A facile heterogeneous interface-induced topological phase transition method has been demonstrated to synthesize cobalt/nitrogen-doped carbon with unbalanced double primitive bicontinuous architecture.

We present a micelle-assisted self-assembly strategy for synthesizing covalent organic framework (COF) helical hollow nanoribbons by using achiral monomers and surfactants. The process involves polymerization of nanowires within rod-like micelle cores, followed by their attachment to form helical nanoribbons and solvothermal crystallization to create hollow COF architectures. This method allows for the controllable synthesis of COF helical nanostructures with tunable pitch and morphology and can be extended to other COF helical architectures by variation of the amine monomer. This strategy provides new insights into designing COF helical nanostructures using achiral building blocks within micellar systems.

Efficient regeneration of spent LiFePO4 is essential for the sustainable management of end-of-life electric vehicle batteries, given their significant market share. A universal method capable of directly regenerating spent LiFePO4 from cells with varying states of health is crucial for practical implementation. Herein, we developed an oxalic acid/lithium hydroxide-based regeneration approach that effectively restores mixed spent LiFePO4, achieving a high specific capacity of 163.1 mA h g-1 at 0.1C.

Anisotropic hierarchically porous metal-organic frameworks (MOFs) with asymmetric morphologies hold great promise for improving the utilization efficiency of the MOF matrix, thereby expanding their applicability. However, imparting MOFs with precisely controlled porous architectures and morphologies remains challenging. Here, an ingenious soft/hard matter phase transition co-mediated assembly strategy is developed to mimic the biomineralization process for synthesizing anisotropic UiO-66-NH2 mesoporous nanobowls (UiO-66-NH2 mesoNBs). This process relies on in situ generated amorphous lamellar anionic surfactant/Zr-oxo cluster complexes as metal sources and templates. This is followed by the slow decomposition of complexes and the co-assembly of ternary mixed micelles and MOF precursors on their surfaces, creating crystalline UiO-66-NH2 mesoNBs with cylindrical mesochannels. The phase transition from lamellar to cylindrical mesophases is co-driven by changes in the packing parameters caused by the "soft" surfactant reorganization and variations in the charge density of the "hard" framework during crystallization from amorphous Zr-oxo clusters to the crystalline MOF matrix. By varying the surfactant ratios, UiO-66-NH2 can form diverse novel nanostructures and achieve well-tailored pore sizes within the small mesoporous range. This work provides fundamental insights into the transformation processes in amphiphilic molecule-directed MOF biomimetic mineralization and offers a promising strategy for constructing anisotropic hierarchically porous MOFs with high structural tunability.

Crystal phase engineering of metal nanocatalysts presents a promising strategy to modulate the catalyst-adsorbate interaction for enhanced catalysis. However, conventional synthetic methods have faced substantial challenges in achieving regulatable crystal phases and lack precise control over catalyst composition at the atomic level, which is detrimental, especially for reactions involving multiple intermediates. Here, we report a facile strategy for simultaneously regulating the crystal phase and composition (Pt single-atom alloying) of ultrathin Ru nanocages (<2 nm in thickness), enabling efficient hydrogen evolution reaction (HER) in alkaline electrolytes. In situ characterizations and theoretical calculations reveal that both the metastable face-centered cubic (fcc) Ru phase and isolated Pt atoms contribute to stabilizing metallic Ru, facilitating Pt-Ru synergy for optimized adsorption of H* and *OH intermediates and accelerated HER kinetics. Consequently, the Pt-Rufcc single-atom alloy nanocages exhibit impressive alkaline HER performance, with an overpotential as low as 8.5 mV at 10 mA cm-2, an 18.0-fold enhancement in mass activity relative to commercial Pt/C and commendable stability over 400 h of operation at ampere-level current densities. This work provides insights into the atomic-level design and preparation of metal nanocrystals with unconventional phases for advanced catalysts.

Hollow multi-shell covalent organic frameworks (COFs) with abundant modular interfaces, high loading capacity, and various microenvironments are expected to hold great potential for chemical separation, heterogeneous catalysis, and energy storage/conversion. However, the synthetic methodology of COF hollow multi-shell nanoarchitectures has not been established. Herein, we demonstrate an ingenious "crystallinity wave"-induced regional difference ripening strategy to synthesize a series of hollow multi-shell COF particles with controllable shell numbers and shell thickness. The methodology relies on the isolation effect of the local crystalline COF thin layer inserted between the two layers of amorphous covalent organic polymer by the short-time Ostwald ripening, so that different regions of the particles exhibit distinct reaction stages before reaching chemical equilibrium in the subsequent dynamic imine exchange reaction, and then regions that tend to hydrolyze dissolve during the complete ripening process to form a hollow multi-shell structure. Remarkably, this strategy can be extended to prepare other hollow multi-shell COFs by altering monomers. As a proof-of-concept application, the obtained hollow multi-shell COFs are used as the electrode materials for supercapacitor. Benefiting from the short mass transfer path of the hollow multi-shell structure, ordered channels of the COF, and their high surface area, the as-prepared particles exhibit remarkably enhanced specific capacitance.

