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An in situformed IrOx(x≤ 2) layer driven by anodic bias serves as the essential active site of Ir-based materials for oxygen evolution reaction (OER) electrocatalysis. Once being confined to atomic thickness, such an IrOxlayer possesses both a favorable ligand effect and maximized active Ir sites with a lower O-coordination number. However, limited by a poor understanding of surface reconstruction dynamics, obtaining atomic layers of IrOxremains experimentally challenging. Herein, we report an idea of material design using intermetallic IrVMn nanoparticles to induce in situformation of an ultrathin IrOxlayer (O-IrVMn/IrOx) to enable the ligand effect for achieving superior OER electrocatalysis. Theoretical calculations predict that a strong electronic interaction originating from an orderly atomic arrangement can effectively hamper the excessive leaching of transition metals, minimizing vacancies for oxygen coordination. Linear X-ray absorption near edge spectra analysis, extended X-ray absorption fine structure fitting outcomes, and X-ray photoelectron spectroscopy collectively confirm that Ir is present in lower oxidation states in O-IrVMn/IrOxdue to the presence of unsaturated O-coordination. Consequently, the O-IrVMn/IrOxdelivers excellent acidic OER performances with an overpotential of only 279 mV at 10 mA cm–2and a high mass activity of 2.3 A mg–1at 1.53 V (vs RHE), exceeding most Ir-based catalysts reported. Moreover, O-IrVMn/IrOxalso showed excellent catalytic stability with only 0.05 at. % Ir dissolution under electrochemical oxidation, much lower than that of disordered D-IrVMn/IrOx(0.20 at. %). Density functional theory calculations unravel that the intensified ligand effect optimizes the adsorption energies of multiple intermediates involved in the OER and stabilizes the as-formed catalytic IrOxlayer.

Potassium-ion hybrid capacitors (PIHCs) are in principle advantageous over the traditional metal-ion hybrid capacitors (MIHCs) in terms of low cost, safety, and reliability, holding enormous potential for the massive market, yet they remain largely an uncharted field. Herein, we provide a comprehensive review of recent advances on PIHCs, including fundamental understanding, device configurations, and design rationale. Then, technical hurdles that essentially impede the development of PIHCs are discussed, accompanied by corresponding improvement strategies for all aspects of PIHCs. Lastly, how far we are from the lab bench to the consumer market is highlighted, and a comprehensive roadmap starting from cooperative components integration and ending with the future direction of next-generation PIHCs for grid-scale energy storage is clearly described. We anticipate that this review will timely arouse strong interest and attention from both academic and industrial communities to this rising technology and make a revolutionary step forward toward commercial applications.

Proton exchange membrane water electrolysis (PEMWE) is promising for the sustainable and scalable production of green hydrogen, yet it is now technologically limited by the high loading of precious Ir in the anodic catalyst layer (CL). Herein, we report a kind of anodic CL composed of hierarchical IrRu sub-nanosheets on nanowires for boosting the operational efficiency of PEM electrolyzers. Integrating this hierarchical CL into PEMWE with a low Ir loading of 0.35 mgIrcm−2, we demonstrated an outstanding water electrolysis performance—a hydrogen production current density of 1.0 A cm−2at 1.65 V, along with a high overload current density of 6.0 A cm−2. In particular, the PEMWE could operate stably at 2.0 A cm−2for more than 240 h. We further demonstrated the application of our designed PEMWE in a commercial hydrogen generator with a high H2generation rate of ∼300 mL min−1.

Potassium–sulfur (K–S) batteries are severely limited by the sluggish kinetics of the solid-phase conversion of K2S3/K2S2to K2S, the rate-determining and performance-governing step, which urgently requires a cathode with facilitated sulfur accommodation and improved catalytic efficiency. To this end, we leverage the orbital-coupling approach and herein report a strong d−π coupling catalytic configuration of single-atom Co anchored between two alkynyls of graphdiyne (Co-GDY). The d−π orbital coupling of the Co–C4moiety fully redistributes electrons two-dimensionally across the GDY, and as a result, drastically accelerates the solid-phase K2S3/K2S2to K2S conversion and enhances the adsorption of sulfur species. Applied as the cathode, the S/Co-GDY delivered a record-high rate performance of 496.0 mAh g–1at 5 A g–1in K–S batteries. In situand ex situcharacterizations coupling density functional theory (DFT) calculations rationalize how the strong d−π orbital coupling of Co–C4configuration promotes the reversible solid-state transformation kinetics of potassium polysulfide for high-performance K–S batteries.

Metallene materials with atomic thicknesses are receiving increasing attention in electrocatalysis due to ultrahigh surface areas and distinctive surface strain. However, the continuous strain regulation of metallene remains a grand challenge. Herein, taking advantage of autocatalytic reduction of Cu2+on biaxially strained, carbon-intercalated Ir metallene, we achieve control over the carbon extraction kinetics, enabling fine regulation of carbon intercalation concentration and continuous tuning of (111) in-plane (−2.0%–2.6%) and interplanar (3.5%–8.8%) strains over unprecedentedly wide ranges. Electrocatalysis measurements reveal the strain-dependent activity toward hydrogen evolution reaction (HER), where weakly strained Ir metallene (w-Ir metallene) with the smallest lattice constant presents the highest mass activity of 2.89 A mg–1Irat −0.02 V vs reversible hydrogen electrode (RHE). Theoretical calculations validated the pivotal role of lattice compression in optimizing H binding on carbon-intercalated Ir metallene surfaces by downshifting the d-band center, further highlighting the significance of strain engineering for boosted electrocatalysis.

