EnergyChem最新文献

The ever-growing market for electric vehicles and grid-scale energy storage is boosting the development of high energy density lithium metal batteries (LMBs). Solid-state electrolytes (SSEs) are not only nonflammable to overcome the intrinsic drawbacks of liquid electrolytes, but also mechanically strong enough to suppress the growth of lithium dendrites, whose development could greatly promote the safety and performance of LMBs. Crystalline porous materials (CPMs) with high surface area, adjustable pores, ordered channels, and versatile functionality have not only provided a promising structural platform for designing fast ionic conducting materials, but also offered great opportunities for manipulating their physicochemical and electrochemical properties, which have shown great potential to fabricate high-performance SSEs and have become an emerging research direction in recent years. In this review, the latest progress of CPMs-based SSEs for LMBs, including pristine CPMs and CPMs-based composites, is systematically summarized. By discussing the pioneer work, both merits and issues arising from CPMs are emphasized as well as an outlook for the development of CPMs-based SSEs with high-performance and reliable safety are presented.

Benefiting from high thermal storage density, wide temperature regulation range, operational simplicity, and economic feasibility, latent heat-based thermal energy storage (TES) is comparatively accepted as a cutting-edge TES concept, especially solid-liquid phase change materials (PCMs). However, liquid phase leakage, low thermal/electrical conductivities, weak photoabsorption capacity, and intrinsic rigidity of pristine PCMs are long-standing bottlenecks in both industrial and domestic application scenarios. Towards these goals, emerging two-dimensional (2D) materials containing regions of empty nanospace are ideal alternatives to efficiently encapsulate PCMs molecules and rationalize physical phase transformation, especially graphene, MXene and BN. Herein, we provide a timely and comprehensive review highlighting versatile roles of 2D materials in composite PCMs and relationships between their architectures and thermophysical properties. In addition, we provide an in-depth understanding of the energy conversion mechanisms and rationalize routes to high-efficiency energy conversion PCMs. Finally, we also introduced critical considerations on the challenges and opportunities in the development of advanced high-performance and multifunctional 2D material-based composite PCMs, hoping to provide constructive references and facilitate their significant breakthroughs in both fundamental researches and commercial applications.

Water electrolysis has aroused extensive research efforts due to its potential applications of sewage disposal, microorganism treatment and direct electrolysis for large-scale hydrogen production. At this background, transition metal nitrides (TMNs) have raised lots of attention, because their physical properties are similar to those of metallic elements and TMNs have unique electron orbital structures. The inner nitrogens can increase the electron density of d-bands of transition metals, so that the electronic structures of TMNs are similar with some precious metals, whose density of states can cross the Fermi level. Therefore, TMNs have similar conductivities with metals and possess superior electrocatalytic performance. Nanostructured TMNs tend to have relatively large dispersion and more exposed active sites, which have direct improvement for catalytic activity and stability as electrochemical catalysts. This review summarizes the representative progress of TMNs based catalysts on both synthetic strategies of structural engineering and electronic engineering for improving electrocatalytic performance, especially in hydrogen evolution, oxygen evolution and water splitting. Finally, we further propose the future challenges and research directions of nanostructured TMNs in the electrochemical energy fields of efficient preparations and performance enhancements.

Dealloying, which is traditionally originated in the research of alloy corrosion, has recently been developed as a robust and generic method for fabricating functional 3D nanoporous materials. Endorsed by the unique 3D bicontinuous porous structure, they exhibit remarkable properties such as large surface area, high conductivity, efficient mass transport, and high catalytic activity, which render them as advanced nanomaterials with enormous potential for a variety of applications. In this review, we summarize recent progress in the development of dealloying and dealloyed nanoporous materials for electrochemical energy conversion and storage. Beginning with an overview of the modern understanding of dealloying mechanisms, the unique structural and physical properties of dealloyed nanoporous materials are introduced. Then, we discuss the established dealloying techniques and how they enable the versatile fabrication of a diverse variety of nanoporous materials, ranging from unary metals and alloys to the latest high-entropy alloys and two-dimensional materials. Following that, the electrochemical applications of dealloyed nanoporous materials for fuel cells, supercapacitors, metal-ion batteries, alkali metal batteries, non-aqueous metal-oxygen batteries, electrochemical CO₂ reduction, and electrocatalytic N₂ reduction are highlighted. Finally, we discuss remaining challenges in this field and offer perspectives on potential directions for future research.

Plasmonic nanostructures have provided unique opportunities for harvesting solar energy to facilitate various chemical reactions. In the past decade, localized surface plasmon resonance (LSPR) has been extensively explored in catalysis to increase the activity and selectivity of chemical transformation reactions under mild reaction conditions, however, they are still subjected to many challenges in terms of lower efficiency, stability and reaction mechanisms under light irradiation conditions. There have been numerous research efforts in exploring the catalytic trends, mechanisms, challenges and applications in plasmonic catalysis. Several cutting-edge characterization techniques (UV-vis, surface voltage spectroscopy, SERS, photoluminescence, photocurrent measurements and theoretical simulations) have been employed to characterize and establish the structure-property relationship of noble metal-based plasmonic hybrid nanostructures. In this review, we have attempted to correlate the operando techniques to understand the structural details and their plasmonic catalytic activities in emerging applications, hydrogen generation and CO₂ reduction reactions.