Developing electrochemical energy storage and conversion devices (e.g., water splitting, regenerative fuel cells and rechargeable metal-air batteries) driven by intermittent renewable energy sources holds a great potential to facilitate global energy transition and alleviate the associated environmental issues. However, the involved kinetically sluggish oxygen evolution reaction (OER) severely limits the entire reaction efficiency, thus designing high-performance materials toward efficient OER is of prime significance to remove this obstacle. Among various materials, cost-effective perovskite oxides have drawn particular attention due to their desirable catalytic activity, excellent stability and large reserves. To date, substantial efforts have been dedicated with varying degrees of success to promoting OER on perovskite oxides, which have generated multiple reviews from various perspectives, e.g., electronic structure modulation and heteroatom doping and various applications. Nonetheless, the reviews that comprehensively and systematically focus on the latest intellectual design strategies of perovskite oxides toward efficient OER are quite limited. To bridge the gap, this review thus emphatically concentrates on this very topic with broader coverages, more comparative discussions and deeper insights into the synthetic modulation, doping, surface engineering, structure mutation and hybrids. More specifically, this review elucidates, in details, the underlying causality between the being-tuned physiochemical properties [e.g., electronic structure, metal-oxygen (M-O) bonding configuration, adsorption capacity of oxygenated species and electrical conductivity] of the intellectually designed perovskite oxides and the resulting OER performances, coupled with perspectives and potential challenges on future research. It is our sincere hope for this review to provide the scientific community with more insights for developing advanced perovskite oxides with high OER catalytic efficiency and further stimulate more exciting applications.

Transition metal-nitrogen-carbon complexes, featuring single metal atoms embedded in a nitrogen-doped carbon matrix, emerge as promising alternatives to traditional platinum-based catalysts, offering cost-effectiveness, abundance, and enhanced catalytic performance. This work introduces a novel method for the etching and doping of zeolitic imidazolate frameworks (ZIFs) with transition metals, creating a uniform distribution of secondary metal centers on ZIF surfaces. By disrupting the crystalline symmetry of ZIFs through synthetic defect engineering, we gain access to their entire internal volume, creating multichannel pathways. The absorption of metal ions is theoretically simulated, demonstrating their thermodynamically spontaneous nature. The selective removal of defect channels under Lewis acidic conditions, induced by metal ion alcoholysis/hydrolysis, facilitates the introduction of metal atoms into ZIF cavities. The resulting single-atom catalyst, after pyrolysis, features a three-dimensional (3D) multichannel structure, high surface area, and uniformly dispersed metal atoms within the N-doped carbon matrix, establishing it as an exceptional catalyst for the oxygen reduction reaction (ORR). Our findings highlight the potential of using metal etching in defect-engineered metal-organic frameworks (MOFs) for single-atom catalyst preparation, paving the way for the next generation of high-performance, cost-effective ORR catalysts in sustainable energy systems.

Two-dimensional (2D) hierarchically porous metal-organic framework (MOF) nanoarchitectures with tailorable meso-/macropores hold great promise for enhancing mass transfer kinetics, augmenting accessible active sites, and thereby boosting performance in heterogeneous catalysis. However, achieving the general synthesis of 2D free-standing MOF nanosheets with controllable hierarchical porosity and thickness remains a challenging task. Herein, we present an ingenious "hard" emulsion-induced interface super-assembly strategy for preparing 2D hierarchically porous UiO-66-NH2 nanosheets with highly accessible pore channels, tunable meso-/macropore sizes, and adjustable thicknesses. The methodology relies on transforming the geometric shape of oil droplet templates within appropriate oil-in-water emulsions from conventional zero-dimensional (0D) "soft" liquid spheres to 2D "hard" solid sheets below the oil's melting/freezing point. Subsequent surfactant exchange on the surface of 2D "hard" emulsions facilitates the heterogeneous nucleation and interfacial super-assembly of in situ formed mesostructured MOF nanocomposites, serving as structural units, in a loosely packed manner to produce 2D MOF nanosheets with multimodal micro/meso-/macroporous systems. Importantly, this strategy can be extended to prepare other 2D hierarchically porous MOF nanosheets by altering metal-oxo clusters and organic ligands. Benefiting from fast mass transfer and highly accessible Lewis acidic sites, the resultant 2D hierarchically porous UiO-66-NH2 nanosheets deliver a fabulous catalytic yield of approximately 96% on the CO2 cycloaddition of glycidyl-2-methylphenyl ether, far exceeding the yield of approximately 29% achieved using conventional UiO-66-NH2 microporous crystals. This "hard" emulsion-induced interface super-assembly strategy paves a new path toward the rational construction of elaborate 2D nanoarchitecture of hierarchical MOFs with tailored physicochemical properties for diverse potential applications.

Single Atoms Catalysts (SACs) have emerged as a class of highly promising heterogeneous catalysts, where the traditional bottom-up synthesis approaches often encounter considerable challenges in relation to aggregation issues and poor stability. Consequently, achieving densely dispersed atomic species in a reliable and efficient manner remains a key focus in the field. Herein, we report a new facile electrochemical knock-down strategy for the formation of SACs, whereby the metal Zn clusters are transformed into single atoms. While a defect-rich substrate plays a pivotal role in capturing and stabilizing isolated Zn atoms, the feasibility of this novel strategy is demonstrated through a comprehensive investigation, combining experimental and theoretical studies. Furthermore, when studied in exploring for potential applications, the material prepared shows a remarkable improvement of 58.21% for the Li+ storage and delivers a capacity over 300 Wh kg(-1) after 500 cycles upon the transformation of Zn clusters into single atoms.

Metal–organic frameworks (MOFs) have garnered significant attention in the field of catalysis due to their unique advantages such as diverse coordination geometry, variable metal nodes, and organic linkers, facilitating precise structural and compositional control for achieving programmable catalytic functionalities. Although their inherent microporous structure could provide excellent shape selectivity during catalysis, it typically impedes the mass transfer process, thereby reducing the use of internal active sites and overall catalytic efficiency. Additionally, employing single MOFs as catalysts presents challenges in achieving complex catalytic reactions that require multifunctional active sites. In recent years, considerable research efforts have focused on designing and constructing hierarchical nanostructured MOFs to alleviate substrate diffusion limitations by introducing secondary nanopores, shortening diffusion distances via the construction of low-dimensional nanoarchitectures, and constructing multifunctional catalysts by integrating distinct MOFs with suitable functions. This review provides a comprehensive overview of the design, synthesis methods, and formation mechanisms of MOF-based hierarchical nanostructures in recent years. Subsequently, it further highlights their applications in thermal catalysis, electrocatalysis, and photocatalysis, along with the relationship between their hierarchical nanostructures and catalytic performances. Finally, it provides an outlook on the challenges and potential development directions of hierarchically structured MOF nanocatalysts.

In this study, we present a facile formic acid treatment to rejuvenate aged graphite anodes from spent lithium-ion batteries (LIBs) without damaging the electrode structure. This method effectively removes the interfacial blocking layer, improving capacity and rate performance. Our approach contributes to sustainable battery recycling strategies for spent graphite anodes in LIBs.

Direct formic acid fuel cells (DFAFCs) are among the promising energy sources in the future low-carbon economy. A key challenge hindering their scale-up and commercialization is the lack of efficient electrocatalysts for anodic formic acid oxidation (FAO). Very recently, the FAO performance of palladium hydrides (PdHx) has been found to be superior to the pristine Pd that is well known for its high intrinsic FAO activity. However, there is enormous space for the controlled synthesis and electrocatalytic behaviors of PdHx-based nanomaterials awaiting to be explored. Herein, the hydrogen intercalation-induced crystallization of PdNiP alloy nanoparticles is reported, and the obtained PdNiP-H nanoparticles exhibit excellent FAO performance. Of particular note, the FAO stability of PdNiP-H is much better than that of pristine Pd-H. Furthermore, the PdNiP-H nanoparticles are used as the anode catalyst in a prototype DFAFC, which demonstrate much higher power density than commercial Pd/C. Density functional theory calculations show that the synergistic effect of alloying Ni and P endows the PdNiP-H with a higher preference toward FAO via the direct pathway and better anti-CO* poisoning capability. This work shines new light on the development of PdHx-based nanoalloys with good activity and stability for DFAFC applications.

Atomically dispersed single-atom catalysts are intriguing catalysts in the field of electrocatalysis for nearly 100% exploitation of metal atoms. However, they are still far from practical usage due to the scaling relationship limit and metal loading limit. Generation of a diatomic complex would offer superior catalytic performance through the cooperation of two neighboring atoms as active sites. Herein, Fe/Co dual atomic sites embedded in a tube-on-plate hollow structure are designed and fabricated for an efficient electrochemical oxygen reduction reaction (ORR). The unique structure composed of ultrathin nanotube building blocks dramatically maximizes the surface area for copious active site exposure. Thanks to the synergetic interaction between Fe/Co pairs, the obtained FeCo/NC exhibits outstanding ORR activity and stability in alkaline media. Furthermore, density functional theory calculations have revealed that the remarkable activity is attributed to the electron-deficient Fe sites in FeCoN6. This work may pave the way for the innovative design of highly dispersed dual-site catalysts for broader applications in the realm of electrochemical catalysis.

Exploring earth-abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi 2 S 4 yolk-shell spheres (P-CoNi 2 S 4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas-phase phosphorization strategy. Benefiting from the strengthened Ni 3+ /Ni 2+ couple, enhanced electronic conductivity, and hollow structure, the P-CoNi 2 S 4 YSSs exhibit excellent activity and durability towards hydrogen/oxygen evolution and urea oxidation reactions in alkaline solution, affording low potentials of −0.135 V, 1.512 V, and 1.306 V (versus reversible hydrogen electrode) at 10 mA cm −2 , respectively. Remarkably, when used as the anode and cathode simultaneously, the P-CoNi 2 S 4 catalyst merely requires a cell voltage of 1.544 V in water splitting and 1.402 V in urea electrolysis to attain 10 mA cm −2 with excellent durability for 100 h, outperforming most of the reported nickel-based sulfides and even noble-metal-based electrocatalysts. This work promotes the application of sulfides in electrochemical hydrogen production and provides a feasible approach for urea-rich wastewater treatment.

Prussian blue analogs (PBAs) are considered as reliable and promising cathode materials for aqueous Zn-ion batteries (AZIBs), but they suffer from low capacity and poor cycling stability due to insufficient active sites and structural damage caused by the ion insertion/extraction processes. Herein, a template-engaged ion exchange approach has been developed for the synthesis of Co-substituted Mn-rich PBA hollow spheres (CoMn-PBA HSs) as cathode materials for AZIBs. Benefiting from the multiple advantageous features including hollow structure, abundant active sites, fast Zn2+ ion diffusion, and partial Co substitution, the CoMn-PBA HSs electrode shows efficient zinc ion storage properties in terms of high capacity, decent rate capability and prolonged cycle life.

Non‐noble‐metal‐based nanomaterials can exhibit extraordinary electrocatalytic performance toward the oxygen evolution reaction (OER) by harnessing the structural evolution during catalysis and the synergistic effect between elements. However, the structure of active centers in bimetallic/multimetallic catalysts is under long‐time debate in the catalysis community. Here, an efficient bimetallic Ni–Fe selenide‐derived OER electrocatalyst is reported and the structure–activity correlation during the OER evolution studied. By combining experiments and theoretical calculations, a conceptual advance is provided, in that the local coordination structure distortion and disordering of active sites inherited from the pre‐catalyst and post‐formed by a further reconstruction are responsible for boosting the OER performance. The active center is identified on Ni sites showing moderate bindings with oxygenous intermediates rather than Fe sites with strong and poisonous adsorptions. These findings provide crucial understanding in manipulating the local coordination and electronic structures toward rational design and fabrication of efficient OER electrocatalysts.

Highly efficient electrocatalysts are essential for the production of green hydrogen from water electrolysis. Herein, a metal-organic framework-assisted pyrolysis-replacement-reorganization approach is developed to obtain ultrafine Pt-Co alloy nanoparticles (sub-10 nm) attached on the inner and outer shells of porous nitrogen-doped carbon nanotubes (NCNT) with closed ends. During the thermal reorganization, the migration of Pt-Co nano-alloys to both surfaces ensures the maximized exposure of active sites while maintaining the robust attachment to the porous carbon matrix. Density functional theory calculations suggest a nearly thermodynamically-neutral free energy of adsorption for hydrogen intermediates and diversified active sites induced by alloying, thus resulting in a great promotion in intrinsic activity towards the hydrogen evolution reaction (HER). Benefiting from the delicate structural design and compositional modulation, the optimized Pt 3 Co@NCNT electrocatalyst manifests outstanding HER activity and superior stability in both acidic and alkaline media.

Lithium metal has been considered as an ideal anode candidate for future high energy density lithium batteries. Herein, we develop a three-dimensional (3D) hybrid host consisting of Ag nanoparticle-embedded nitrogen-doped carbon macroporous fibers (denoted as Ag@CMFs) with selective nucleation and targeted deposition of Li. The 3D macroporous framework can inhibit the formation of dendritic Li by capturing metallic Li in the matrix as well as reducing local current density, the lithiophilic nitrogen-doped carbons act as homogeneous nucleation sites owing to the small nucleation barrier, and the Ag nanoparticles improve the Li nucleation and growth behavior with the reversible solid solution-based alloying reaction. As a result, the Ag@CMF composite enables a dendrite-free Li plating/stripping behavior with high Coulombic efficiency for more than 500 cycles. When this anode is coupled with a commercial LiFePO4 cathode, the assembled full cell manifests high rate capability and stable cycling life.