Li–O2batteries (LOBs) are considered as one of the most promising energy storage devices due to their ultrahigh theoretical energy density, yet they face the critical issues of sluggish cathode redox kinetics during the discharge and charge processes. Here we report a direct synthetic strategy to fabricate a single-atom alloy catalyst in which single-atom Pt is precisely dispersed in ultrathin Pd hexagonal nanoplates (Pt1Pd). The LOB with the Pt1Pd cathode demonstrates an ultralow overpotential of 0.69 V at 0.5 A g–1and negligible activity loss over 600 h. Density functional theory calculations show that Pt1Pd can promote the activation of the O2/Li2O2redox couple due to the electron localization caused by the single Pt atom, thereby lowering the energy barriers for the oxygen reduction and oxygen evolution reactions. Our strategy for designing single-atom alloy cathodic catalysts can address the sluggish oxygen redox kinetics in LOBs and other energy storage/conversion devices.

Over the past several decades, extensive efforts have been undertaken to find methods to synthesize advanced electrocatalysts that possess rationally controllable sizes, shapes, crystallinities, compositions and structures for efficient energy conversion technologies. Of these methods, the one-pot seedless synthetic method in aqueous solution at ambient temperature has attracted extensive attention from researchers because it is a simple, inexpensive, energy-efficient, safe and less toxic method for the synthesis of electrocatalytic nanomaterials. In this review, recent developments in one-pot seedless synthetic strategies for the design of various structures of Au, Pt, Pd, Ag and multimetallic nanocrystals in aqueous solutions at ambient temperatures will be introduced, primarily focusing on the structure–electrocatalytic performance relationships of the as-prepared metal nanocrystals. Current challenges and outlooks for future research directions will also be provided in this promising research field.

Quantum computational chemistry has emerged as a potential application of quantum computing. Hybrid quantum-classical computing methods, such as variational quantum eigensolvers, have been designed as promising solutions to quantum chemistry problems. Nonetheless, challenges due to theoretical complexity and experimental imperfections hinder progress in achieving reliable and accurate results. Experimental works for solving electronic structures are consequently still restricted to non-scalable or classically simulable ansatz or limited to a few qubits with large errors. Here, we address the critical challenges associated with solving molecular electronic structures using noisy quantum processors. Our protocol presents improvements in the circuit depth and running time, key metrics for chemistry simulation. Through systematic hardware enhancements and the integration of error-mitigation techniques, we overcome theoretical and experimental limitations and successfully scale up the implementation of variational quantum eigensolvers with an optimized unitary coupled cluster ansatz to 12 qubits. We produce high-precision results of the ground-state energy for molecules with error suppression by around two orders of magnitude. Our work demonstrates a feasible path towards a scalable solution to electronic structure calculation.

Structurally ordered L10-PtM (M = Fe, Co, Ni and so on) intermetallic nanocrystals, benefiting from the chemically ordered structure and higher stability, are one of the best electrocatalysts used for fuel cells. However, their practical development is greatly plagued by the challenge that the high-temperature (>600 °C) annealing treatment necessary for realizing the ordered structure usually leads to severe particle sintering, morphology change and low ordering degree, which makes it very difficult for the gram-scale preparation of desirable PtM intermetallic nanocrystals with high Pt content for practical fuel cell applications. Here we report a new concept involving the low-melting-point-metal (M′ = Sn, Ga, In)-induced bond strength weakening strategy to reduce Eaand promote the ordering process of PtM (M = Ni, Co, Fe, Cu and Zn) alloy catalysts for a higher ordering degree. We demonstrate that the introduction of M′ can reduce the ordering temperature to extremely low temperatures (≤450 °C) and thus enable the preparation of high-Pt-content (≥40 wt%) L10-Pt-M-M′ intermetallic nanocrystals as well as ten-gram-scale production. X-ray spectroscopy studies, in situ electron microscopy and theoretical calculations reveal the fundamental mechanism of the Sn-facilitated ordering process at low temperatures, which involves weakened bond strength and consequently reduced Eavia Sn doping, the formation and fast diffusion of low-coordinated surface free atoms, and subsequent L10nucleation. The developed L10-Ga-PtNi/C catalysts display outstanding performance in H2–air fuel cells under both light- and heavy-duty vehicle conditions. Under the latter condition, the 40% L10-Pt50Ni35Ga15/C catalyst delivers a high current density of 1.67 A cm−2at 0.7 V and retains 80% of the current density after extended 90,000 cycles, which exceeds the United States Department of Energy performance metrics and represents among the best cathodic electrocatalysts for practical proton-exchange membrane fuel cells.

Although dispersing Pt atomic clusters (ACs) on a conducting support is a promising way to minimize the Pt amount required in hydrogen evolution reaction (HER), the catalytic mass activity and durability of Pt ACs are often unsatisfactory for alkaline HER due to their unfavorable water dissociation and challenges in stabilizing them against agglomeration and detachment. Herein, we report a class of single-atom Cr–N4sites with high oxophilicity interfaced with Pt ACs on mesoporous carbon for achieving a highly active and stable alkaline HER in an anion-exchange-membrane water electrolyzer (AEMWE). The as-made catalyst achieves the highest reported Pt mass activity (37.6 times higher than commercial Pt/C) and outstanding operational stability. Experimental and theoretical studies elucidate that the formation of a unique Pt–Cr quasi-covalent bonding interaction at the interface of Cr–N4sites and Pt ACs effectively suppresses the migration and thermal vibration of Pt atoms to stabilize Pt ACs and contributes to the greatly enhanced catalytic stability. Moreover, oxophilic Cr–N4sites adjacent to Pt ACs with favorable adsorption of hydroxyl species facilitate nearly barrierless water dissociation and thus enhance the HER activity. An AEMWE using this catalyst (with only 50 μgPtcm–2) can operate stably at an industrial-level current density of 500 mA cm–2at 1.8 V for >100 h with a small degradation rate of 90 μV h–1.

