P-Bridging Asymmetry Diatomic Catalysts Sites Drive Efficient Bifunctional Oxygen Electrocatalysis for Zinc-Air Batteries.

Rechargeable zinc-air batteries (ZABs) rely on the development of high-performance bifunctional oxygen electrocatalysts to facilitate efficient oxygen reduction/evolution reactions (ORR/OER). Single-atom catalysts (SACs), characterized by their precisely defined active sites, have great potential for applications in ZABs. However, the design and architecture of atomic site electrocatalysts with both high activity and durability present significant challenges, owing to their spatial confinement and electronic states. In this study, a strategy is proposed to fabricate structurally uniform dual single-atom electrocatalyst (denoted as P-FeCo/NC) consisting of P-bridging Fe and Co bimetal atom (i.e., Fe-P-Co) decorated on N, P-co-doped carbon framework as an efficient and durable bifunctional electrocatalyst for ZABs. Experimental investigations and theoretical calculations reveal that the Fe-P-Co bridge-coupling structure enables a facile adsorption/desorption of oxygen intermediates and low activation barrier. The resultant P-FeCo/NC exhibits ultralow overpotential of 340 mV at 10 mA cm-2 for OER and high half-wave potential of 0.95 V for ORR. In addition, the application of P-FeCo/NC in rechargeable ZABs demonstrates enhanced performance with maximum power density of 115 mW cm-2 and long cyclic stability, which surpass Pt/C and RuO2 catalysts. This study provides valuable insights into the design and mechanism of atomically dispersed catalysts for energy conversion applications.

Cascade Anchoring Strategy for Fabricating High-Loading Pt Single Atoms as Bifunctional Catalysts for Electrocatalytic Hydrogen Evolution and Oxygen Reduction Reactions.

Carbon supports containing single-atomically dispersed metal-Nx (denoted as MSAC-NxCy, x, y: coordination number) have attracted increasing attention due to their superb performance in heterogeneous catalysis. However, large-scale controllable preparation of single-atom catalysts (SACs) with high concentration of supported metal-Nx is still a big challenge because of the metal atom agglomeration during synthesis at high density and temperatures. Herein, we report a stepwise anchoring strategy from a 1,10-o-phenanthroline Pt chelate to an Nx-doped carbon (NxCy) with isolated Pt single-atom catalysts (PtSAC-NxCy) containing Pt loadings up to 5.31 wt % measured via energy-dispersive X-ray spectroscopy (EDS). The results show that 1,10-o-phenanthroline Pt chelate predominantly contributes to the formation of chelate single metal sites that bind tightly to platinum ions to prevent metal atoms from aggregating, resulting in high metal loading. The high-loading PtSAC-NxCy exhibits a low hydrogen evolution (HER) overpotential of 24 mV at 0.010 A cm-2 current density with a relatively small Tafel gradient of 60.25 mV dec-1 and excellent stable performance. In addition, the PtSAC-NxCy catalyst shows excellent oxygen reduction reaction (ORR) catalytic activity with good stability, represented by the fast ORR kinetics under high-potential conditions. Theoretical calculations show that PtSAC-NC3 (x = 1, y = 3) offers a lower H2O activation energy barrier than Pt nanoparticles. The adsorption free energy of a H atom on a Pt single-atom site is lower than that on a Pt cluster, which is easier for H2 desorption. This study provides a potentially powerful cascade anchoring strategy in the design of other stable MSAC-NxCy catalysts with high-density metal-Nx sites for the HER and ORR.

High-Entropy Perovskites for Energy Conversion and Storage: Design, Synthesis, and Potential Applications.

Perovskites have shown tremendous promise as functional materials for several energy conversion and storage technologies, including rechargeable batteries, (electro)catalysts, fuel cells, and solar cells. Due to their excellent operational stability and performance, high-entropy perovskites (HEPs) have emerged as a new type of perovskite framework. Herein, this work reviews the recent progress in the development of HEPs, including synthesis methods and applications. Effective strategies for the design of HEPs through atomistic computations are also surveyed. Finally, an outlook of this field provides guidance for the development of new and improved HEPs.

