Unipolar Ionic Diode Nanofluidic Membranes Enabled by Stepped Mesochannels for Enhanced Salinity Gradient Energy Harvesting.

Developing ionic diode membranes featuring asymmetric structures is in high demand for salinity gradient energy harvesting. These membranes offer benefits in mitigating ion concentration polarization, thereby promoting ion permeability. However, most reported works focus on the role of heterogeneous charge-based bipolar ionic diode membranes for ion concentration polarization suppression, with comparatively less attention given to maintaining ion selectivity. Herein, unipolar ionic diode nanofluidic mesoporous silica membranes featuring stepped mesochannels were developed via a micellar sequential oriented interfacial self-assembly strategy as a salinity gradient energy harvester. Due to the asymmetric mesochannels and unipolar structure (both sides carry negative charge), the ionic diode membranes exhibit a strong rectification ratio of ∼15.91 to facilitate unidirectional ion transport while maintaining excellent cation selectivity (cation transfer number of ∼0.85). Besides, the vertically aligned mesochannels significantly reduce ion transport resistance, generating a high ionic flux. Consequently, the unipolar ionic diode nanofluidic membranes demonstrate a power output of 5.88 W/m2 between artificial sea and river water. The unipolar feature gives notable enhancements of 296% and 144% in power output compared to the symmetric membrane and bipolar ionic diode membrane, respectively. This work opens up new routes for designing ionic diode membranes for salinity gradient energy harvesting.

Ultrafine Asymmetric Soft/Stiff Nanohybrids with Tunable Patchiness via a Dynamic Surface-Mediated Assembly.

Asymmetric soft-stiff patch nanohybrids with small size, spatially separated organics and inorganics, controllable configuration, and appealing functionality are important in applications, while the synthesis remains a great challenge. Herein, based on polymeric single micelles (the smallest assembly subunit of mesoporous materials), we report a dynamic surface-mediated anisotropic assembly approach to fabricate a new type of small asymmetric organic/inorganic patch nanohybrid for the first time. The size of this asymmetric organic/inorganic nanohybrid is ∼20 nm, which contains dual distinct subunits of a soft organic PS-PVP-PEO single micelle nanosphere (12 nm in size and 632 MPa in Young' modulus) and stiff inorganic SiO2 nanobulge (∼8 nm, 2275 MPa). Moreover, the number of SiO2 nanobulges anchored on each micelle can be quantitatively controlled (from 1 to 6) by dynamically tuning the density (fluffy or dense state) of the surface cap organic groups. This small asymmetric patch nanohybrid also exhibits a dramatically enhanced uptake level of which the total amount of intracellular endocytosis is about three times higher than that of the conventional nanohybrids.

Ionic Pumping Effect at the Tailored Mesoporous Carbon Interface for an Extra-Stable Lithium Ion Battery at Low Temperatures.

Ion transportation at the interface significantly influences the electrochemical performance of the lithium ion battery, especially at high rates and low temperatures. Here, we develop a controlled self-assembly strategy for constructing a mesoporous carbon nanolayer with a uniform pore size and varied thicknesses on the two-dimensional monolayer MXene substrate. On the basis of the excellent electron conductivity of MXene, the mesoporous carbon layer is found with a voltage-driven ion accumulation effect, acting as an "ionic pump". The thicker mesoporous layer (∼2.28 nm) has the ability to accommodate a substantial quantity of ions, demonstrating enhanced ionic conductivity, remarkable cycling stability (192.8 mAh/g after 9400 cycles at 5.0 A/g), and outstanding rate capability at ambient and sub-zero temperatures (∼601 mAh/g at 0 °C and 0.05 A/g). This work provides valuable insights and guidance for the further development of high-performance electrode materials at high rates or low temperatures.

Hydrogen-Bonded Mesoporous Frameworks with Tunable Pore Sizes and Architectures from Nanocluster Assembly Units.