Metal-isolated clusters (MICs) physically confined on photoactive materials are of great interest in the field of photosynthesis of hydrogen peroxide (H2O2). Despite recent important endeavors, weak confinement of MICs in the reported photocatalytic systems leads to their low catalytic activity and stability. Herein, we report a new strategy of fluorinated covalent organic frameworks (COFs) to strongly confine Pd ICs for greatly boosting the photocatalytic activity and stability of H2O2photosynthesis. Both experimental and theoretical results reveal that strong electronegative fluorine can increase the metal–support interaction and optimize the d-band center of Pd ICs, thus significantly enhancing the stability and activity of photocatalytic H2O2. An optimal TAPT-TFPA COFs@Pd ICs photocatalyst delivers a stable H2O2yield rate of 2143 μmol h–1g–1. Most importantly, the as-made TAPT-TFPA COFs@Pd ICs exhibit high catalytic stability over 100 h, which is the best among the reported materials.

Scalable generation of genuine multipartite entanglement with an increasing number of qubits is important for both fundamental interest and practical use in quantum-information technologies1,2. On the one hand, multipartite entanglement shows a strong contradiction between the prediction of quantum mechanics and local realization and can be used for the study of quantum-to-classical transition3,4. On the other hand, realizing large-scale entanglement is a benchmark for the quality and controllability of the quantum system and is essential for realizing universal quantum computing5–8. However, scalable generation of genuine multipartite entanglement on a state-of-the-art quantum device can be challenging, requiring accurate quantum gates and efficient verification protocols. Here we show a scalable approach for preparing and verifying intermediate-scale genuine entanglement on a 66-qubit superconducting quantum processor. We used high-fidelity parallel quantum gates and optimized the fidelitites of parallel single- and two-qubit gates to be 99.91% and 99.05%, respectively. With efficient randomized fidelity estimation9, we realized 51-qubit one-dimensional and 30-qubit two-dimensional cluster states and achieved fidelities of 0.637 ± 0.030 and 0.671 ± 0.006, respectively. On the basis of high-fidelity cluster states, we further show a proof-of-principle realization of measurement-based variational quantum eigensolver10for perturbed planar codes. Our work provides a feasible approach for preparing and verifying entanglement with a few hundred qubits, enabling medium-scale quantum computing with superconducting quantum systems.

Transition metal hydrides represent an emerging class of high-efficiency catalysts for hydrogen-involving reactions but suffer from insufficient thermodynamic stability. This preview highlights an excellent example of constructing an ambient-stable two-dimensional transition hydride in which the surface ligand plays the key role.

Designing nanozymes that match natural enzymes have always been an attractive and challenging goal. In general, researchers mainly focus on the construction of metal centers and the control of non-metallic ligands of nanozyme to regulate their activities. However, this is not applicable to lactate oxidase, i.e., flavoenzymes with flavin mononucleotide (FMN)-dependent pathways. Herein, we propose a coordination strategy to mimic lactate oxidase based on engineering the electronic properties at the N center by modulating the Co number near N in the Cox–N nanocomposite. Benefitting from the manipulated coordination fields and electronic structure around the electron-rich N sites, Co4N/C possesses a precise recognition site for lactate and intermediate organization and optimizes the absorption energies for intermediates, leading to superior oxidation of the lactate α-C–sp(3)–H bond toward ketone. The optimized nanozyme delivers much improved anticancer efficacy by reversing the high lactate and the immunosuppressive state of the tumor microenvironment, subsequently achieving excellent tumor growth and distant metastasis inhibition. The developed Co4N/C NEs open a new window for building a bridge between chemical catalysis and biocatalysis.

Carrier migration path and driving forces are two crucial factors for charge separation of heterojunction with efficient photoelectric response from the thermodynamic and kinetic perspectives, respectively. Constructing the S-scheme heterojunction and achieving an efficient migration path for space charge separation have aroused great interest, while a thorough insight into tuning interfacial band bending for S-scheme heterojunction is absent. Herein, we report a class of Zn atom-doped CeO2/g-C3N4heterostructure for achieving a new carrier migration path conversion from inferior type-II to advanced S-scheme. Zn-dependent volcano-type plot for Zn-CeO2is established to tune the Fermi level of CeO2. The built-in electric field for carrier flow dynamics strengthens when coupling with g-C3N4, which significantly boosts the photoelectric response. Based on the intrinsic enzymelike activity of Zn-CeO2, we further demonstrate that the Zn-CeO2/g-C3N4S-scheme heterojunction can be explored for constructing a sensitive nanozymatic photoelectrochemical biosensor for the detection of acetylcholinesterase.

Photocorrosion of highly active photocatalysts is an urgent problem to be solved in the field of photocatalysis; however, searching for effective strategies for inhibiting photocorrosion of photocatalysts is still a grand challenge. Herein, we design and construct a class of Cu2O/2D PyTTA-TPA COFs (PyTTA: 1,3,6,8-Tetrakis(4-aminophenyl)pyrene,

Great efforts have been made to expand the application fields of nanozymes, which puts forward requirements for nanozymes with both superior catalytic activity and specificity. Herein, we reported the high-indexed intermetallic Pt3Sn (H–Pt3Sn) with high peroxidase-like activity and specificity. The resultant H–Pt3Sn exhibits a specific activity of 345.3 U/mg, which is 1.82 times higher than Pt. Moreover, H–Pt3Sn possesses negligible oxidase-like and catalase-like activities, achieving superior catalytic specificity toward H2O2activation. Experimental and theoretical calculations reveal both the splitting energy for adsorbed H2O2and the energy barrier for the rate-determining step of H–Pt3Sn are significantly decreased compared with Pt3Sn and Pt. Finally, a nanozyme-linked immunosorbent assay is successfully developed, achieving the sensitive and accurate colorimetric detection for carcinoembryonic antigen with a low detection limit of 0.49 pg/mL and showing practical feasibility in serum sample detection.

High-entropy alloys (HEAs) hold great promise for efficient catalyst discovery in a virtually unlimited compositional space. The controllable incorporation of multiple metal elements into low-dimensional nanomaterials with tailored structure merits untold scientific and applicable potential; however, it remains a great challenge using previous high-temperature synthetic techniques. Hence, we report a general reduction-diffusion method for constructing a library of atomic-thick Pt-based HEA nanowires (NWs) with up to ten components. We have identified that the initial formation of Pt NWs and the nucleation rate of other transition metals are the key points in forming a uniform HEA single-phase solid solution. Our method can be used to synthesize 26 kinds of multimetallic NWs, including 17 HEAs. The high-entropy design can introduce severe lattice distortion in NWs, thereby altering the strain distribution and electronic structure, which enables the HEA NWs with specific components to exhibit outstanding catalytic performance in hydrogen oxidation reaction and hydrogen evolution reaction.

