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Water is the only available fossil-free source of hydrogen. Splitting water electrochemically is among the most used techniques, however, it accounts for only 4% of global hydrogen production. One of the reasons is the high cost and low performance of catalysts promoting the oxygen evolution reaction (OER). Here, we report a highly efficient catalyst in acid, that is, solid-solution Ru‒Ir nanosized-coral (RuIr-NC) consisting of 3 nm-thick sheets with only 6 at.% Ir. Among OER catalysts, RuIr-NC shows the highest intrinsic activity and stability. A home-made overall water splitting cell using RuIr-NC as both electrodes can reach 10 mA cm −2 geo at 1.485 V for 120 h without noticeable degradation, which outperforms known cells. Operando spectroscopy and atomic-resolution electron microscopy indicate that the high-performance results from the ability of the preferentially exposed {0001} facets to resist the formation of dissolvable metal oxides and to transform ephemeral Ru into a long-lived catalyst. Ru is one of the most active metals for oxygen evolution reaction, but it quickly dissolves in acidic electrolyte particularly in nanosized form. Here, the authors show that coral-like solid-solution Ru‒Ir consisting of 3 nm-thick sheets with only 6 at% Ir is a long-lived catalyst with high activity.

The sluggish kinetics of Volmer step in the alkaline hydrogen evolution results in large energy consumption. The challenge that has yet well resolved is to control the water adsorption and dissociation. Here, we develop biaxially strained MoSe 2 three dimensional nanoshells that exhibit enhanced catalytic performance with a low overpotential of 58.2 mV at 10 mA cm −2 in base, and long-term stable activity in membrane-electrode-assembly based electrolyser at 1 A cm −2 . Compared to the flat and uniaxial-strained MoSe 2 , we establish that the stably adsorbed OH engineer on biaxially strained MoSe 2 changes the water adsorption configuration from O-down on Mo to O-horizontal on OH* via stronger hydrogen bonds. The favorable water dissociation on 3-coordinated Mo sites and hydrogen adsorption on 4-coordinated Mo sites constitute a tandem electrolysis, resulting in thermodynamically favorable hydrogen evolution. This work deepens our understanding to the impact of strain dimensions on water dissociation and inspires the design of nanostructured catalysts for accelerating the rate-determining step in multi-electron reactions. Hydroxide is the most abundant anion in alkaline solutions, but its impact on alkaline water electrolysis remains unclear. Herein, the authors report a biaxial strain induced OH engineer on MoSe 2 to accelerate alkaline hydrogen evolution by modifying the water dissociation.

High-entropy alloys (HEAs) are promising catalysts particularly adept for reactions involving multiple intermediates and requiring multifunctional active sites. However, conventional syntheses often result in either (kinetically) random-mixing HEA or (thermodynamically) phase-separated composites-both fail to fine-tune local structures and further optimizing their performances. Here we present finely tailoring the local ensembles in HEA catalysts through rational composition design and sequential pulsed annealing. Employing PdSnFeCoNi HEA as a model, pulsed annealing (e.g., 0.5 s heating at 1300 K for 30 cycles) leverages differences in enthalpic interactions and surface energies to control the formation of ultrafine PdSn clusters within the HEA matrix, yielding the heterostructured HEA/c-PdSn. Compared with random HEAs and commercial Pd/C, HEA/c-PdSn exhibits >5 − 10-fold higher mass activity and good stability (>90.6% retention after 2000 cycles) for ethanol oxidation. This enhancement arises from the synergy between active local ensembles and the multifunctional HEA matrix, which reduces overall limiting potential, mitigates sluggish C-C/C-H breaking, and enhances structural stabilization. Our findings provide a strategy for engineering heterostructured HEAs for broad catalytic applications. Local structure control is challenging in high entropy alloy (HEA) catalysts. Here, the authors report finely tailoring the local clustering in HEA catalysts through rational composition design and sequential pulse annealing, achieving enhanced activity and stability for ethanol electrooxidation.

The structure-performance relationship for single atom catalysts has remained unclear due to the averaged coordination information obtained from most single-atom catalysts. Periodic array of single atoms may provide a platform to tackle this inaccuracy. Here, we develop a data-driven approach by incorporating high-throughput density functional theory computations and machine learning to screen candidates based on a library of 1248 sites from single atoms array anchored on biaxial-strained transition metal dichalcogenides. Our screening results in Au atom anchored on biaxial-strained MoSe 2 surface via Au-Se 3 bonds. Machine learning analysis identifies four key structural features by classifying the ΔG H* data. We show that the average band center of the adsorption sites can be a predictor for hydrogen adsorption energy. This prediction is validated by experiments which show single-atom Au array anchored on biaxial-strained MoSe 2 archives 1000 hour-stability at 800 mA cm -2 towards acidic hydrogen evolution. Moreover, active hotspot consisting of Au atoms array and the neighboring Se atoms is unraveled for enhanced activity. The structure-performance relationship of single-atom catalysts remains unclear. Here a data-driven approach with high-throughput DFT and machine learning is used to screen 1248 single atoms arrays, to provide a better understanding of the hydrogen evolution reaction mechanism.

Binary solid-solution alloys generally adopt one of three principal crystal lattices—body-centred cubic (bcc), hexagonal close-packed (hcp) or face-centred cubic (fcc) structures—in which the structure is dominated by constituent elements and compositions. Therefore, it is a significant challenge to selectively control the crystal structure in alloys with a certain composition. Here, we propose an approach for the selective control of the crystal structure in solid-solution alloys by using a chemical reduction method. By precisely tuning the reduction speed of the metal precursors, we selectively control the crystal structure of alloy nanoparticles, and are able to selectively synthesize fcc and hcp AuRu 3 alloy nanoparticles at ambient conditions. This approach enables us to design alloy nanomaterials with the desired crystal structures to create innovative chemical and physical properties. The crystal structure of a solid-solution alloy is generally determined by its elemental composition, limiting synthetic control over the alloy’s properties. Here, the authors are able to selectively control the crystal structure of Au–Ru alloy nanoparticles by rationally tuning the reduction speed of the metal precursors.

FeM (M = Se, Te) chalcogenides have been well studied as promising magnets and superconductors, yet their potential as electrocatalysts is often considered limited due to anion dissolution and oxidation during electrochemical reactions. Here, we show that by using two-dimensional (2D) FeTeSe nanosheets, these conventionally perceived limitations can be leveraged to enable the reaction-driven in-situ generation of anisotropic in-plane tensile and out-of-plane compressive strains during the alkaline low-concentration nitrate reduction reaction (NO 3 − RR). The reconstructed catalyst demonstrates enhanced performance, yielding ammonia with a near-unity Faradaic efficiency and a high yield rate of 42.14 ± 2.06 mg h −1 mg cat −1 . A series of operando synchrotron-based X-ray measurements and ex-situ characterizations, alongside theoretical calculations, reveal that strain formation is ascribed to chalcogen vacancies created by partial Se/Te leaching, which facilitate the adsorption and dissociation of OH − /NO 3 − from the electrolyte, resulting in an O(H)-doped strained lattice. Combined electrochemical and computational investigations suggest that the superior catalytic performance arises from the synergistic contributions from the exposed strained Fe sites and surface hydroxyl groups. These findings highlight the potential of 2D transition metal chalcogenides for in-situ structural engineering during electrochemical reactions to enhance catalytic activity for NO 3 − RR and beyond. To overcome limitations with anion dissolution, the authors design 2D FeTeSe nanosheets as electrocatalyst. The reaction-driven, in-situ generation of anisotropic in-plane tensile and out-of-plane compressive strains enhances the alkaline low-concentration nitrate reduction.

Pd nanocubes (NCs) enclosed by six {100} facets are fascinating model materials for both fundamental studies and practical applications. However, the only available method to prepare well-defined sub-10 nm Pd NCs was developed by Xia et al. more than 10 years ago, unavoidably using polyvinylpyrrolidone (PVP) polymer to prevent particle aggregation. The strongly adsorbed PVP extremely deteriorates the catalysts’ efficiency because of the high coverage of accessible surface-active sites. Numerous efforts have been devoted to replacing PVP with weaker capping agents but with limited progress predominately due to the difficulties in tuning the growth kinetics of Pd NCs. For the first time, we report that macrocycle cucurbit[6]uril (CB[6]) can replace PVP in the synthesis of Pd NCs by dedicatedly controlling the growth parameters. CB[6] capped Pd NCs showed 1.1–1.5 times increased specific surface area compared to the surfactant-free commercial Pd catalysts. Moreover, X-ray photoelectron spectroscopy demonstrated the modified electronic structure of Pd NCs through the carbonyl group of CB[6]. Consequently, compared to the commercial catalysts, the obtained Pd NCs exhibited 7 times higher current density towards ethanol oxidation reaction. Remarkably, after 17 h of continuous work, it reduced deactivation by up to 1–4 orders of magnitude.