Construction of mesoporous frameworks by noncovalent bonding still remains a great challenge. Here, we report a micelle-directed nanocluster modular self-assembly approach to synthesize a novel type of two-dimensional (2-D) hydrogen-bonded mesoporous frameworks (HMFs) for the first time based on nanoscale cluster units (1.0-3.0 nm in size). In this 2-D structure, a mesoporous cluster plate with ∼100 nm in thickness and several micrometers in size can be stably formed into uniform hexagonal arrays. Meanwhile, such a porous plate consists of several (3-4) dozens of layers of ultrathin mesoporous cluster nanosheets. The size of the mesopores can be precisely controlled from 11.6 to 18.5 nm by utilizing the amphiphilic diblock copolymer micelles with tunable block lengths. Additionally, the pore configuration of the HMFs can be changed from spherical to cylindrical by manipulating the concentration of the micelles. As a general approach, various new HMFs have been achieved successfully via a modular self-assembly of nanoclusters with switchable configurations (nanoring, Keggin-type, and cubane-like) and components (titanium-oxo, polyoxometalate, and organometallic clusters). As a demonstration, the titanium-oxo cluster-based HMFs show efficient photocatalytic activity for hydrogen evolution (3.6 mmol g-1h-1), with a conversion rate about 2 times higher than that of the unassembled titanium-oxo clusters (1.5 mmol g-1h-1). This demonstrates that HMFs exhibited enhanced photocatalytic activity compared with unassembled titanium-oxo clusters units.

The Rise of Xene Hybrids.

Xenes, mono-elemental atomic sheets, exhibit Dirac/Dirac-like quantum behavior. When interfaced with other 2D materials such as boron nitride, transition metal dichalcogenides, and metal carbides/nitrides/carbonitrides, it enables them with unique physicochemical properties, including structural stability, desirable bandgap, efficient charge carrier injection, flexibility/breaking stress, thermal conductivity, chemical reactivity, catalytic efficiency, molecular adsorption, and wettability. For example, BN acts as an anti-oxidative shield, MoS2 injects electrons upon laser excitation, and MXene provides mechanical flexibility. Beyond precise compositional modulations, stacking sequences, and inter-layer coupling controlled by parameters, achieving scalability and reproducibility in hybridization is crucial for implementing these quantum materials in consumer applications. However, realizing the full potential of these hybrid materials faces challenges such as air gaps, uneven interfaces, and the formation of defects and functional groups. Advanced synthesis techniques, a deep understanding of quantum behaviors, precise control over interfacial interactions, and awareness of cross-correlations among these factors are essential. Xene-based hybrids show immense promise for groundbreaking applications in quantum computing, flexible electronics, energy storage, and catalysis. In this timely perspective, recent discoveries of novel Xenes and their hybrids are highlighted, emphasizing correlations among synthetic parameters, structure, properties, and applications. It is anticipated that these insights will revolutionize diverse industries and technologies.

Biomimetic Superstructured Interphase for Aqueous Zinc-Ion Batteries.

The practical application of aqueous zinc-ion batteries (AZIBs) is greatly challenged by rampant dendrites and pestilent side reactions resulting from an unstable Zn-electrolyte interphase. Herein, we report the construction of a reliable superstructured solid electrolyte interphase for stable Zn anodes by using mesoporous polydopamine (2D-mPDA) platelets as building blocks. The interphase shows a biomimetic nacre's "brick-and-mortar" structure and artificial transmembrane channels of hexagonally ordered mesopores in the plane, overcoming the mechanical robustness and ionic conductivity trade-off. Experimental results and simulations reveal that the -OH and -NH groups on the surface of artificial ion channels can promote rapid desolvation kinetics and serve as an ion sieve to homogenize the Zn2+ flux, thus inhibiting side reactions and ensuring uniform Zn deposition without dendrites. The 2D-mPDA@Zn electrode achieves an ultralow nucleation potential of 35 mV and maintains a Coulombic efficiency of 99.8% over 1500 cycles at 5 mA cm-2. Moreover, the symmetric battery exhibits a prolonged lifespan of over 580 h at a high current density of 20 mA cm-2. This biomimetic superstructured interphase also demonstrates the high feasibility in Zn//VO2 full cells and paves a new route for rechargeable aqueous metal-ion batteries.