Photocatalytic aerobic oxidation desulfurization (PAODS) is a promising and sustainable alternative to conventional, energy-intensive desulfurization techniques for petroleum products. However, its development is greatly plagued by the low capability in generating highly reactive oxygen species and sluggish kinetics of sulfide oxidation of reported photocatalysts. Here we report a class of MoOxnanocluster decorated on ultrathin Mo-doped TiO2nanosheet (MoOx/MoTiO) catalyst for efficiently facilitating the photocatalytic aerobic oxidation of sulfides. We demonstrate that MoOx/MoTiO can not only promote the generation of highly reactive singlet oxygen (1O2) but also enhance the aerobic conversion of sulfides, which leads to a record dibenzothiophene oxidation activity of 3.90 mmol g−1h−1. The multiple experimental characterizations and density functional theory calculations collectively reveal that the doped-Mo sites can interact with the photogenerated excitons, enabling directly energy transfer generation of 1O2through a new exciton modulation mechanism, and the coordination unsaturated MoOxclusters play the role of co-catalyst to enhance the separation of charge carriers, and effectively catalyze the reaction between sulfides and 1O2to form sulfones.

The sluggish reaction kinetics and poor structure stability of transition metal dichalcogenides (TMDs)-based anodes in potassium-ion batteries (KIBs) usually cause limited rate performance and rapid capacity decay, which seriously impede their application. Herein, we report a vacancy engineering strategy for preparing a class of Te-doped 1T’-ReSe2anchored onto MXene (Te-ReSe2/MXene) as an advanced anode for KIBs with high performance. By taking advantage of the synergistic effects of the defective Te-ReSe2arrays with expanded interlayers and the elastic MXene nanosheets with self-autoadjustable function, the Te-ReSe2/MXene superstructure exhibits boosted K+ion storage performance, in terms of high reversible capacity (361.1 mA h g−1at 0.1 A g−1over 200 cycles), excellent rate capability (179.3 mA h g−1at 20 A g−1), ultra-long cycle life (202.8 mA h g−1at 5 A g−1over 2000 cycles), and steady operation in flexible full battery, presenting one of the best performances among the TMDs-based anodes reported thus far. The kinetics analysis and theoretical calculations further indicate that satisfactory pseudocapacitive property, high electronic conductivity and outstanding K+ion adsorption/diffusion capability corroborate the accelerated reaction kinetics. Especially, structural characterizations clearly elaborate that the Te-ReSe2/MXene undergoes reversible evolutions of an initial insertion process followed by a conversion reaction.

Noble metal based nanozymes show great potential in replacing natural enzymes; however, their development is greatly restricted by their relatively low specificity and activity. Herein, we report the synthesis of a class of amorphous/crystalline PtRuTe nanomaterials with a Pt/Te-enriched core and a Ru-enriched shell as efficient peroxidase mimics with selectively enhanced peroxidase-like activity and suppressed oxidase-like activity. We demonstrate that amorphous domains play a critical role in tuning and optimizing the catalytic properties. The PtRuTe nanozyme with high-percentage defects exhibits superior catalytic activities and kinetics, and the suppressed oxidase-like activity could diminish the interference of O2in the glucose colorimetric assay. The high catalytic performance can be caused by amorphous phase induced electron redistribution and electronic interactions between different elements and the synergistic effect of multimetallic nanocrystals. The concurrent extraordinary peroxidase-like activity and suppressed oxidase-like activity guarantee the amorphous/crystalline PtRuTe nanozymes as promising alternatives of natural enzymes for biosensing and beyond.

In dual‐band shared‐aperture base station antennas, the secondary radiation (SR) field caused by cross‐band couplings always leads to radiation pattern distortion. In this work, the SR field caused by the coupling is attributed to the excitation of the target high‐order modes from the perspective of the characteristic mode. To effectively suppress the target modes, L‐shaped slots are proposed to load the arms of the radiator and altering the current paths. As compared with conventional dipoles without L‐shaped slots, the proposed antenna generates less SR field. Therefore, the radiation pattern of the high‐band antennas keeps stable in a dual‐band shared‐aperture antenna array environment. Prototype of a dual‐band antenna array consisting of the proposed low‐band (LB) antenna and a 4 × 4 high‐band (HB) antenna array is fabricated. Simulated and measured results show that the designed dual‐band array operates at both 0.74–0.82 GHz and 3.30–3.80 GHz. The experimental results verify that the cross‐band decoupling has been achieved with the high‐order mode suppression.

Aqueous zinc-ion batteries (AZIBs) are attractive energy storage devices that benefit from improved safety and negligible environmental impact. The V2O5-based cathodes are highly promising, but the dissolution of vanadium is one of the major challenges in realizing their stable performance in AZIBs. Herein, we design a Ti3C2TxMXene layer on the surface of V2O5nanoplates (VPMX) through a van der Waals self-assembly approach for suppressing vanadium dissolution during an electrochemical process for greatly boosting the zinc-ion storage performance. Unlike conventional V2O5/C composites, we demonstrate that the VPMX hybrids offer three distinguishable features for achieving high-performance AZIBs: (i) the MXene layer on cathode surface maintains structural integrity and suppresses V dissolution; (ii) the heterointerface between V2O5and MXene enables improved host electrochemical kinetics; (iii) reduced electrostatic repulsion exists among host layers owing to the lubricating water molecules in the VPMX cathode, facilitating interfacial Zn2+diffusion. As a result, the as-made VPMX cathode shows a long-term cycling stability over 5000 cycles, surpassing other reported V2O5-based materials. Especially, we find that the heterointerface between V2O5and MXene and lubricated water molecules in the host can achieve an enhanced rate capability (243.6 mAh g–1at 5.0 A g–1) for AZIBs.