Facile and Universal Defect Engineering Toward Highly Stable Carbon-Based Polymer Brushes with High Grafting Density.

Carbon-based polymer brushes (CBPBs) are an important class of functional polymer materials, which synergistically combine the advantageous properties of both carbons and polymers. However, the conventional fabrication procedures of CBPBs involve tedious multistep modification, including preoxidation of carbon substrates, introduction of initiating groups, and subsequent graft polymerization. In this study, a simple yet versatile defect-engineering strategy is proposed for the efficient synthesis of high-grafting-density CBPBs with highly stable CC linkages via free radical polymerization. This strategy involves the introduction and removal of nitrogen heteroatoms in the carbon skeletons via a simple temperature-Fmed heat treatment, leading to the formation of numerous carbon defects (e.g., pentagons, heptagons, and octagons) with reactive C=C bonds in the carbon substrates. The as-proposed methodology enables the facile fabrication of CBPBs with various carbon substrates and polymers. More importantly, the highly grafted polymer chains in the resulting CBPBs are tethered with the carbon skeletons by robust CC bonds, which can endure strong acid and alkali environments. These interesting findings will shed new light on the well-orchestrated design of CBPBs and broaden their applications in various areas with fascinating performances.

A versatile sea anemone-inspired strategy toward 2D hybrid porous carbons from functional molecular brushes.

A generalized and facile strategy toward 2D hybrid porous carbons (2DHPCs) with various highly active functional species (e.g. Co, B, and P) is developed via 2D molecular brushes as biomimetic building blocks. The resulting 2DHPCs present superior electrochemical energy conversion and storage properties.

Template-Free Preparation of Hierarchical Porous Carbon Nanosheets for Lithium-Sulfur Battery.

Porous carbon nanosheets have the advantages of longitudinal continuity, transverse ultrathin, high specific surface area, and surface atomic activity, as well as the synergistic effect of micro and nanoproperties, so the research on their preparation, structure, and properties has attracted wide attention. A series of ultrathin hierarchical porous carbon nanosheets (HPCNs) is fabricated through carbonization of precursors obtained through the Friedel-Crafts reaction-assisted loading of polystyrene on graphene oxide. Hierarchical pore structures consist of three parts: (1) the micropores (1.3 nm), which were provided by porous polystyrene through the Friedel-Crafts reaction; (2) the mesopores (3.8 nm), which were provided by slab pores from the stack of carbon nanosheets; and (3) the pores (>5 nm) formed from the random stack of carbon nanosheets. Controlling the carbonization time and temperature adds to a prominent increase in specific surface area from 405.8 to 1420 m2 g-1. It was found that excessive carbonization would destroy the hierarchical pore structure. These porous carbon materials were used as cathode materials for lithium-sulfur battery and showed good performance. HPCN/sulfur cathode has good rate performance and cycle performance, and the capacity retention rate is 87% after the current density rises from 1 to 3 C and 91% after 200 cycles.

A versatile bottom-up interface self-assembly strategy to hairy nanoparticle-based 2D monolayered composite and functional nanosheets.

Herein, we present a universal bottom-up interface self-assembly of hairy nanoparticle strategy for 2D monolayered composite and functional nanosheets, including polymeric composite nanosheets and functional porous polymer and carbon nanosheets. By using diverse hairy nanoparticles as building blocks, a series of 2D monolayered polymeric composite nanosheets was prepared, demonstrating the universality of our strategy. Furthermore, the 2D polymeric composites could be easily transformed into 2D monolayered functional porous polymer and carbon nanosheets. We hope that this strategy will open a new door for the design and fabrication of advanced 2D composite and functional nanosheets and thus provide new opportunities for different fields including the environment, energy, catalysis and medicine.

Fabrication of Porous Nanonetwork-Structured Carbons from Well-Defined Cylindrical Molecular Bottlebrushes.