Multifunctional Hierarchical Nanoplatform with Anisotropic Bimodal Mesopores for Effective Neural Circuit Reconstruction after Spinal Cord Injury.

A persistent inflammatory response, intrinsic limitations in axonal regenerative capacity, and widespread presence of extrinsic axonal inhibitors impede the restoration of motor function after a spinal cord injury (SCI). A versatile treatment platform is urgently needed to address diverse clinical manifestations of SCI. Herein, we present a multifunctional nanoplatform with anisotropic bimodal mesopores for effective neural circuit reconstruction after SCI. The hierarchical nanoplatform features of a Janus structure consist of dual compartments of hydrophilic mesoporous silica (mSiO2) and hydrophobic periodic mesoporous organosilica (PMO), each possessing distinct pore sizes of 12 and 3 nm, respectively. Unlike traditional hierarchical mesoporous nanomaterials with dual-mesopores interlaced with each other, the two sets of mesopores in this Janus nanoplatform are spatially independent and possess completely distinct chemical properties. The Janus mesopores facilitate controllable codelivery of dual drugs with distinct properties: the hydrophilic macromolecular enoxaparin (ENO) and the hydrophobic small molecular paclitaxel (PTX). Anchoring with CeO2, the resulting mSiO2&PMO-CeO2-PTX&ENO nanoformulation not only effectively alleviates ROS-induced neuronal apoptosis but also enhances microtubule stability to promote intrinsic axonal regeneration and facilitates axonal extension by diminishing the inhibitory effect of extracellular chondroitin sulfate proteoglycans. We believe that this functional dual-mesoporous nanoplatform holds significant potential for combination therapy in treating severe multifaceted diseases.

Black Titania Janus Mesoporous Nanomotor for Enhanced Tumor Penetration and Near-Infrared Light-Triggered Photodynamic Therapy.

Thanks to their excellent photoelectric characteristics to generate cytotoxic reactive oxygen species (ROS) under the light-activation process, TiO2 nanomaterials have shown significant potential in photodynamic therapy (PDT) for solid tumors. Nevertheless, the limited penetration depth of TiO2-based photosensitizers and excitation sources (UV/visible light) for PDT remains a formidable challenge when confronted with complex tumor microenvironments (TMEs). Here, we present a H2O2-driven black TiO2 mesoporous nanomotor with near-infrared (NIR) light absorption capability and autonomous navigation ability, which effectively enhances solid tumor penetration in NIR light-triggered PDT. The nanomotor was rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of a NIR light-responsive black TiO2 nanosphere and an enzyme-modified periodic mesoporous organosilica (PMO) nanorod that wraps around the TiO2 nanosphere. The overexpressed H2O2 can drive the nanomotor in the TME under catalysis of catalase in the PMO domain. By precisely controlling the ratio of TiO2 and PMO compartments in the Janus nanostructure, TiO2&PMO nanomotors can achieve optimal self-propulsive directionality and velocity, enhancing cellular uptake and facilitating deep tumor penetration. Additionally, by the decomposition of endogenous H2O2 within solid tumors, these nanomotors can continuously supply oxygen to enable highly efficient ROS production under the NIR photocatalysis of black TiO2, leading to intensified PDT effects and effective tumor inhibition.

Implanting Colloidal Nanoparticles into Single-Crystalline Zeolites for Catalytic Dehydration.