A flexible fiber-shaped Zn-MnO2battery is fabricated using a low-cost, scalable, and efficient continuous wet spinning technique and displays high electrochemical performance.

The estimation of high dimensional covariance matrices is an interesting and important research topic for many empirical time series problems such as asset allocation. To solve this dimension dilemma, a factor structure has often been taken into account. This paper proposes a dynamic factor structure whose factor loadings are generated in reproducing kernel Hilbert space (RKHS), to capture the dynamic feature of the covariance matrix. A simulation study is carried out to demonstrate its performance. Four different conditional variance models are considered for checking the robustness of our method and solving the conditional heteroscedasticity in the empirical study. By exploring the performance among eight introduced model candidates and the market baseline, the empirical study from 2001 to 2017 shows that portfolio allocation based on this dynamic factor structure can significantly reduce the variance, i.e., the risk, of portfolio and thus outperform the market baseline and the ones based on the traditional factor model.

High-entropy alloys (HEAs) are attracting intensive attention due to their broad compositional tunability and interesting catalytic properties. However, precisely shaping the HEAs into suprathin low-dimensional nanostructures for achieving diverse applications remains an enormous challenge owing to their intrinsic thermodynamic instability. Herein we propose a new and general low-temperature method for incorporating up to eight metallic elements into one single-phase subnanometer ribbon to achieve the thinnest HEA metal materials in the world. We experimentally demonstrate that synthetic processes for suprathin HEA subnanometer ribbons (SNRs) include (1) different metal atom nucleation via galvanic exchange reaction between different metal precursors and Ag nanowire template, (2) co-reduction of different metal precursors on nanowire template, and (3) the removal of the inner Ag core. Density functional theory (DFT) calculations reveal that the crystallization and stabilization of HEA SNRs strongly depend on the “highly dynamic” Ag from the template, and the crystallization levels of HEA subnanometer ribbons are closely correlated with the concentration of Pt and Pd. We demonstrate that the present synthetic method enables the flexible control of components and concentrations in HEAs SNRs for achieving a library of HEA SNRs and also superior electrocatalytic properties. The well-designed HEA SNRs show great improvement in catalyzing the oxygen reduction reaction of fuel cells and also high discharge capacity, low charge overpotential, and excellent durability for Li–O2batteries. DFT calculations reveal the superior electrochemical performances are attributed to the strong reduction capability from high-concentration reductive elements in HEAs, while the other elements guarantee the site-to-site efficient electron transfer.

Luminol-based electrochemiluminescence (ECL) can be readily excited by various reactive oxygen species (ROS) electrogenerated with an oxygen reduction reaction (ORR). However, the multiple active intermediates involved in the ORR catalyzed with complex nanomaterials lead to recognizing the role of ROS still elusive. Moreover, suffering from the absence of the direct electrochemical oxidation of luminol at the cathode and poor transformation efficiency of O2to ROS, the weak cathodic ECL emission of luminol is often neglected. Herein, owing to the tunable coordination environment and structure-dependent catalytic feature, single-atom catalysts (SACs) are employed to uncover the relationship between the intrinsic ORR activity and ECL behavior. Interestingly, the traditionally negligible cathodic ECL of luminol is first boosted (ca. 70-fold) owing to the combination of electrochemical ORR catalyzed via SACs and chemical oxidation of luminol. The boosted cathodic ECL emission exhibits electron-transfer pathway-dependent response by adjusting the surrounding environment of the center metal atoms in a controlled way to selectively produce different active intermediates. This work bridges the relationship between ORR performance and ECL behavior, which will guide the development of an amplified sensing platform through rational tailoring of the ORR activity of SACs and potential-resolved ECL assays based on the high-efficiency cathodic ECL reported.

The creation and precise analysis of novel Fe-N-C atomic architecture with an optimal electronic structure are important for oxygen reduction reaction (ORR) electrocatalysis. In this issue of Chem Catalysis, Li’s group reports a class of square-pyramidal Fe-N4active sites with superior ORR performance derived from two-tier fine-tuning of the electronic structure via well-characterized defect-modulated O-coordination structures.

We propose a novel factor-based regularized covariance matrix estimator when the number of factors is large compared to the sample size and derive the convergence rates of our estimator. Empirical results demonstrate our proposed estimator performs well in finite samples. [ABSTRACT FROM AUTHOR]

Binary metal chalcogenides (BMCs) have shown better electrochemical performance compared with their mono metal counterparts owing to their abundant phase interfaces, higher active sites, faster electrochemical kinetics and higher electronic conductivity. Nevertheless, their performance still undergoes adverse decline during electrochemical processes mainly due to poor intrinsic ionic conductivities, large volume expansions, and structural agglomeration and fracture. To tackle these problems, various strategies have been applied to engineer the BMC nanostructures to obtain optimized electrode materials. However, the lack of understanding of the electrochemical response of BMCs still hinders their large-scale application. This review not only highlights the recent progress and development in the preparation of BMC-based electrode materials but also explains the kinetics to further understand the relation between structure and performance. It will also explain the engineering of BMCs through nanostructuring and formation of their hybrid structures with various carbonaceous materials and three-dimensional (3D) templates. The review will discuss the detailed working mechanism of BMC-based nanostructures in various electrochemical energy storage (EES) systems including supercapacitors, metal-ion batteries, metal-air batteries, and alkaline batteries. In the end, major challenges and prospective solutions for the development of BMCs in EES devices are also outlined. We believe that the current review will provide a guideline for tailoring BMCs for better electrochemical devices.