Heterogeneous single-atom catalysts (SACs) have gained significant attention for their maximized atom utilization and well-defined active sites, but they often struggle with multi-stage organic cross-coupling reactions due to limited coordination space and reactivity. Here, we report an “anchoring-borrowing” strategy combined facet engineering to develop artful single-atom catalysts (ASACs) through anchoring foreign single atoms onto specific facets of the non-innocent reducible carriers. ASACs exhibit adaptive coordination, effectively bypassing the oxidative-addition prerequisite for bivalent elevation at a single metal site in both homogenous and heterogeneous cross-couplings. For example, Pd 1 -CeO 2 (110) ASAC exhibits unparalleled activity in coupling with more accessible aryl chlorides, and challenging heterocycles, outperforming traditional catalysts with a remarkable turnover number of 45,327,037. Mechanistic studies reveal that ASACs leverage dynamic structural changes, with reducible carriers acting as electron reservoirs, significantly lowering reaction barriers. Furthermore, ASACs enable efficient synthesis of biologically significant compounds, drug intermediates, and active pharmaceutical ingredients (APIs) through a scalable high-speed circulated flow synthesis, underscoring great potential for sustainable fine chemical manufacturing. Heterogeneous single-atom catalysts (SACs) offer high atom utilization and well-defined active sites but face challenges in multi-stage cross-couplings due to limited coordination and reactivity. Here, the authors introduce SACs on reducible carriers, enabling adaptive coordination to bypass oxidative addition in cross-couplings.

Pd and Ru are two key elements of the platinum-group metals that are invaluable to areas such as catalysis and energy storage/transfer. To maximize the potential of the Pd and Ru elements, significant effort has been devoted to synthesizing Pd-Ru bimetallic materials. However, most of the reports dealing with this subject describe phase-separated structures such as near-surface alloys and physical mixtures of monometallic nanoparticles (NPs). Pd-Ru alloys with homogenous structure and arbitrary metallic ratio are highly desired for basic scientific research and commercial material design. In the past several years, with the development of nanoscience, Pd-Ru bimetallic alloys with different architectures including heterostructure, core-shell structure and solid-solution alloy were successfully synthesized. In particular, we have now reached the stage of being able to obtain Pd-Ru solid-solution alloy NPs over the whole composition range. These Pd-Ru bimetallic alloys are better catalysts than their parent metal NPs in many catalytic reactions, because the electronic structures of Pd and Ru are modified by alloying. In this review, we describe the recent development in the structure control of Pd-Ru bimetallic nanomaterials. Aiming for a better understanding of the synthesis strategies, some fundamental details including fabrication methods and formation mechanisms are discussed. We stress that the modification of electronic structure, originating from different nanoscale geometry and chemical composition, profoundly affects material properties. Finally, we discuss open issues in this field.

Catalytic conversion of the syngas into higher alcohols (HAs) via Fischer–Tropsch (F–T) synthesis is essential due to the widespread applications of HAs. The interfaces of cobalt and cobalt carbide (Co2C) are found to efficiently promote the HAs formation. However, the study on the links between structural evolution of Co–Co2C interfaces and HAs production is still lacking. In this work, Co3O4 with different contents of sodium (Na) as promoters was synthesized and high-pressure F–T reaction (3 MPa) was carried out in the aim of accelerating the Co2C formation and tuning the interfaces of Co–Co2C. XRD, (HR)TEM, ICP, XPS and XAFS were conducted to study the relationship between the variations of Co–Co2C interfaces and HAs production. With the increasing Na contents, the ratios of Co to Co2C decreased as revealed by XAFS and the selectivity of HAs was decreasing. The fitting results from EXAFS revealed that the ratio of Co to Co2C is in direct proportion to the selectivity of HAs. This work provides a theoretical guidance to tune the interfaces of Co–Co2C and improve the HAs production in F–T reaction.