The encapsulation of functional colloidal nanoparticles (100 nm) into single-crystalline ZSM-5 zeolites, aiming to create uniform core-shell structures, is a highly sought-after yet formidable objective due to significant lattice mismatch and distinct crystallization properties. In this study, we demonstrate the fabrication of a core-shell structured single-crystal zeolite encompassing an Fe3O4 colloidal core via a novel confinement stepwise crystallization methodology. By engineering a confined nanocavity, anchoring nucleation sites, and executing stepwise crystallization, we have successfully encapsulated colloidal nanoparticles (CN) within single-crystal zeolites. These grafted sites, alongside the controlled crystallization process, compel the zeolite seed to nucleate and expand along the Fe3O4 colloidal nanoparticle surface, within a meticulously defined volume (1.5×107≤V≤1.3×108 nm3). Our strategy exhibits versatility and adaptability to an array of zeolites, including but not restricted to ZSM-5, NaA, ZSM-11, and TS-1 with polycrystalline zeolite shell. We highlight the uniformly structured magnetic-nucleus single-crystalline zeolite, which displays pronounced superparamagnetism (14 emu/g) and robust acidity (~0.83 mmol/g). This innovative material has been effectively utilized in a magnetically stabilized bed (MSB) reactor for the dehydration of ethanol, delivering an exceptional conversion rate (98 %), supreme ethylene selectivity (98 %), and superior catalytic endurance (in excess of 100 hours).

Micelles Cascade Assembly to Tandem Porous Catalyst for Waste Plastics Upcycling.

Catalytic upcycling of polyolefins into high-value chemicals represents the direction in end-of-life plastics valorization, but poses great challenges. Here, we report the synthesis of a tandem porous catalyst via a micelle cascade assembly strategy for selectively catalytic cracking of polyethylene into olefins at a low temperature. A hierarchically porous silica layer from mesopore to macropore is constructed on the surface of microporous ZSM-5 nanosheets through cascade assembly of dynamic micelles. The outer macropore arrays can adsorb bulky polyolefins quickly by the capillary and hydrophobic effects, enhancing the diffusion and access to active sites. The middle mesopores present a nanoconfinement space, pre-cracking polyolefins into intermediates by weak acid sites, which then transport into zeolites micropores for further cracking by strong Brønsted acid sites. The hierarchically porous and acidic structures, mimicking biomimetic protease catalytic clefts, ideally match the tandem cracking steps of polyolefins, thus suppressing coke formation and facilitating product escape. As a result, light hydrocarbons (C1-C7) are produced with a yield of 443 mmol gZSM-5 -1, where 74.3 % of them are C3-C6 olefins, much superior to ZSM-5 and porous silica catalysts. This tandem porous catalyst exemplifies a superstructure design of catalytic cracking catalysts for industrial and economical upcycling of plastic wastes.

Physical-Chemical Coupling Coassembly Approach to Branched Magnetic Mesoporous Nanochains with Adjustable Surface Roughness.

Self-assembly processes triggered by physical or chemical driving forces have been applied to fabricate hierarchical materials with subtle nanostructures. However, various physicochemical processes often interfere with each other, and their precise control has remained a great challenge. Here, in this paper, a rational synthesis of 1D magnetite-chain and mesoporous-silica-nanorod (Fe3O4&mSiO2) branched magnetic nanochains via a physical-chemical coupling coassembly approach is reported. Magnetic-field-induced assembly of magnetite Fe3O4 nanoparticles and isotropic/anisotropic assembly of mesoporous silica are coupled to obtain the delicate 1D branched magnetic mesoporous nanochains. The nanochains with a length of 2-3 µm in length are composed of aligned Fe3O4@mSiO2 nanospheres with a diameter of 150 nm and sticked-out 300 nm long mSiO2 branches. By properly coordinating the multiple assembly processes, the density and length of mSiO2 branches can well be adjusted. Because of the unique rough surface and length in correspondence to bacteria, the designed 1D Fe3O4&mSiO2 branched magnetic nanochains show strong bacterial adhesion and pressuring ability, performing bacterial inhibition over 60% at a low concentration (15 µg mL-1). This cooperative coassembly strategy deepens the understanding of the micro-nanoscale assembly process and lays a foundation for the preparation of the assembly with adjustable surface structures and the subsequent construction of complex multilevel structures.

Ultrasmall Inorganic Mesoporous Nanoparticles: Preparation, Functionalization, and Application.