The development of high-performance electrocatalysts for hydrogen evolution reaction (HER) is of great significance for green, sustainable, and renewable energy conversion. Herein, we report the synthesis of amorphous Ru clusters on Co-doped defect-rich hollow carbon nanocage (a-Ru@Co-DHC) as an efficient electrocatalyst for HER in the basic media. Due to the advantages such as high surface area, rich edge defect, atomic Co doping and amorphous Ru clusters, the as-made a-Ru@Co-DHC displays an efficient HER performance with a near-zero onset overpotential, a low Tafel slope (62 mV dec−1), a low overpotential of 40 mV at 10 mA cm−2and high stability, outperforming the commercial Ru nanocrystal/C, commercial Pt/C, and other reported Ru-based catalysts. This work provides a new insight into designing new metal doped carbon nanocages catalysts supported by amorphous nanoclusters for achieving the enhanced electrocatalysis.

Atomic sites co-catalyst (ASC) on photocatalytic materials possesses an attractive prospect to promote charge carrier separation and tune surface reaction kinetics, yet the synthesis of earth-abundant ASC under low temperature remains a great challenge. Here, a novel in-situNH4+-etched strategy to anchor atomic Mo sites on ZnIn2S4hierarchical nanotubes (HNTs) with abundant mesopores under mild conditions for promoting charge carrier separation and enhancing light multi-reflections is developed for efficient photocatalytic H2evolution. Density functional theory calculations and linear sweep voltammetry demonstrate that the well-defined Mo-S2O1sites with distinctive coordination configuration and electronic property contribute to the enhanced separation of photo-generated charge carriers and reduced Gibbs free energy for H2evolution. Consequently, the well-defined MoSA-ZIS HNTs present an excellent photocatalytic activity with a rate of 29.9 µmol h−1(5.98 mmol g−1h−1), which is 7.3 times higher than that of ZnIn2S4nanosheets (NSs), to be among the best ZnIn2S4-based photocatalysts. The present strategy breaks the high-temperature limitation of conventional top-down thermal dissociation/emitting approach for anchoring non-noble metal atomic sites on catalyst support.

Because of the favorable mass transport and increased available active sites, the rational design and preparation of porous carbon structures are essential but still challenging. Herein, a novel and facile supramolecular anchoring strategy was developed to achieve the embedding of ruthenium (Ru) nanoparticles in N-doped mesoporous carbon nanospheres through pyrolyzing the precursor formed by coordination assembly between metal ions and zinc gluconate (G(Zn)). Featuring rich hydroxyl groups, the G(Zn) can effectively chelate Ru3+via metal-oxygen bonds to form 3D supramolecular nanospheres, and meanwhile, mesopores in carbon nanospheres were expanded after subsequent pyrolysis thanks to the volatilization of zincic species at high temperature. As a demonstration, the best-performing catalyst displayed extraordinary activity for the hydrogen evolution reaction (HER) with a small overpotential of 43 mV versus reversible hydrogen electrode (vs RHE) at 10 mA/cm2and a Tafel slope of 39 mV/dec, which was superior to that of commercial Pt/C in alkaline medium. Theoretical calculations revealed that the catalytic activity was significantly promoted by the strong electronic coupling between Ru nanoparticles and N-doped porous carbon, which increased the electron transfer capability and facilitated the adsorption and dissociation of H2O to realize an efficient HER.

Exploring a new strategy for the removal of adsorbed CO (CO*) on a Pt surface at a low potential is the key to achieving enhanced catalysis for the formic acid oxidation reaction (FAOR); however, the development of such a strategy remains a significant challenge. Herein, we report a class of Au/PtCo heterojunction nanowires (HNWs) as efficient electrocatalysts for accelerating the FAOR. This heterojunction structure and the induced Co alloying effects can facilitate formic acid adsorption/activation on Pt with high CO tolerance, generating the FAOR pathway from dehydration to dehydrogenation. The optimized Au23/Pt63Co14HNWs showed the highest specific and mass activities of 11.7 mA cm−2Ptand 6.42 A mg−1Ptreported to date, respectively, which are considerably higher than those of commercial Pt/C. DFT calculations confirmed that the electron-rich Au segment enhances the electronic activity of the PtCo NWs, which not only allows the construction of a highly efficient electron transfer channel for the FAOR but also suppresses CO formation.

Potassium-ion batteries (KIBs) are emerging as the prospective alternatives to lithium-ion batteries in energy storage systems owing to the sufficient resources and relatively low cost of K-related materials. However, serious volume expansion and low specific capacity are found in most materials systems resulting from the large intrinsic radius of K+. Herein, SnS2nanosheets anchored on nitrogen and sulfur co-doped MXene (SnS2NSs/MXene) are creatively designed as advanced anode materials for KIBs. SnS2NSs/MXene with a unique hierarchical structure can not only provide fast transmission channels for K+but also avoid the accumulation of K+and volume expansion. These novel features make SnS2NSs/MXene electrodes exhibit a superior reversible specific capacity of 342.4 mA h g–1under 50 mA g–1. Also, they maintain 206.1 mA h g–1at an even higher current density of 0.5 A g–1over 800 cycles almost without capacity decay. Moreover, the multistep alloying reaction mechanism of SnS2NSs/MXene composites and K+is revealed by the ex situX-ray diffraction measurement. In addition, the density functional theory calculations confirm the existence of Ti–S bonds between SnS2nanosheets and MXene, which significantly enhance the structural stability and cycling electrochemical performance of SnS2NSs/MXene composites.

With the merits of low cost, abundant resources, environment friendliness, and high energy density, the Li-S battery is recognized as a promising alternative to the Li ion battery and is anticipated to play an important role in high-energy-density electrochemical storage systems. In this review, we first review the development process of Li-S batteries and briefly introduce the working principle of Li-S batteries. The scientific problems existing in the Li-S batteries, such as sulfur cathode, separator, electrolyte, and Li anode, and the corresponding countermeasures, are then summarized. Subsequently, main research advancements of Li-S batteries are comprehensively reviewed, and the critical concerns about commercialization of Li-S batteries are discussed. Finally, we give our perspectives on the development of high-performance Li-S batteries. We hope this review can provide the timely and comprehensive information on the future research direction of Li-S batteries and offer the guidance for material design and structure optimization of Li-S batteries.

