Unleash electron transfer in C-H functionalization by mesoporous carbon-supported palladium interstitial catalysts

Emerging Multiscale Porous Anodes toward Fast Charging Lithium-Ion Batteries

With the accelerated penetration of the global electric vehicle market, the demand for fast charging lithium-ion batteries (LIBs) that enable improvement of user driving efficiency and user experience is becoming increasingly significant. Robust ion/electron transport paths throughout the electrode have played a pivotal role in the progress of fast charging LIBs. Yet traditional graphite anodes lack fast ion transport channels, which suffer extremely elevated overpotential at ultrafast power outputs, resulting in lithium dendrite growth, capacity decay, and safety issues. In recent years, emergent multiscale porous anodes dedicated to building efficient ion transport channels on multiple scales offer opportunities for fast charging anodes. This review survey covers the recent advances of the emerging multiscale porous anodes for fast charging LIBs. It starts by clarifying how pore parameters such as porosity, tortuosity, and gradient affect the fast charging ability from an electrochemical kinetic perspective. We then present an overview of efforts to implement multiscale porous anodes at both material and electrode levels in diverse types of anode materials. Moreover, we critically evaluate the essential merits and limitations of several quintessential fast charging porous anodes from a practical viewpoint. Finally, we highlight the challenges and future prospects of multiscale porous fast charging anode design associated with materials and electrodes as well as crucial issues faced by the battery and management level.

Counting d-Orbital Vacancies of Transition-Metal Catalysts for the Sulfur Reduction Reaction

The electrocatalytic sulfur reduction reaction (SRR) would allow the production of renewable high-capacity rechargeable lithium-sulfur (Li-S) batteries using sustainable and nontoxic elemental sulfur as a cathode material, but its slow reaction rate causes a serious shuttle effect and dramatically reduces the capacity. We found that a catalyst composed of Pd nanoparticles supported by ordered mesoporous carbon (Pd/OMC) had a high reaction rate in the SRR, and a Li-S battery assembled with this catalyst had a low shuttle constant of 0.031 h-1 and a high-rate performance with a specific capacity of 1527 mAh g-1 at 0.1 C which is close to the theoretical value. The high activity of Pd/OMC with a d-orbital vacancy of 0.87 e was predicted from a volcano relationship between the d charge for the metal and the adsorption activation entropy and reaction rate for the SRR by examining Pd, Au, Pt, Rh, and Ru transition-metal nanocatalysts. The strategy of using a single electronic structure descriptor to design high-efficiency SRR catalysts has suggested a way to produce practical Li-S batteries.

Atomic Cu Sites Engineering Enables Efficient CO2 Electroreduction to Methane with High CH4/C2H4 Ratio

Electrochemical reduction of CO2 into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO2 capture and utilization, resulting from their high catalytic activity and selectivity. The mobility and accessibility of active sites in Cu-based catalysts significantly hinder the development of efficient Cu-based catalysts for CO2 electrochemical reduction reaction (CO2RR). Herein, a facile and effective strategy is developed to engineer accessible and structural stable Cu sites by incorporating single atomic Cu into the nitrogen cavities of the host graphitic carbon nitride (g-C3N4) as the active sites for CO2-to-CH4 conversion in CO2RR. By regulating the coordination and density of Cu sites in g-C3N4, an optimal catalyst corresponding to a one Cu atom in one nitrogen cavity reaches the highest CH4 Faraday efficiency of 49.04% and produces the products with a high CH4/C2H4 ratio over 9. This work provides the first experimental study on g-C3N4-supported single Cu atom catalyst for efficient CH4 production from CO2RR and suggests a principle in designing highly stable and selective high-efficiency Cu-based catalysts for CO2RR by engineering Cu active sites in 2D materials with porous crystal structures.

Moiré Superlattice Structure in Two-Dimensional Catalysts: Synthesis, Property and Activity

Two-dimensional (2D) layered materials have been widely used as catalysts due to their high specific surface area, large fraction of uncoordinated surface atoms, and high charge carrier mobility. Moiré superlattice emerges in 2D layered materials with twist angle or lattice mismatch. By manipulating the moiré superlattice structure, 2D layered materials present modulated electronic band structure, topological edge states, and unconventional superconductivity which are tightly associated with the performance of catalysts. Hence, engineering moiré superlattice structures are proposed to be an important technology in modifying 2D layered materials for improved catalytic properties. However, currently, the investigation of moiré superlattice structure in a catalytic application is still in its infancy. This perspective starts with the discussion of structural features and fabrication strategy of 2D materials with moiré superlattice structure. Afterward, the catalytic applications, including electrocatalytic and photocatalytic applications, are summarized. In particular, the promotion mechanism of the catalytic performance caused by the moiré superlattice structure is proposed. Finally, the perspective is concluded by outlining the remaining challenges and possible solutions for the future development of 2D materials with moiré superlattice structure towards the catalytic applications.

Iron Nanoparticles Protected by Chainmail-structured Graphene for Durable Electrocatalytic Nitrate Reduction to Nitrogen

The electrochemical nitrate reduction reaction (NO₃ RR) is an appealing technology for regulating the nitrogen cycle. Metallic iron is one of the well-known electrocatalysts for NO₃ RR, but it suffers from poor durability due to leaching and oxidation of iron during the electrocatalytic process. In this work, a graphene-nanochainmail-protected iron nanoparticle (Fe@Gnc) electrocatalyst is reported. It displays superior nitrate removal efficiency and high nitrogen selectivity. Notably, the catalyst delivers exceptional stability and durability, with the nitrate removal rate and nitrogen selectivity remained ≈96 % of that of the first time after up to 40 cycles (24 h for one cycle). As expected, the conductive graphene nanochainmail provides robust protection for the internal iron active sites, allowing Fe@Gnc to maintain its long-lasting electrochemical nitrate catalytic activity. This research proposes a workable solution for the scientific challenge of poor lasting ability of iron-based electrocatalysts in large-scale industrialization.

Palladium catalyzed radical relay for the oxidative cross-coupling of quinolines

Traditional approaches for transition-metal catalyzed oxidative cross-coupling reactions rely on sp²-hybridized starting materials, such as aryl halides, and more specifically, homogeneous catalysts. We report a heterogeneous Pd-catalyzed radical relay method for the conversion of a heteroarene C(sp³)–H bond into ethers. Pd nanoparticles are supported on an ordered mesoporous composite which, when compared with microporous activated carbons, greatly increases the Pd d charge because of their strong interaction with N-doped anatase nanocrystals. Mechanistic studies provide evidence that electron-deficient Pd with Pd–O/N coordinations efficiently catalyzes the radical relay reaction to release diffusible methoxyl radicals, and highlight the difference between this surface reaction and C–H oxidation mediated by homogeneous catalysts that operate with cyclopalladated intermediates. The reactions proceed efficiently with a turn-over frequency of 84 h⁻¹ and high selectivity toward ethers of >99%. Negligible Pd leaching and activity loss are observed after 7 catalytic runs.

Traditional approaches for transition-metal catalyzed oxidative cross-coupling reactions rely on sp²-hybridized starting materials. Here the authors report a heterogeneous Pd-catalyzed radical relay method for the conversion of a heteroarene C(sp³)–H bond into ethers.

ZIF-Derived Metal/N-Doped Porous Carbon Nanocomposites: Efficient Catalysts for Organic Transformations

Recently, zeolitic imidazolate framework (ZIF)-derived metal/N-doped porous carbon nanocomposites (M@NCs) have emerged as a class of appealing heterogeneous catalysts applied in organic synthesis, and the striking features mainly involve low-cost...