Ultrasmall mesoporous nanoparticles (<50 nm), a unique porous nanomaterial, have been widely studied in many fields in the last decade owing to the abundant advantages, involving rich mesopores, low density, high surface area, numerous reaction sites, large cavity space, ultrasmall size, etc. This paper presents a review of recent advances in the preparation, functionalization, and applications of ultrasmall inorganic mesoporous nanoparticles for the first time. The soft monomicelles-directed method, in contrast to the hard-template and template-free methods, is more flexible in the synthesis of mesoporous nanoparticles. This is because the amphiphilic micelle has tunable functional blocks, controlled molecule masses, configurations and mesostructures. Focus on the soft micelle directing method, monomicelles could be classified into four types, i.e., the Pluronic-type block copolymer monomicelles, laboratory-synthesized amphiphilic block copolymers monomicelles, the single-molecule star-shaped block copolymer monomicelles, and the small-molecule anionic/cationic surfactant monomicelles. This paper also reviews the functionalization of the inner mesopores and the outer surfaces, which includes constructing the yolkshell structures (encapsulated nanoparticles), anchoring the active components packed on the shell and building an asymmetric Janus architecture. Then, several representative applications, involving catalysis, energy storage, and biomedicines are presented. Finally, the prospects and challenges of controlled synthesis and large-scale applications of ultrasmall mesoporous nanoparticles in the future are foreseen.

Three-Dimensionally Nanometallic Superstructure Synthesized via a Single-Particle Soft-Enveloping Strategy.

Three-dimensionally (3D) integrated metallic nanomaterials composed of two or more different types of nanostructures make up a class of advanced materials due to the multidimensional and synergistic effects between different components. However, designing and synthesizing intricate, well-defined metallic 3D nanomaterials remain great challenges. Here, a novel single-particle soft-enveloping strategy using a core-shell Au NP@mSiO2 particle as a template was proposed to synthesize 3D nanomaterials, namely, a Au nanoparticle@center-radial nanorod-Au-Pt nanoparticle (Au NP@NR-NP-Pt NP) superstructure. Taking advantage of the excellent plasmonic properties of Au NP@NR-NP by the synergistic plasmonic coupling of the outer Au NPs and inner Au nanorods, we can enhance the catalytic performance for 4-nitrophenol hydrogenation using Au NP@NR-NP-Pt NP as a photocatalyst with plasmon-excited hot electrons from Au NP@NR-NP under light irradiation, which is 2.76 times higher than in the dark. This process opens a door for the design of a new generation of 3D metallic nanomaterials for different fields.

Anomalous Detachment Behavior and Directional Reconstruction Regulation of Leaching-Type Precatalysts for Industrial Water Electrolyzers.

Current reconstruction chemistry studies are mainly operated at the laboratory scale, where the operating parameters are different from those used in industrial water electrolyzers. This gap leads to unclear reconstruction behaviors under industrial conditions and constrains the application of catalysts. Here, this work presents a new reconstruction mechanism and anomalous detachment phenomena observed in leaching-type oxygen-evolving precatalysts under industrial conditions, different from the reported results obtained under laboratory conditions. The identified detachment issues are closely linked to the production of a potassium salt separate phase, which proves sensitive to the local environment, and its instability easily leads to catalyst stripping from the substrate. By establishing detachment critical point and operating parameter-detachment correlation, a targeted reconstruction strategy is proposed to achieve smooth ligand leaching and effectively solve the detachment issue. Theoretical analyses validate the dual-site regulation in directionally reconstructed catalysts with optimized intermediate adsorption. Under industrial conditions, the coupled electrolyzer delivers an industrial-level current density at low cell voltage with prolonged durability, 1 A cm-2 at 2 V for over 340 h. This work bridges the gap of leaching-type precatalysts between laboratory test conditions and industrial operating conditions.

Electron-Donating Conjugation Effect Modulated Zn2+ Reduction Reaction for Separator-Free Aqueous Zinc Batteries.