A novel 3D star-like MOF derived single atom catalyst with unique Co-N3C coordination can efficiently decrease the free energy of rate determining step, which exhibits excellent ORR activity in both alkaline and acid medium.

The volumetric density of the metal atomic site is decisive to the operating efficiency of the photosynthetic nanoreactor, yet its rational design and synthesis remain a grand challenge. Herein, we report a shell-regulating approach to enhance the volumetric density of Co atomic sites onto/into multishell ZnxCd1–xS for greatly improving CO2photoreduction activity. We first establish a quantitative relation between the number of shell layers, specific surface areas, and volumetric density of atomic sites on multishell ZnxCd1–xS and conclude a positive relation between photosynthetic performance and the number of shell layers. The triple-shell ZnxCd1–xS–Co1achieves the highest CO yield rate of 7629.7 μmol g–1h–1, superior to those of the double-shell ZnxCd1–xS–Co1(5882.2 μmol g–1h–1) and single-shell ZnxCd1–xS–Co1(4724.2 μmol g–1h–1). Density functional theory calculations suggest that high-density Co atomic sites can promote the mobility of photogenerated electrons and enhance the adsorption of Co(bpy)32+to increase CO2activation (CO2→ CO2* → COOH* → CO* → CO) viathe S–Co-bpy interaction, thereby enhancing the efficiency of photocatalytic CO2reduction.

Lithium–sulfur batteries are considered potential high-energy-density candidates to replace current lithium-ion batteries. However, several problems remain to be solved, including low conductivity, huge volume change, and a severe shuttle effect on the cathode side, as well as inevitable lithium dendrites on the anode side. Rare earth compounds, which play vital roles in various industries, show latent capacity as cathode hosts or interlayers to tackle the inherent problems of lithium–sulfur batteries. However, the application of rare earth compounds in lithium–sulfur batteries has not been reviewed so far, despite they showing obvious advantages for tuning polysulfide retention and conversion. In this mini-review, we start by introducing the concept of lithium–sulfur batteries and providing background information on rare earth-based materials. In the main body, we explore rare earth compounds as cathode hosts or interlayers, then discuss various types of each. Finally, we offer an outlook on the existing challenges and possible opportunities for using rare earth compounds as cathode hosts or interlayers for lithium–sulfur batteries.

Single-atom nanozyme-based catalytic therapy is of great interest in the field of tumor catalytic therapy; however, their development suffers from the low affinity of nanozymes to the substrates (H2O2or O2), leading to deficient catalytic activity in the tumor microenvironment. Herein, we report a new strategy for precisely tuning the d-band center of dual-atomic sites to enhance the affinity of metal atomic sites and substrates on a class of edge-rich N-doped porous carbon dual-atomic sites Fe–Mn (Fe1Mn1–NCe) for greatly boosting multiple-enzyme-like catalytic activities. The as-made Fe1Mn1–NCeachieved a much higher catalytic efficiency (Kcat/Km= 4.01 × 105S–1·M–1) than Fe1–NCe(Kcat/Km= 2.41 × 104S–1·M–1) with an outstanding stability of over 90% activity retention after 1 year, which is the best among the reported dual-atom nanozymes. Theoretical calculations reveal that the synergetic effect of Mn upshifts the d-band center of Fe from −1.113 to −0.564 eV and enhances the adsorption capacity for the substrate, thus accelerating the dissociation of H2O2and weakening the O–O bond on O2. We further demonstrated that the superior enzyme-like catalytic activity of Fe1Mn1–NCecombined with photothermal therapy could effectively inhibit tumor growth in vivo, with an inhibition rate of up to 95.74%, which is the highest value among the dual-atom artificial enzyme therapies reported so far.

Developing low-cost and efficient electrocatalysts to accelerate oxygen evolution reaction (OER) kinetics is vital for water and carbon-dioxide electrolyzers. The fastest-known water oxidation catalyst, Ni(Fe)OxHy, usually produced through an electrochemical reconstruction of precatalysts under alkaline condition, has received substantial attention. However, the reconstruction in the reported catalysts usually leads to a limited active layer and poorly controlled Fe-activated sites. Here, we demonstrate a new electrochemistry-driven F-enabled surface-reconstruction strategy for converting the ultrathin NiFeOxFynanosheets into an Fe-enriched Ni(Fe)OxHyphase. The activated electrocatalyst shows a low OER overpotential of 218 ± 5 mV at 10 mA cm–2and a low Tafel slope of 31 ± 4 mV dec–1, which is among the best for NiFe-based OER electrocatalysts. Such superior performance is caused by the effective formation of the Fe-enriched Ni(Fe)OxHyactive-phase that is identified by operandoRaman spectroscopy and the substantially improved surface wettability and gas-bubble-releasing behavior.

Rationally designing the core/shell architecture of Pt-based electrocatalysts has been demonstrated as an effective way to induce a surface strain effect for promoting the sluggish kinetics of the oxygen reduction reaction (ORR) at the cathode of fuel cells. However, unstable core dissolution and structural collapse usually occur in Pt-based core/shell catalysts during the long-term cycling operation, greatly impacting actual fuel cell applications. Impeding the dissolution of cores beneath the Pt shells is the key to enhancing the catalytic stability of materials. Herein, a method for sandwiching atomic PdAu interlayers into one-dimensional (1D) Pd/Pt core/shell nanowires (NWs) is developed to greatly boost the catalytic stability of subnanometer Pt shells for ORR. The Pd/PdAu/Pt core/shell/shell NWs display only 7.80% degradation of ORR mass activity over 80 000 potential cycles with no dissolution of Pd cores and good preservation of the holistic sandwich core/shell nanostructures. This is a significant improvement of electrocatalytic stability compared with the Pd/Pt core/shell NWs, which deformed and inactivated over 80 000 potential cycles. The density functional theory (DFT) calculations further demonstrate that the electron-transfer bridge Pd and electron reservoir Au, serving in the PdAu atomic interlayer, both guarantee the preservation of the high electroactivity of surface Pt sites during the long-term ORR stability test. In addition, the Pd/PdAu/Pt NWs show a 1.7-fold higher mass activity (MA) for ORR than the conventional Pd/Pt NWs. The enhanced activity can be attributed to the strong interaction between PdAu interlayers and subnanometer-Pt shells, which suppresses the competitive Pd-4d bands and boosts the surface Pt-5d bands toward the Fermi level for higher electroactivity, proved from DFT.