The development of clean and sustainable energy is crucial to solve the increasingly serious energy crisis. Metal-organic frameworks (MOFs) containing both inorganic and organic components have attracted extensive attention on energy applications because of their tunable structures and fascinating properties. Particularly, liquid-phase epitaxial (LPE) layer by layer (LBL) growth of MOFs thin films on various substrates surfaces (called SURMOFs, surface-coordinated MOF thin films) possess the advantages of controlled thickness, preferred growth orientation and homogeneous film, which provide ideal candidates for energy storage and conversion. In this review, we summarize the fabrication strategies of SURMOFs including the layer by layer dipping, pump, spray, spin-coating and flowing methods, the classification and advantages of SURMOFs, and then discuss the related energy applications of SURMOFs, encapsulated SURMOFs, and SURMOF-derivative on electrocatalysis, photocatalysis, and solar cells etc.

Most processes in energy chemistry require suitable catalysts to decrease activation energy, control reaction rate and increase selectivity. As a kind of very important supports, nanocarbons are widely used for constructing various metal-based heterogenous catalysts owing to their abundant microstructures and morphologies, tunable surface area, high stability, low cost and excellent electrical conductivity. Nitrogen-doped nanocarbons are the even more attractive for the modified electronic structure and enhanced interaction with the supported species. With the assistance of N participation, metal catalysts have been constructed on N-doped nanocarbons from highly dispersed nanoparticles to sub-nanometer clusters and single sites. The metal catalysts supported on N-doped nanocarbons have exhibited unique advantages of modified electronic structure, facilitated charge transfer and high metal utilization, hence show wide applications in various energy-related reactions. This review firstly elucidates the roles of different types of nitrogen dopants for anchoring metal species from theoretical viewpoint, then summarizes the synthetic strategies of various N-doped nanocarbons and the related metal catalysts from high dispersion to single sites. Then their typical performances in energy chemistry are reviewed which ranges from electrocatalytic applications including oxygen reduction, alcohol oxidation, hydrogen oxidation, water splitting, CO₂ reduction and nitrogen reduction to thermal catalytic reactions including Fischer-Tropsch synthesis, H₂ production, hydrogenation and oxidation, as well as to photocatalytic applications and beyond. The structure-performance correlations are discussed in depth to highlight the contribution of N-doped nanocarbons. The facing challenges and research trends are also discussed for better understanding the development of advanced heterogeneous catalysts based on the heteroatom-doped nanocarbons for energy applications.

Reticular frameworks including metal−organic frameworks (MOFs) and covalent organic frameworks (COFs), and their derived materials have drawn global attention in the capture and conversion of CO₂ as a cheap feedstock into fine chemicals and fuels due to their facile synthesis and programmable highly porous structures. This review comprehensively summarizes the progress in thermo−catalysis of CO₂ conversion by reticular framework−based catalysts to afford chemicals such as cyclic carbonates, cyclic carbamates, formamides, carboxylic acid, carbon monoxide, formate, methanol, methane, and light olefins. Firstly, the characteristics and advantages of MOF−based materials for CO₂ conversion are introduced. Secondly, the characteristics and advantages of COF−based materials for CO₂ conversion are presented. Subsequently, the CO₂ conversion reactions are briefly classified and discussed. Particularly, MOF or COF−based catalysts for each reaction are summarized in terms of catalyst design, catalytic performance and catalytic mechanism. Finally, the perspectives for further development of reticular framework−based catalysts for efficient CO₂ conversion are discussed. We hope this review can provide an inspiration for the rational design of porous crystalline materials for thermal catalytic CO₂ conversion.

Since the late 1990s, much progress has been made in the field of the chemistry of flexible porous coordination polymers (PCPs). Various PCP architectures have been recognized and several promising applications have been identified, e.g., in the areas of selective gas capture and separation, sensors, and drug carriers. The crystalline and flexible frameworks of PCPs can respond to various external stimuli and then adjust themselves to adapt to new environments in a tuneable fashionࣧ behavior that is seldom observed in other porous solids. Over the past decade, following on from developments made in terms of flexible PCP performance, how to accurately build these architectures with the required functions has become a new challenge. In this review, the authors focus on the three aspects of flexible PCPs: 1) classifying the flexible systems with different fashions of pore opening, 2) classifying the flexible PCPs with governing factors of internal structure and external conditions, and 3) introducing, and summarizing, flexibility- and structure-dependent performance. The goal is to present the state-of-art chemistry and application of flexible PCPs and to offer an outlook towards discovering and designing further new materials.

The performance degradation of proton exchange membrane fuel cells (PEMFCs) is one of the most critical challenges in their practical applications. Degradations of electrocatalysts for oxygen reduction reaction (ORR) at cathode and hydrogen oxidation reaction (HOR) at the anode are the major contributors to PEMFC degradation, which are mainly induced by fuel/air impurities, unintentional harmful species during the preparation and use of the catalysts, as well as catalyst decomposition during the operation. This review summarizes the recent research on PEMFC performance degradation and the progress in developing mitigation strategies for avoiding the degradation. Several aspects are emphasized as follows: the understanding of catalyst poisoning phenomena, influencing factors, and general degradation mechanisms. Several technical challenges are analyzed and the corresponding future research directions are proposed to facilitate the further research and development of mitigation strategies for PEMFC catalyst degradation.