Zinc-based aqueous batteries (ZABs) are attracting extensive attention due to the low cost, high capacity, and environmental benignity of the zinc anode. However, their application is still hindered by the undesired zinc dendrites. Despite Zn-surface modification being promising in relieving dendrites, a thick separator (i.e. glass fiber, 250-700 µm) is still required to resist the dendrite puncture, which limits volumetric energy density of battery. Here, we pivot from the traditional interphase plus extra separator categories, proposing an all-in-one ligand buffer layer (ca. 20 µm) to effectively modulate the Zn2+ transfer and deposition behaviors proved by in situ electrochemical digital holography. Experimental characterizations and density functional theory simulations further reveal that the catechol groups in the buffer layer can accelerate the Zn2+ reduction reaction (ZRR) through the electron-donating p-π conjugation effect, decreasing the negative charge in the coordination environment. Without extra separators, the elaborated system endows low polarization below 28.2 mV, long lifespan of 4950 h at 5 mA cm-2 in symmetric batteries, and an unprecedented volumetric energy density of 99.2 Wh L-1 based on the whole pouch cells. The concomitantly "separator-free" and "dendrite-free" conjugation effect with an accelerated ZRR process could foster the progression of metallic anodes and benefit energetic aqueous batteries.

Tandem Chemistry with Janus Mesopores Accelerator for Efficient Aqueous Batteries.

A reliable solid electrolyte interphase (SEI) on the metallic Zn anode is imperative for stable Zn-based aqueous batteries. However, the incompatible Zn-ion reduction processes, scilicet simultaneous adsorption (capture) and desolvation (repulsion) of Zn2+(H2O)6, raise kinetics and stability challenges for the design of SEI. Here, we demonstrate a tandem chemistry strategy to decouple and accelerate the concurrent adsorption and desolvation processes of the Zn2+ cluster at the inner Helmholtz layer. An electrochemically assembled perforative mesopore SiO2 interphase with tandem hydrophilic -OH and hydrophobic -F groups serves as a Janus mesopores accelerator to boost a fast and stable Zn2+ reduction reaction. Combining in situ electrochemical digital holography, molecular dynamics simulations, and spectroscopic characterizations reveals that -OH groups capture Zn2+ clusters from the bulk electrolyte and then -F groups repulse coordinated H2O molecules in the solvation shell to achieve the tandem ion reduction process. The resultant symmetric batteries exhibit reversible cycles over 8000 and 2000 h under high current densities of 4 and 10 mA cm-2, respectively. The feasibility of the tandem chemistry is further evidenced in both Zn//VO2 and Zn//I2 batteries, and it might be universal to other aqueous metal-ion batteries.

Ordered Mesoporous Crystalline Frameworks Toward Promising Energy Applications.

Ordered mesoporous crystalline frameworks (MCFs), which possess both functional frameworks and well-defined porosity, receive considerable attention because of their unique properties including high surface areas, large pore sizes, tailored porous structures, and compositions. Construction of novel crystalline mesoporous architectures that allows for rich accessible active sites and efficient mass transfer is envisaged to offer ample opportunities for potential energy-related applications. In this review, the rational synthesis, unique structures, and energy applications of MCFs are the main focus. After summarizing the synthetic approaches, an emphasis is placed on the delicate control of crystallites, mesophases, and nano-architectures by concluding basic principles and showing representative examples. Afterward, the currently fabricated components of MCFs such as metals, metal oxides, metal sulfides, and metal-organic frameworks are described in sequence. Further, typical applications of MCFs in rechargeable batteries, supercapacitors, electrocatalysis, and photocatalysis are highlighted. This review ends with the possible development and synthetic challenges of MCFs as well as a future prospect for high-efficiency energy applications, which underscores a pathway for developing advanced materials.

Spatially Asymmetric Nanoparticles for Boosting Ferroptosis in Tumor Therapy.

