to 96.2%. Due to the ligand-field effect of EGCG-Mn/Ce complexes, high-valent metal ions are effectively reduced, sustaining an intrinsic self-driven cocatalytic cycle reaction. Overall, the construction of highly asymmetric bridged diatomic nanozymes will further promote the deep integration of nanotechnology and biology.

Dual Active Site Engineering in Porous NiW Bimetallic Alloys for Enhanced Alkaline Hydrogen Evolution Reaction.

Utilizing dual active sites in electrocatalysts creates a synergistic effect, enabling the independent optimization of H2O dissociation and intermediate adsorption/desorption, which in turn enhances the efficiency of the hydrogen evolution reaction (HER). Herein, a porous NiW bimetallic alloy electrocatalyst using a dynamic H2 bubble template (DHBT) strategy is fabricated. This electrocatalyst capitalizes on the synergistic effect of dual active sites, achieving industrial-level current densities of 500 and 1000mAcm-2 for HER in 1.0M KOH, with low overpotentials of 198 and 264mV, respectively. It also demonstrates excellent stability over a 200h test. Theoretical studies reveal that alloying Ni with W shifts the d-band center (εd) of the W 5d orbital downward, which enhances *OH intermediate desorption and promotes H2O adsorption and dissociation at the W site, leading to increased active site availability. Meanwhile, this shift provides more accessible H* intermediates, further enhancing H2 production at the Ni2W1 hollow site. When the porous NiW bimetallic alloy electrocatalyst is implemented in a solar-driven water splitting system, it achieves a high solar-to-hydrogen (STH) conversion efficiency of 16.59%. This work underscores the effectiveness of dual active site electrocatalysts for sustainable H2 production.

An Enhanced "Trapping-Conversion" Function Enables Ultrastable Potassium Ion Storage.

Metal chalcogenides (MCs) have emerged as promising candidates for potassium ion battery (KIB) anode materials, yet the sluggish redox kinetics and notorious shuttle effect inescapability lead to inferior rate performance and poor cyclability. Herein, a P-doped PbTe/MXene (P-PbTe/MXene) superstructure is rationally constructed by decorating PbTe on MXene via a hydrothermal reaction and followed by bifunctional P-doping, where P heteroatoms enter both PbTe and MXene lattice. The P-PbTe/MXene anode shows enhanced reaction kinetics and suppressed shuttle effect of polytellurides due to the enhanced chemical adsorption stemming from the low energy gaps between the d-band center and the p-band center of P-MXene. As a result, the P-PbTe/MXene superstructure shows superior potassium storage properties, including high reversible capacity (289.1 mAh g-1 at 0.2 A g-1 after 200 cycles), outstanding rate performance (151.3 mAh g-1 at 20 A g-1), and ultrastable cyclability (180.1mA h g-1 at 2.0 A g-1 after 2000 cycles) in half battery. Also, the P-PbTe/MXene anode exhibits high energy density (186.0Wh kg-1 at 0.1 A g-1) and excellent bending stability in soft-package full cells.

Charge Self-Regulation at the Interface Engineering of the Metallic Heterostructure NiCoP@Co3S4 for Efficient Alkaline Overall Water Splitting.

Developing heterostructures with high electrical conductivity and appropriate adsorption strength for oxygen intermediates is a crucial strategy to reduce the energy consumption of overall water splitting (OWS) and enhance the economic viability of hydrogen energy. This article proposes a novel metallic heterostructure (NiCoP@Co3S4) that is in situ grown on nickel foam. The composite of NiCoP and Co3S4 not only promotes effective charge transfer in the heterojunction and accelerates the kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) but also optimizes the electronic structure of the catalyst through interface engineering. Density functional theory (DFT) calculations demonstrate that the formation of the heterostructure significantly increases the density of electronic states near the Fermi level (EF), thereby enhancing conductivity. Moreover, the d-band center of NiCoP@Co3S4 shifts closer to EF, which enhances the binding strength of reaction intermediates to the catalyst's active sites. This shift lowers the reaction activation energy and thus promotes the catalytic process. Experimental results show that the NiCoP@Co3S4 heterostructure exhibits excellent performance in both HER (η10 = 62 mV) and OER (η10 = 203 mV). An electrolyzer composed of NiCoP@Co3S4 electrodes requires only a potential of 1.48 V to achieve a current density of 10 mA cm-2. Additionally, it demonstrates good stability over 100 h of testing, outperforming the Pt/C || RuO2 catalyst (1.51 V@10 mA cm-2). This work provides an effective approach to achieving efficient water splitting for hydrogen production at low overpotentials through the self-regulation of charge in heterostructures, offering new insights for the design of efficient non-noble metal-based electrocatalysts.

Enhanced Electrocatalytic Carbon Dioxide Reduction Activity via Local Charge Environment Regulation of Active Sites with Rational Functionalization.

Covalent organic frameworks (COFs) are a new emerging class of electrochemical catalysts for the CO2 reduction reaction (CO2RR) with fascinating structural tunability. In this work, to dig more detailed information about the effect of local charge environment regulation of active sites via structure modification on the catalytic performance of COFs for CO2RR, the Gibbs free-energy change (ΔG) of each elementary reaction step involved in the CO2RR and competitive hydrogen evolution reaction (HER) on COF366-Co and its derivatives were examined theoretically. It is observed that the valence band maximum (VBM) energy level of the COFs is increased by incorporation of electron-donating groups, and then the charge distribution on the Co center of COF366-Co is increased due to the increased charge-transfer amount from the electron-occupied N sp2 hybrid orbitals to the empty Co3d orbitals. For incorporating electron-withdrawing groups, the VBM energy level and the d-band center (ξd) of the Co atom are downshifted, and the d-band center gets closer to the occupied VBM energy level as the VBM is decreased to a larger extent than the ξd. As a result, electrosorption of the intermediate is facilitated and the CO2RR performance is enhanced by such a linker functionalization strategy, especially for electron-withdrawing groups. Our study highlights the key role that controlled local electrical environment via chemical structure modification of COFs can play in regulating the catalytic activity for its CO2RR applications.

Atomically Dispersed Sn on Core-Shell MoS2 Nanoreactors as Mott-Schottky Phase Junctions for Efficient Electrocatalytic Hydrogen Evolution.

The electrocatalytic hydrogen evolution reaction (HER) plays a pivotal role in electrochemical energy conversion and storage. However, traditional HER catalysts still face significant challenges, including limited activity, poor acid resistance, and high costs. To address these issues, a hollow core-shell structured 2H@1T-MoS2-Sn1 nanoreactor is designed for acidic HER, where Sn single atoms are anchored on the shell of 2H@1T-MoS2 Mott-Schottky phase junction. The 2H@1T-MoS2-Sn1 catalyst demonstrates exceptional HER performance, achieving an ultralow overpotential of 9mV at 10mA cm-2 and a Tafel slope of 16.3mV dec-1 in acidic media-the best performance reported to date among MoS2-based electrocatalysts. The enhanced performance is attributed to the internal electric field at the Mott-Schottky phase junction, which facilitates efficient electron transfer. Additionally, the Sn single atoms modulate the electronic structure of Mo atoms within the Sn-S2-Mo motif, inducing a significant shift in the d-band center and thereby optimizing the dehydrogenation process. This work presents a novel electrocatalyst design strategy that simultaneously engineers interfacial charge transfer and surface catalysis, offering a promising approach for advancing energy conversion technologies.

Rational Design of Highly Stable and Active Single-Atom Modified S-MXene as Cathode Catalysts for Li-S Batteries.

The practical application of Li-S batteries is hindered by the shuttle effect and sluggish sulfur conversion kinetics. To address these challenges, this work proposes an efficient strategy by introducing single atoms (SAs) into sulfur-functionalized MXenes (S-MXenes) catalysts and evaluate their potential in Li-S batteries through first-principles calculations. Using high-throughput screening of various SA-modified S-MXenes, this work identifies 73 promising candidates that exhibit exceptional thermodynamic and kinetic stability, along with the effective immobilization of polysulfides. Notably, the incorporation of Ni, Cu, or Zn as SAs into S-MXenes results in a significant Gibbs free energy barrier reduction by 51%-75%, outperforming graphene-based catalysts. This reduction arises from SA-induced surface electron density that influences the adsorption energies of intermediates and thereby disrupts the scaling relations between Li₂S₂ and other key intermediates. Further enhancement in catalytic performance is achieved through strain engineering by shifting the d-band center of metal atoms to higher energy levels, increasing the chemical affinity for intermediates. To elucidate the intrinsic adsorption properties of intermediates, this work develops a machine learning model with high accuracy (R2 = 0.88), which underscores the pivotal roles of SA electronegativity and local coordination environment in determining adsorption strength, offering valuable insights for the rational design of catalysts.

Site-Specific Spin State Modulation in Spinel Oxides for Enhanced Nonradical Oxidation.

Spinel oxides hold tremendous potential for driving advanced oxidation processes, yet the underlying mechanism for maximizing their activity remains unclear. In this study, we leverage tetrahedral and octahedral site interactions in MnxCo3-xO4 to modulate the spin states, specifically spin alignment and spin moment, thereby enhancing periodate (PI) activation and catalytic performance in contaminant degradation. Through combined experimental and density functional theory (DFT) analyses, we elucidate the role of spin alignment at synergetic tetrahedral and octahedral sites in facilitating a quantum spin exchange interactions (QSEI) with an efficient electronic spin channel for charge transfer. Meanwhile, the engineered high spin configuration in CoMn2O4 raises the d-band center, favoring stable PI* surface complex formation and accelerating the rate-determining desorption of IO3- with a lower -ICOHP value during the catalytic degradation of ciprofloxacin. As a result, the fine-tuned spin state of CoMn2O4 leads to enhanced overall reaction kinetics, with a 2.5-fold increase compared to MnCo2O4and up to 22-fold increase compared to the octahedrally-active only catalysts. Such a site-specific modulation has been found applicable to other spinel oxides, enlightening fine-tuned electronic structure for maximizing catalytic performance.

Amorphous/Crystalline Heterostructured Nanoporous High-Entropy Metallic Glasses for Efficient Water Splitting

Abstract Developing nanoporous high-entropy metallic glass (HEMG) with a high specific surface area presents a promising approach to develop a cost-effective and efficient catalyst, which utilizes the synergistic effect of its multi-component composition and the adjustable atomic environment of its disordered structure. However, the glass structure invariably gets erased due to the inevitable crystallization during the nanoporous construction procedure through dealloying. Here, an innovative HEMG with an endogenetic nano-scale phase-separated structure is specially designed to maintain a fully glassy state throughout the nanoporous construction procedure. Consequently, an amorphous/crystalline heterostructure (ACH)—nanocrystal flakes embedded in amorphous ligaments—is intentionally constructed, which exhibits significant lattice distortion at amorphous/crystalline interfaces, resulting in high density of active sites. The ACH facilitates intermediate adsorption by promoting directional charge transfer between amorphous and crystalline phases and improves product desorption through downshifting the d-band center. This results in remarkable electrolysis performance, requiring only a 1.53 V potential to achieve a current density of 10 mA cm-2 for overall water-splitting in an alkaline electrolyte, surpassing that of commercial Pt/C || IrO2 catalysts of 1.62 V. This research pioneers strategies to refine the composition, atomic structure, and electron characteristics of HEMG, unlocking new functional applications.

D-band state control engineering over ZnIn2S4 for enhanced photoreduction of CO2 to CH4.

D-band state control engineering over ZnIn2S4 for enhanced photoreduction of CO2 to CH4.

Ce-doping-induced defect effects boosting H2 generation

Ce-doping-induced defect effects boosting H2 generation

Radical to non-radical conversion during PMS activation triggered by optimized electronic structure: Orientational regulation of oxidation pathway for water remediation

Radical to non-radical conversion during PMS activation triggered by optimized electronic structure: Orientational regulation of oxidation pathway for water remediation

The application and research progress of d-band center theory in the field of water electrolysis

The application and research progress of d-band center theory in the field of water electrolysis

D-band center modulation of atomic dispersed FeNx sites by incorporating Co9S8 nanoparticles towards augmented ORR/OER electrocatalysis in Zn-air batteries

D-band center modulation of atomic dispersed FeNx sites by incorporating Co9S8 nanoparticles towards augmented ORR/OER electrocatalysis in Zn-air batteries

Promoting effect of d-band center and in-situ precipitation strategy on sulfur evolution reaction

Promoting effect of d-band center and in-situ precipitation strategy on sulfur evolution reaction

Descriptor for electro-oxidation of glycerol with high-efficiency bifunctional Cu-Nx single atom catalyst and coupled with hydrogen evolution/carbon dioxide reduction.

Descriptor for electro-oxidation of glycerol with high-efficiency bifunctional Cu-Nx single atom catalyst and coupled with hydrogen evolution/carbon dioxide reduction.

The activity origin of two-dimensional MN4-contained periodical macrocyclic structures towards electro-catalytic hydrogen evolution.

The activity origin of two-dimensional MN4-contained periodical macrocyclic structures towards electro-catalytic hydrogen evolution.

Rapid carrier extraction and d-band center regulation of Pd-ZnIn2S4 for efficient photocatalytic water splitting

Rapid carrier extraction and d-band center regulation of Pd-ZnIn2S4 for efficient photocatalytic water splitting

Engineering active sites on N, S co-doped carbon matrix-encapsulated Ni-modified Co9S8 nanoparticles enabling efficient urea electrooxidation.

Engineering active sites on N, S co-doped carbon matrix-encapsulated Ni-modified Co9S8 nanoparticles enabling efficient urea electrooxidation.