Atom transfer radical polymerization was utilized to prepare well-defined cylindrical molecular bottlebrushes which were employed as building blocks and transformed into porous nanonetwork-structured carbons (PNSCs) via hypercross-linking chemistry and shape-regulated carbonization. The as-prepared PNSCs exhibited a unique nanomorphology-tunable characteristic by simply varying carbonization conditions. Because of their three-dimensional network nanomorphologies with well-developed hierarchical porous structures and conductive carbon framework, the PNSCs demonstrated excellent electrochemical performance in lithium-sulfur batteries.

Construction of functional nanonetwork-structured carbon nitride with Au nanoparticle yolks for highly efficient photocatalytic applications.

We report a novel and versatile fabrication strategy for functional nanonetwork-structured carbon nitride with Au nanoparticle yolks (FNNS-C3N4-Au) based on hairy poly(acrylic acid)-grafted SiO2 nanospheres (Au@SiO2-g-PAA). Benefiting from the three-dimensional nanonetwork structure and well-distributed Au nanoparticles, the as-prepared nanocomposites demonstrated excellent photocatalysis performances (degradation rate constant: 1.8 × 10-2 min-1).

Lightweight, Highly Permeable, Biocompatible, and Antiadhesive Composite Meshes for Intraperitoneal Repairs.

Ventral hernia is a public health issue and millions of meshes are used to repair abdominal wall defects every year. Polypropylene-based composite meshes represent an important class of materials for intraperitoneal repair, but the meshes generally give rise to infection, seroma, migration, and adhesion, leading to severe consequence or even reoperation. Here, a facile and versatile one-way fabrication of lightweight, highly permeable, and biocompatible composite meshes with superior antiadhesion properties is proposed by modifying polypropylene meshes with well-defined polydopamine nanocoating. The resulting composite meshes are found to significantly enhance the biocompatibility and antiadhesion effect in rat model. The scalable production and excellent biomedical properties of composite meshes make them a promising candidate for future-generation ventral hernia repair materials.

Superhierarchical Cobalt-Embedded Nitrogen-Doped Porous Carbon Nanosheets as Two-in-One Hosts for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries, based on the redox reaction between elemental sulfur and lithium metal, have attracted great interest because of their inherently high theoretical energy density. However, the severe polysulfide shuttle effect and sluggish reaction kinetics in sulfur cathodes, as well as dendrite growth in lithium-metal anodes are great obstacles for their practical application. Herein, a two-in-one approach with superhierarchical cobalt-embedded nitrogen-doped porous carbon nanosheets (Co/N-PCNSs) as stable hosts for both elemental sulfur and metallic lithium to improve their performance simultaneously is reported. Experimental and theoretical results reveal that stable Co nanoparticles, elaborately encapsulated by N-doped graphitic carbon, can work synergistically with N heteroatoms to reserve the soluble polysulfides and promote the redox reaction kinetics of sulfur cathodes. Moreover, the high-surface-area pore structure and the Co-enhanced lithiophilic N heteroatoms in Co/N-PCNSs can regulate metallic lithium plating and successfully suppress lithium dendrite growth in the anodes. As a result, a full lithium-sulfur cell constructed with Co/N-PCNSs as two-in-one hosts demonstrates excellent capacity retention with stable Coulombic efficiency.

A simple self-assembly strategy for ultrahigh surface area nitrogen-doped porous carbon nanospheres with enhanced adsorption and energy storage performances.

A class of novel N-doped porous carbon nanospheres (PCNSs) with ultrahigh surface areas (e.g., Langmuir surface area = 3219 m2 g-1) and large templated mesopore diameters (up to 18.6 nm) was synthesized based upon a simple yet efficient copolymerization-induced self-assembly process of aniline/pyrrole co-monomers and block copolymer templates. The PCNSs exhibited enhanced adsorption properties towards creatinine and superior lithium-sulfur battery performances.

Silica nanonetwork confined in nitrogen-doped ordered mesoporous carbon framework for high-performance lithium-ion battery anodes.

A new class of nitrogen-doped ordered mesoporous carbon/silica (N-OMC/SiO2) nanocomposites was successfully fabricated via a multi-constituent co-assembly strategy. The N-OMC/SiO2 nanocomposite presented a unique interpenetrating carbon/silica structure whose carbon/silica interface is highly uniform, and thus demonstrated high capacity, good cycling and excellent rate properties.