Despite its effectiveness in eliminating cancer cells, ferroptosis is hindered by the high natural antioxidant glutathione (GSH) levels in the tumor microenvironment. Herein, we developed a spatially asymmetric nanoparticle, Fe3O4@DMS&PDA@MnO2-SRF, for enhanced ferroptosis. It consists of two subunits: Fe3O4 nanoparticles coated with dendritic mesoporous silica (DMS) and PDA@MnO2 (PDA: polydopamine) loaded with sorafenib (SRF). The spatial isolation of the Fe3O4@DMS and PDA@MnO2-SRF subunits enhances the synergistic effect between the GSH-scavengers and ferroptosis-related components. First, the increased exposure of the Fe3O4 subunit enhances the Fenton reaction, leading to increased production of reactive oxygen species. Furthermore, the PDA@MnO2-SRF subunit effectively depletes GSH, thereby inducing ferroptosis by the inactivation of glutathione-dependent peroxidases 4. Moreover, the SRF blocks Xc- transport in tumor cells, augmenting GSH depletion capabilities. The dual GSH depletion of the Fe3O4@DMS&PDA@MnO2-SRF significantly weakens the antioxidative system, boosting the chemodynamic performance and leading to increased ferroptosis of tumor cells.

Boosted Oxygen Kinetics of Hierarchically Mesoporous Mo2C/C for High-current-density Zn-air Battery.

The high-current-density Zn-air battery shows big prospects in next-generation energy technologies, while sluggish O2 reaction and diffusion kinetics barricade the applications. Herein, the sequential assembly is innovatively demonstrated for hierarchically mesoporous molybdenum carbides/carbon microspheres with a tunable thickness of mesoporous carbon layers (Meso-Mo2C/C-x, where x represents the thickness). The optimum Meso-Mo2C/C-14 composites (≈2 µm in diameter) are composed of mesoporous nanosheets (≈38 nm in thickness), which possess bilateral mesoporous carbon layers (≈14 nm in thickness), inner Mo2C/C layers (≈8 nm in thickness) with orthorhombic Mo2C nanoparticles (≈2 nm in diameter), a high surface area of ≈426 m2 g-1, and open mesopores (≈6.9 nm in size). Experiments and calculations corroborate the hierarchically mesoporous Mo2C/C can enhance hydrophilicity for supplying sufficient O2, accelerate oxygen reduction kinetics by highly-active Mo2C and N-doped carbon sites, and facilitate O2 diffusion kinetics over hierarchically mesopores. Therefore, Meso-Mo2C/C-14 outputs a high half-wave potential (0.88 V vs RHE) with a low Tafel slope (51 mV dec-1) for oxygen reduction. More significantly, the Zn-air battery delivers an ultrahigh power density (272 mW cm-2), and an unprecedented 100 h stability at a high-current-density condition (100 mA cm-2), which is one of the best performances.

Mesoporous TiO2 Single-Crystal Particles from Controlled Crystallization-Driven Mono-Micelle Assembly as an Efficient Photocatalyst.

Mesoporous materials with crystalline frameworks have been widely explored in many fields due to their unique structure and crystalline feature, but accurate manipulations over crystalline scaffolds, mainly composed of uncontrolled polymorphs, are still lacking. Herein, we explored a controlled crystallization-driven monomicelle assembly approach to construct a type of uniform mesoporous TiO2 particles with atomically aligned single-crystal frameworks. The resultant mesoporous TiO2 single-crystal particles possess an angular shape ∼80 nm in diameter, good mesoporosity (a high surface area of 112 m2 g-1 and a mean pore size at 8.3 nm), and highly oriented anatase frameworks. By adjusting the evaporation rate during assembly, such a facile solution-processed strategy further enables the regulation of the particle size and mesopore size without the destruction of the oriented crystallites. Such a combination of ordered mesoporosity and crystalline orientation provides both effective mass and charge transportation, leading to a significant increase in the hydrogen generation rate. A maximum hydrogen evolution rate of 12.5 mmol g-1 h-1 can be realized, along with great stability under solar light. Our study is envisaged to extend the possibility of mesoporous single crystal growth to a range of functional ceramics and semiconductors toward advanced applications.