Cobalt carbonate hydroxide hydrate (CCHH) has long been functioning merely as a precursor to prepare compound catalysts; however, its intrinsic potential for the oxygen evolution reaction (OER) is quite limited due to its poor catalytic activity. Herein, a concept has been proposed to solve this issue by doping Fe into CCHH nanowires grown on nickel foam (denoted as Fe-CCHH/NF) for achieving efficient OER catalysis by electrochemical transformation. The obtained Fe-CCHH/NF-30 exhibits OER catalytic performance with an overpotential of only 200 mV versus the reversible hydrogen electrode (vs. RHE) at a current density of 10 mA cm–2and small Tafel slope of 50 mV dec–1in 1 M KOH. Moreover, it displays stability for over 130 h at a large current density of 55 mA cm–2, and no activity decline is observed after the 3000 cycle test. The performance of Fe-CCHH/NF-30 renders it one of the most promising OER catalysts. The density functional theory calculation reveals that the doped Fe can greatly enhance the OER activity by lowering the reactive energy barrier.

Pd–Pt bimetallic nanocrystals have become appealing in the electrocatalytic field by virtue of their synergy effects derived from the electronic coupling between two metals. Herein, a facile seed-mediated growth approach is reported for synthesis of Pt-on-Pd dendritic nanosheets (DNSs) through the growth of Pt branches on ultrathin Pd nanosheets (NSs). The as-obtained Pt-on-Pd DNSs exhibit superior catalytic activity toward both oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR), with mass activities (MAs) 2.2 times higher for ORR and 3.4 times higher for MOR than commercial Pt/C catalysts. Moreover, these spatially separated Pt branches supported on 2D NSs also endow the Pt-on-Pd DNSs with impressive durability for ORR with only 18.9% loss in MA, whereas the Pt/C catalyst loses 50.0% after 10,000-cycle accelerated durability tests. This 2D DNS architecture can be extended to other 2D metallic NS substrates for constructing Pt-based electrocatalysts with excellent electrocatalytic performance.

The aprotic Li-CO2battery with high energy density is an attractive energy-storage technology. However, its development is largely impeded by the sluggish kinetics of CO2reduction and evolution reactions. Here, we demonstrate a class of ultrathin triangular RuRh alloy nanosheets as an exceptionally active catalyst for greatly accelerating the kinetics of CO2reduction and evolution reactions and achieving a high-performance Li-CO2battery. The RuRh alloy nanosheets-based battery can achieve the lowest voltage gap of 1.35 V during the charge-discharge process and stably cycle for 180 cycles with a cutoff capacity of 1,000 mAh g−1at 1,000 mA g−1. Density functional theory calculations demonstrate the pivotal roles of Rh introduction in RuRh alloy nanosheets, which evidently activate the electron-transfer ability of surface Ru and balance the CO2binding near Ru sites. We find that the d-d correlation between Rh and Ru contributes to the energetically favorable cycle of the Li-CO2battery.

Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries (SIBs) due to their high theoretical capacity and low cost. However, they deliver unsatisfactory performance in practice, owing to their intrinsically low conductivity, sluggish kinetics and volume expansion during the charge-discharge process. Herein, we demonstrate the synthesis of SnSe2nanocrystals coupled with hierarchical porous carbon (SnSe2NCs/C) microspheres for boosting SIBs in terms of capacity, rate ability and durability. The unique structure of SnSe2NCs/C possesses several advantages, including inhibiting the agglomeration of SnSe2nanoparticles, relieving the volume expansion, accelerating the diffusion kinetics of electrons/ions, enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite. As a result, the as-obtained SnSe2NCs/C microspheres show a high reversible capacity (565 mA h g−1after 100 cycles at 100 mA g−1), excellent rate capability, and long cycling life stability (363 mA h g−1at 1 A g−1after 1000 cycles), which represent the best performances among the reported SIBs based on SnSe2-based anode materials.

Developing enzyme-free sensors with high sensitivity and selectivity for H2O2and glucose is highly desirable for biological science. Especially, it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors. Herein, we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes (Co3O4/NCNTs) hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air. The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2reduction in neutral solutions and glucose oxidation in alkaline solutions. As sensor electrode, the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2response with a sensitivity of 87.40μA (mmol/L)−1cm−2, a linear range of 5.00μmol/L–11.00mmol/L, and a detection limitation of 1μmol/L in H2O2detection, and a good glucose detection performance with 5μmol/L. These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.

Developing efficient water-splitting electro-catalysts with high mass activity is in urgent need for large-scale sustainable production of hydrogen but, still remains as a big challenge. Herein, we report a one-pot method to fabricate a series of core@shell Ni@RuM (M=Ni or Co) nanocrystals (NCs) with Ni as the core and tunable RuM (M=Ni or Co) as the alloy shell for efficient water-splitting catalysis. Among these core@shell NCs, the obtained Ni@RuNi NCs exhibit the highest intrinsic activity for hydrogen evolution reaction (HER) and possess an outstanding mass activity of 1590 mA mgRu−1at 0.07 V vs.reversible hydrogen electrode (RHE), which is 1.7 times higher than that of commercial Pt/C (950 mA mgPt−1). As for oxygen evolution reaction (OER), the prepared Ni@Ru0.4Co0.6NCs with optimized shell composition achieve more enhanced mass activity of 270 mA mgRu−1at 1.56 V vs.RHE, approaching three times higher than that of commercial RuO2(89 mA mgRu−1). The superb mass activity of these Ni@RuM (M=Ni or Co) NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell.