D-band Center Research Articles

What Is the Mechanism by which the Introduction of Amorphous SeOx Effectively Promotes Urea-Assisted Water Electrolysis Performance of Ni(OH)2?

Nickel hydroxide (Ni(OH)2) is considered to be one of the most promising electrocatalysts for urea oxidation reaction (UOR) under alkaline conditions due to its flexible structure, wide composition and abundant 3D electrons. However, its slow electrochemical reaction rate, high affinity for the reaction intermediate *COOH, easy exposure to low exponential crystal faces and limited metal active sites that seriously hinder the further improvement of UOR activities. Herein it is reported electrocatalyst composed of rich oxygen-vacancy (Ov) defects with amorphous SeOx-covered Ni(OH)2 (Ov-SeOx/Ni(OH)2). Surprisingly, at 100 mA cm-2, compared with Ni(OH)2 (1.46 V (vs RHE)), Ov-SeOx/Ni(OH)2 has a potential of 1.35 V. Meanwhile, Ov-SeOx/Ni(OH)2 catalyst also showed good hydrogen evolution reaction (HER) performance, so it is used as the electrolytic cell assembled by UOR and HER bifunctional catalysts and only 1.57 V could reach 100 mA cm-2. Density functional theory (DFT) study revealed that introduce of amorphous SeOx optimizes the electronic structure of the central active metal, amorphous/crystalline interfaces promote charge-carrier transfer, shift d-band center and entail numerous spin-polarized electrons during the reaction, which speeds up the UOR reaction kinetics.

Workflow-driven catalytic modulation from single-atom catalysts to Au–alloy clusters on graphene

Gold-based (Au) nanostructures are efficient catalysts for CO oxidation, hydrogen evolution (HER), and oxygen evolution (OER) reactions, but stabilizing them on graphene (Gr) is challenging due to weak affinity from delocalized carbon orbitals. This study investigates forming metal alloys to enhance stability and catalytic performance of Au-based nanocatalysts. Using ab initio density functional theory, we characterize sub-nanoclusters (M = Ni, Pd, Pt, Cu, and Ag) with atomicities , both in gas-phase and supported on Gr. We find that M atoms act as “anchors,” enhancing binding to Gr and modulating catalytic efficiency. Notably, /Gr shows improved stability, with segregation tendencies mitigated upon adsorption on Gr. The d-band center () model indicates catalytic potential, correlating an optimal range of eV for HER and OER catalysts. Incorporating Au into adjusts closer to the Fermi level, especially for Group-10 alloys, offering designs with improved stability and efficiency comparable to pure Au nanocatalysts. Our methodology leveraged SimStack, a workflow framework enabling modeling and analysis, enhancing reproducibility, and accelerating discovery. This work demonstrates SimStack’s pivotal role in advancing the understanding of composition-dependent stability and catalytic properties of Au-alloy clusters, providing a systematic approach to optimize metal-support interactions in catalytic applications.

Synergistic Atomic Environment Optimization of Nickel-Iron Dual Sites by Co Doping and Cr Vacancy for Electrocatalytic Oxygen Evolution.

The dual-site synergistic catalytic mechanism on NiFeOOH suggests weak adsorption of Ni sites and strong adsorption of Fe sites limited its activity toward alkaline oxygen evolution reaction (OER). Large-scale density functional theory (DFT) calculations confirm that Co doping can increase Ni adsorption, while the metal vacancy can reduce Fe adsorption. The combined two factors can further modulate the atomic environment and optimize the free energy toward oxygen-containing intermediates, thus enhancing the OER activity. Accordingly, we used Co doping and Cr vacancies to fabricate an amorphous catalyst of VCr,Co-NiFeOOH. It provides an OER overpotential of 239 mV at 100 mA cm-2 and high stability over 500 h at 500 mA cm-2 with a ∼98% potential retention. The resulting water electrolyzer based on an anion exchange membrane (AEM) exhibits a remarkable performance of 1 A cm-2 at 1.68 V in 1 M KOH. XPS, soft-XAS, and XANES combined with Bader charge analysis results reveal that the regulation of the local microenvironment can increase the valence state of Ni by Co doping, thus improving the adsorption energy on Ni sites. The Cr vacancy can alleviate the strong adsorption on Fe sites. DFT calculations confirm that the synergistic effect of Co doping and Cr vacancies can redistribute the charge on the Ni/Fe sites, optimize the d-band center of Ni and Fe, and endow the catalyst with Ni-Fe dual sites to reduce the energy barrier of the OER rate-determining step.

HCP-to-FCC Phase Transformation of Ruthenium Nanocrystals Selectively Activate Hydrogen Peroxide for Boosting Peroxidase-like Activity.

Due to the simultaneous activation of hydrogen peroxide (H2O2) and oxygen, Ru nanocrystals exhibit inherent peroxidase- and oxidase-like activities, thereby limiting their extensive application in biosensing. Phase engineering of Ru nanocrystals holds great promise for enhancing catalytic activity and selectivity but remains a challenge. Here, highly active Ru nanocrystals with a metastable face-centered cubic (fcc) structure were successfully synthesized via a facile wet-chemical method followed by an etching step, enabling selective activation of H2O2 and demonstrating promising peroxidase-like activity. Compared to the thermodynamically favored hexagonal close-packed Ru nanocrystals, the resultant fcc Ru shows an over 5-fold enhancement in the maximum reaction velocity of the peroxidase-like catalysis, while its oxidase-like performance exhibits a minor decline, indicating a transition from multienzyme activity to specificity. Theoretical calculations reveal that the phase transformation of Ru not only results in an upward shift of the d-band center to enhance H2O2 adsorption but also regulates the O-O bonding strength of H2O2 to achieve selective H2O2 activation. As a proof of concept, a colorimetric sensor based on fcc Ru nanocrystals was successfully constructed, achieving accurate and sensitive detection of organophosphorus pesticides. This work not only offers promising prospects for phase engineering of Ru nanocrystals but also highlights the significance of the Ru phase transition in hydrogen peroxide activation.

Enhanced Cooperative Generalized Compressive Strain and Electronic Structure Engineering in W-Ni3N for Efficient Hydrazine Oxidation Facilitating H2 Production.

As promising bifunctional electrocatalysts, transition metal nitrides are expected to achieve an efficient hydrazine oxidation reaction (HzOR) by fine-tuning electronic structure via strain engineering, thereby facilitating hydrogen production. However, understanding the correlation between strain-induced atomic microenvironments and reactivity remains challenging. Herein, a generalized compressive strained W-Ni3N catalyst is developed to create a surface with enriched electronic states that optimize intermediate binding and activate both water and N2H4. Multi-dimensional characterizations reveal a nearly linear correlation between the hydrogen evolution reaction (HER) activity and the d-band center of W-Ni3N under strain state. Theoretically, compressive strain enhances the electron transfer capability at the surface, increasing donation into antibonding orbitals of adsorbed species, which accelerates the HER and HzOR. Leveraging both compressive strain and the modified electronic structure from W incorporation, the W-Ni3N catalysts demonstrate outstanding bifunctional performance, achieving overpotentials of 46mV for HER at 10mA cm-2 and 81mV for HzOR at 100mA cm-2. Furthermore, W-Ni3N catalyst achieves efficient overall hydrazine splitting at a low cell voltage of 0.185V for 50mA cm-2, maintaining stability for ≈450 h. This work provides new insights into the dual engineering of strain and electronic structure in the design of advanced catalysts.

Identifying Upper d-Band Edge as Activity Descriptor for Ammonia Oxidation on PtCo Alloys in Low-Temperature Direct Ammonia Fuel Cells.

Low-temperature direct ammonia fuel cell (DAFC) stands out as a more secure technology than the hydrogen fuel cell system, while there is still a lack of elegant bottom-up synthesis procedures for efficient ammonia oxidation reaction (AOR) electrocatalysts. The widely accepted d-band center, even with consideration of the d-band width, usually fails to describe variations in AOR reactivity in many practical conditions, and a more accurate activity descriptor is necessary for a less empirical synthesis path. Herein, the upper d-band edge, εu, derived from the d-band model, is identified as an effective descriptor for accurately establishing the descriptor-activity relationship. Using the PtCo alloy with varying atomic composition as an example, the εu value succeeds in reflecting the corresponding trends of AOR activity, showing striking linear correlation with a coefficient of determination (R2) as high as 0.90. The effectiveness of the established descriptor-activity relationship is verified experimentally. The optimum electrocatalyst delivers an excellent peak current density of 74.04 A g-1 at 5 mV s-1, and the assembled DAFC generates a high power density, outperforming the majority of the extensively reported systems. This work brings fundamental insights into the relationship between chemical reactivity and electronic structure and benefits rational optimization of AOR electrocatalyst for next-generation low-temperature DAFC.

Interfacial engineering of ZnS-FeS heterostructure accelerates Li2S2 reduction and impedes the dendritic Li growth

The andante electrocatalytic conversion and grievous shuttle effect of lithium polysulfides (LiPSs) lead to stagnant applications of lithium-sulfur (Li-S) batteries. Plentiful catalysts such as ZnS-FeS heterostructures have been employed to solve those problems. However, the mechanism of this heterostructures on sulfur reduction reaction (SRR) especially the conversion of Li2S2 to Li2S (Li2S2RR) and Li+ migration has not been revealed. Herein, a ZnS-FeS heterostructures embedded in hierarchical porous carbon (ZnS-FeS/HPC) was demonstrated that can act as effective catalyst to accelerate Li2S2RR and promote the Li+ diffusion simultaneously. This improvement can be attributed to the moderate adsorption energy and lower d-band center of the heterostructures to reaction intermediates. Moreover, with both homogeneous porous structure and abundant polarity sites, the modified separator using ZnS-FeS/HPC was endowed with selectivity to promote uniform Li+ flux and migration, as well as impede the dendritic Li growth and LiPSs shuttling. Benefited from above advantages, the batteries exhibited superior initial capacity of 1674.7 mAh/g (current density: 0.2C). Even at 3C, the batteries can cycle steadily for over 1500 cycles along with ultralow rate of capacity decay (0.044 %). This work opens up a new insight to explore bidirectional catalyst for realizing remarkable performance Li-S batteries.

CO driven tunable syngas synthesis via CO2 photoreduction using a novel NiCo bimetallic metal-organic frameworks.

Syngas has important industrial applications, and converting CO2 to CO is critical for syngas production. Metal-organic frameworks (MOFs) have demonstrated significant potential in photocatalytic syngas conversion, although the impact of catalytic reactions on tunable H2/CO ratios remains unclear. Herein, we present a novel bimetallic NiCo-MOF catalyst, Ni0.4Co0.6, exhibiting high catalytic activity in syngas conversion due to the CO product self-driven effect. Our investigation, integrating experimental data with density functional theory (DFT) analysis, uncovers a high photocurrent response and a low charge-transfer resistance. Furthermore, the introduction of cobalt into Ni-MOF caused an upshift of the d-band center, which facilitated the conversion efficiency of *COOH intermediates, which has been identified as the rate-determining step in CO2 conversion, resulting in increased CO yield. Additionally, the concentration of undesorbed CO rises, while CO co-adsorption diminishes the catalyst's binding energy for *H, thereby enhancing H2 generation. These combined effects contribute to a self-driven enhancement in the catalytic production of syngas. By adjusting the Ni/Co ratio, a tunable H2/CO ratio (0.21-0.85) was achieved, with Ni0.4Co0.6 exhibiting optimal catalytic performance, yielding 17.6mmol·g-1·h-1 gas products. This study provides a novel insight into the correlation between reaction products and catalyst design, offering a perspective on perspective on modulating syngas composition.

Spin effects in regulating the adsorption characteristics of metal ions.

Understanding the adsorption behavior of intermediates at interfaces is crucial for various heterogeneous systems, but less attention has been paid to metal species. This study investigates the manipulation of Co3+ spin states in ZnCo2O4 spinel oxides and establishes their impact on metal ion adsorption. Using electrochemical sensing as a metric, we reveal a quasi-linear relationship between the adsorption affinity of metal ions and the high-spin state fraction of Co3+ sites. Increasing the high-spin state of Co3+ shifts its d-band center downward relative to the Fermi level, thereby weakening metal ion adsorption and enhancing sensing performance. These findings demonstrate a spin-state-dependent mechanism for optimizing interactions with various metal species, including Cu2+, Cd2+, and Pb2+. This work provides new insights into the physicochemical determinants of metal ion adsorption, paving the way for advanced sensing technologies and beyond.

Anchoring Ru-Ru2P heterojunction on P-doped graphene for enhanced HER performances of water electrolysis

Highly active and stable electrocatalysts are highly desired for the hydrogen evolution reaction (HER) in water electrolysis. In this study, a ruthenium-ruthenium phosphide heterojunction (Ru-Ru2P) anchored on phosphorus-doped graphene (PCSG) was fabricated via a mild molten salt template method. The graphene was synthesized from discarded coconut shells sourced from Hainan. We found that the heterojunction structure could accelerate electron transfer, while the graphene provided more exposed active sites, significantly enhancing the HER activity of the catalyst. The catalyst prepared at 800 °C with 30mg of RuCl3 (Ru-Ru2P/2D-PCSG-800) exhibited low HER overpotentials of 31mV in alkaline and 57mV in acidic electrolytes at a current density of 10mAcm-2, respectively, which were comparable to those of commercial 20% Pt/C catalyst (36mV in alkaline and 40mV in acidic electrolytes). Moreover, the catalyst demonstrated high stability with no significant change in current density after 125hours of operation. Density functional theory calculations revealed that the Ru-Ru2P heterojunction could rearrange charge and modify the Ru d-band center, optimizing the adsorption energy of active ⁎H (|ΔG⁎H|) and breakage energy of ⁎H-OH bond (ΔGH2O).

Single-atom Pd directly anchored on biphenylene: a promising bifunctional electrocatalyst for overall water splitting.

The development of bifunctional single-atom catalysts (SACs) for overall water splitting is crucial for clean energy production in the context of sustainable development. Using first-principles calculations, the catalytic capability of different transition metal (TM) atoms supported on biphenylene (Bip) monolayers (TM@Bip, TM = V-Cu, Ru-Ag, and Ir-Au) is comprehensively investigated. Bip can directly anchor TM atoms without engineered vacancies or nitrogen defects. Among the screened SACs, Pd@Bip is found to be an excellent bifunctional catalyst for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The overpotentials for the HER and the OER were calculated to be 0.05 and 0.50 V, respectively, which are even superior to the commercialized catalysts like Pt and IrO2. Furthermore, adjusting the d-band center of TM atoms effectively modulates the catalytic activity, and the optimal OER performance of TM-Bip can be achieved with a d-band center of -2.32 eV, which can serve as a principle to design Bip-based SACs. Our findings may serve as a practical theoretical guide for the exploration of effective bifunctional SACs for overall water splitting.

Efficient Bifunctional Electrocatalysts for Oxygen Evolution/Reduction Reactions in Two-Dimensional Metal-Organic Frameworks by a Constant Potential Method.

The evolution of bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts that are highly active, stable, and conductive is crucial for advancing metal-air batteries and fuel cells. We have here thoroughly explored the OER and ORR performance for a category of two-dimensional (2D) metal-organic frameworks (MOFs) called TM3(HADQ)2, and Rh3(HADQ)2 exhibits a promising bifunctional OER/ORR activity, with an overpotential of 0.31 V for both OER and ORR. The d-band center (εd) and crystal orbital Hamilton populations (COHP) are utilized to study the relationship between OER/ORR activity and the electronic structure of catalysts, and it is found that the elementary d-electron number (Ne) of the central TM for TM3(HADQ)2, as well as the electronegativity of the ligand TM-N4 and the intermediate O atom, are the main reason that affects the catalytic activity of OER/ORR. Additionally, Rh3(HADQ)2 can be proven through the constant potential method (CPM) and microkinetics method that it is an acidic OER/ORR bifunctional catalyst. Rh3(HADQ)2 has a high toxicity tolerance, making it a potential bifunctional catalyst. Our research contributes to both the rational design of SACs for various catalytic processes and the fabrication of bifunctional, cost-effective oxygen-electric catalysts.

Modulation of the Second-Beyond Coordination Structure in Single-Atom Electrocatalysts for Confirmed Promotion of Ammonia Synthesis.

Although microenvironments surrounding single-atom catalysts (SACs) have been widely demonstrated to have a remarkable effect on their catalytic performances, it remains unclear whether the local structure beyond the secondary coordination shells works as well or not. Herein, we employed a series of metal-organic frameworks (MOFs) with well-defined and tunable second-beyond coordination spheres as model SAC electrocatalysts to discuss the influence of long-distance structure on the ammonia synthesis from nitrate, which were synthesized and denoted as Cu12-NDI-X (X = NMe2, H, F). It is first experimentally confirmed that the remote substitution of function groups beyond the secondary coordination sphere can remarkably affect the activity of ammonia synthesis. Meanwhile, the -H endowed Cu12-NND-H exhibits a superior ammonia yield (35.1 mg·h-1·mgcat-1) and FE (98.7%) to those modified with -NMe2 and -F, which also shows good stability at 100 mA·cm-2. The remarkable promotion of the modulated second-beyond coordination structure is unraveled to result from the adjustable d-band center of the Cu active site leading to promoted adsorption of the NO3- and protonation of key intermediates. Encouraged by its extraordinary ammonia yield, we employed the Cu12-NND-H electrode as a cathode to assemble one rechargeable Zn-nitrate battery that exhibits an impressive power density of 34.0 mW·cm-2, demonstrating its promising application in energy conversion and storage.

Towards Rational Design of Confined Catalysis in Carbon Nanotube by Machine Learning and Grand Canonical Monte Carlo Simulations.

The microenvironment is recognized to be as crucial as active sites in heterogeneous catalysis. It was found that the catalytic activity of a set of chemical reactions can be significantly influenced by the confined space of carbon nanotubes (CNTs), with some reactions showing superior activity, while others experience a negative impact. The rational design of confined catalysis must rely on the accurate insights of confined microenvironment. However, the structural complexity of confined catalysts and the interaction with microenvironment hinders the deciphering of chemical origins behind experiments. In this work, Grand-canonical Monte Carlo (GCMC) simulations are conducted for confined catalysis in CNTs at various reaction atmospheres, accelerated by machine learning potentials. The statistical outcomes of GCMC simulations corroborate a general feature that the electronic interaction (binding energy) inside CNTs is weaker than outside cases. By using Random Forest (RF) model, we ascertain that the shortening of the bond lengths of catalysts within the confined space is the dominant factor, resulting in the weakened binding energy and the downshift of the d-band center. Using the bond length variation as a simplified descriptor, our microkinetic models successfully reproduced the seemingly contradictive experiments, namely, the observed enhancement and suppression for the same reaction.

Direct Observation of Hybridization Between Co 3d and S 2p Electronic Orbits: Moderating Sulfur Covalency to Pre-Activate Sulfur-Redox in Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) offer high energy density and environmental benefits hampered by the shuttle effect related to sluggish redox reactions of long-chain lithium polysulfides (LiPSs). However, the fashion modification of the d-band center in separators is still ineffective, wherein the mechanism understanding always relies on theoretical calculations. This study visibly probed the evolution of the Co 3d-band center during charge and discharge using advanced inverse photoemission spectroscopy/ultraviolet photoemission spectroscopy (IPES/UPS), which offers reliable evidence and are consistent well with theoretical calculations. This, coupled with in situ Raman and X-ray diffraction (XRD) and electrochemical data, co-evidences a novel pre-activating S redox mechanism in LSBs: LiPSs desert/insert in C-N matrixes within a series of Co@NCNT-based separators. The insight of the S redox pre-activation is discovered that the Co 3d-band center downshifts to hybridized with S 2p orbitals in LiPSs, giving rise to a more pronounced S covalency and thus accelerating the conversion of LiPSs to S₈. Benefiting from these advantages, the optimized LSB possesses a minimal decay rate of 0.0058% after 200 cycles at a high discharge rate of 10 C. This study provides new insights into LSB mechanisms and supports conventional theoretical models of the d-band center's impact on LSB performance.

Magnesium Oxide-Supported Single Atoms with Fine-Modulated Steric Location for Polymerization Transfer Removal of Water Pollutants.

Organic pollutants removal via a polymerization transfer (PT) pathway based on the use of single-atom catalysts (SACs) promises efficient water purification with minimal energy/chemical inputs. However, the precise engineering of such catalytic systems toward PT decontamination is still challenging, and the conventional SACs are plagued by low structural stability of carbon material support. Here, we adopted magnesium oxide (MgO) as a structurally stable alternative for loading single copper (Cu) atoms to drive peroxymonosulfate-based Fenton-like reactions. Through fine-tuning the Cu atom steric location from lattice-embedding to surface-loading, the system exhibited a fundamental transition in the catalytic pathways toward the PT process and drastically improved decontamination efficiency. The catalytic pathway change was mainly ascribed to a downshifted d-band center of the Cu atoms. The optimized catalyst achieved complete, rapid removal of phenolic compounds from water via nearly 100% PT pathway, accompanied by high oxidant utilization efficiency surpassing most state-of-the-art SACs. Moreover, it showed excellent structural stability and environmental robustness and was successfully used for the treatment of lake water and industrial coking wastewater. The adaptability of the spatial engineering strategy to other MgO-supported single atoms, including Fe, Co, and Ni SACs, was also demonstrated. Our work lays a foundation for further advancing SACs-based advanced oxidation technologies toward sustainable water purification applications.

Synergistic Enhancement of Plasma-Driven Ammonia Synthesis Using a AuCu3/Cu Composite Catalyst.

Green ammonia synthesis using fluctuating renewable energy supply in decentralized process is a goal that has been long sought after. Ammonia synthesis with non-thermal plasma under mild conditions is a promising technology, but it faces the critical challenge of low energy efficiency. Herein, we develop an easily-scalable AuCu3/Cu catalyst, which consists of a decimeter-scale metallic Cu antenna and nano-scale AuCu3 catalytic sites on metallic Cu surface, significantly enhancing the energy efficiency and ammonia yield in a radio-frequency (RF) plasma system. Compared to plasma alone, the single-pass ammonia yield over AuCu3/Cu increases by a factor of 20, approaching 10 %. Mechanistic studies indicate that Cu antenna can amplify the millimeter-scale local electric field, thereby facilitating the generation of active nitrogen species, including nitrogen radicals and vibration-excited nitrogen molecules. Due to the downshifted d-band center and unique Cu-Au interface structure, the AuCu3 nanoalloy modified on Cu antenna surface significantly reduces hydrogenation barriers of active NHX (x=0,1,2) species (the rate-determining step) and facilitates ammonia desorption at lower temperature. The synergistic effect of Cu antenna and surface AuCu3 nanoalloy comprehensively enhances ammonia synthesis through both the nitrogen radical-mediated Eley-Rideal pathway and the vibration-excited nitrogen molecule-mediated Langmuir-Hinshelwood pathway.

Unconventional Interconnected High-Entropy Alloy Nanodendrites for Remarkably Efficient C-C Bond Cleavage toward Complete Ethanol Oxidation.

Developing ethanol oxidation electrocatalysts with high catalytic activity, durability, and resistance to CO poisoning remains a major challenge. High-entropy alloys (HEAs) with unique physical and chemical properties have garnered substantial attention. Herein, a class of HEA nanodendrites are designed by a simple wet-chemical method. The mass activity and specific activity of the septenary PtIrRhCoFeNiCu high-entropy alloy catalyst are 2.13 A mgPt-1/1.05 A mgPt+Ir+Rh-1 and 2.95 mA cm-2, which reach 5.76-/2.84-fold and 5.57-fold improvements relative to commercial Pt/C (0.37 A mgPt-1 and 0.53 mA cm-2), respectively. Remarkably, after the i-t test of up to 100,000s and the accelerated durability test of 1500 cycles, 81.22% and 68.54% of the initial mass activity are well retained, respectively. The lattice distortion-associated local tensile strain as demonstrated by increased Pt-Pt bond length enhances ethanol adsorption and reduces reaction barriers. The upshift d-band center promotes ethanol oxidation and anti-CO capability of the catalysts. Moreover, hysteresis diffusion effect induced by lattice distortion in the HEA nanodendrites contributes to their superb ethanol oxidation stability. In-situ infrared absorption spectroscopy reveals that the three HEA nanodendrites mainly follow C1 pathway with C-C bond breaking to form CO followed by CO oxidation especially at a wide range of high potentials.

Zn and Cl Coregulated MXene Catalyst Enhances Li-CO2 Battery Reversibility.

MXenes are promising cathodes for Li-CO2 batteries owing to their high electrical conductivity and efficient CO2 activation function. However, the effects of adsorption and electronic structures of MXene on the full life cycle of Li-CO2 batteries have been rarely investigated. Here, we employ a coregulation approach to enhance the adsorption-decomposition of lithium carbonate (Li2CO3) by introducing Zn and Cl surface groups onto the Ti3C2 MXene (Zn-Ti3C2Cl2) catalyst. The incorporation of Cl surface groups enhances Li2CO3 adsorption on the MXene catalyst surface, resulting in the formation of small-sized and uniform Li2CO3. Additionally, the introduction of Zn shifts the d-band centers of titanium and promotes CO2 evolution reaction (CO2ER) activity, thereby facilitating the decomposition of discharge products. As a result, the Li-CO2 battery based on the Zn-Ti3C2Cl2 catalyst exhibits an ultralow overpotential (0.72 V) at 200 mA g-1 and stable cycling for up to 1500 h. This work validates the efficacy of promoting reversibility in Li-CO2 batteries by adjusting the adsorption-decomposition process.

Smart Compositional Design of B-Site Ordered Double Perovskite for Advanced Oxygen Catalysis at Ultra-High Current Densities.

Perovskite oxides have been considered promising oxygen catalysts foroxygen reduction and evolution reactions (ORR and OER), owing to structural and compositional flexibility, and tailorable properties. Ingenious B-site ordered La1.5Sr0.5NiMn0.5Fe0.5O6 (LSNMF) double perovskite is strategically designed by simultaneously interposing Ni0.5Mn0.5 and Ni0.5Fe0.5 into B' and B″ sites. Controlling B-site cation systematically tailors the electronic structure of the B-site cation with a d-band center (Md) upshift close to the Fermi level, increasing the overlap of the Md center and O 2p center (OP). The strong interaction of Md and Op facilitates the adsorption of oxygen and activates the lattice oxygen to participate in the OER process, thereby enhancing the ORR and OER activity. For ORR, LSNMF exhibited an onset potential of 0.9V along with a high limiting current of -8.05mAcm-2. At the same time, for OER at 1m KOH, LSNMF effectively reached a maximum current density of 3000mAcm-2. Most importantly, the difference between EORR (at -1mAcm-2) and EOER (at 10mAcm-2), ΔE is 0.69V, which stands among the best of recently reported perovskites. The as-designed LSNMF is stable, efficient, lucrative, and a promising candidate for practical application.