EnergyChem最新文献

Rechargeable Li/Na/Zn metal batteries are promising next-generation energy-storage systems owing to their high energy density. However, the inhomogeneous deposition behavior, severe dendrite growth and drastic volume variation hinder the practical applications of Li/Na/Zn metal anodes. Three-dimensional (3D) carbon-based substrates have received extensive attention in view of their low cost, high electronic conductivity, and adjustable physicochemical characteristic. Moreover, their interconnected network architecture can accommodate the enormous internal stress fluctuation, homogenize electric field distribution, and mitigate Li/Na/Zn dendrite growth. Herein, we review the recent advances in 3D carbon-based hosts employing surface modification strategies to accomplish spatially confined deposition behavior of metallic Li/Na/Zn. Firstly, self-templated synthesis and hard-templating synthesis for manufacturing the 3D carbon-based scaffolds are briefly presented. Subsequently, we investigate several typical surface modification strategies, including heteroatom doping, surface functionalization, decoration of nucleation sites, and skeleton gradient design of metallophilicity and electronic conductivity. Finally, the future perspectives on several research orientations for the commercial application of 3D carbon-based hosts as metal anodes are emphasized.

In the past decades, metal-organic frameworks (MOFs) have gained great attention as a promising candidate in photocatalytic applications, leveraging their tunable pores, well-defined structures, ease of functionalization and inherent semiconductor properties. Nevertheless, owing to their poor light-harvesting capability and suboptimal electron-hole separation efficiency, their catalytic performances have yet to meet the prerequisites for industrial deployment. To address this issue, researchers started to incorporate guest substances into MOFs, thereby integrating multiple functions or advantages to form MOF composites. Through the construction of active interfaces and the introduction of functional units, the light absorption capacity, charge separation and the reaction activity are pointedly optimized, thus enhancing the overall photocatalytic performances. Moreover, the composites exhibit various active sites with well-defined coordination configuration, facilitating the study of the photocatalytic mechanism. Herein, this review provides an overview of commonly used MOF composites in photocatalysis, including metal nanoparticles/MOFs, semiconductors/MOFs, carbon materials/MOFs, aerogels/MOFs, polymers/MOFs, reticular frameworks/MOFs, and MOF composites with others, summarizes their synthesis strategies, and presents their latest applications in photocatalytic water splitting, CO₂ reduction, N₂ reduction and organic reactions. We hope that this review will highlight the advantages and challenges of MOF composites in photocatalysis and inspire the development of more efficient and widely applicable novel MOF composite photocatalysts.

Photocatalytic solar-to-chemical energy conversion is deemed to be a promising, eco-friendly, and low-energy input strategy for addressing the energy crisis. Donor−acceptor (D−A) conjugated polymers (CPs) have recently emerged as the hub in photocatalysis due to their charming properties, such as variable molecular structure, accessible functionalization, tunable electronic band structure, and versatile synthetic approaches. These features enable D−A-based CPs to be a potential alternative for conventional inorganic photocatalysts. Currently, researchers are making great efforts to design highly-efficient D−A-based CPs for adaptable photocatalytic reactions. In this review, the development, classification, and common synthetic strategies of D−A-based CPs are introduced. The recent progress of D−A-based CPs in photocatalytic energy conversion is systematically summarized, including photocatalytic H₂ evolution, O₂ evolution, overall water splitting, CO₂ reduction, H₂O₂ production, and organic transformation. Meanwhile, the impacts of molecular/electronic structure and morphology of D−A-based CPs on light-harvesting capacity, exciton dissociation, and interfacial reaction during the photo-redox reactions are clarified. Finally, the conclusions and future challenges for photocatalytic energy conversion over D−A-based CPs are provided. This review is expected to offer an in-depth and comprehensive understanding of photocatalytic energy conversion in the aspect of mechanism, as well as to stimulate inspiration for designing D−A-based CP photocatalysts with surpassing efficiency.

Two-dimensional (2D) transition metal carbides and/or nitrides, known as MXenes, are promising building blocks in energy storage devices and other applications. In particular, the 2D morphology, high aspect ratio coupled with the metallic conductivity and distinguished Youngs modulus open up intriguing opportunities for MXenes to assemble electrodes, decorate electrolyte or separator with enhanced stability and performances. Understanding the correlations between these physical properties of MXenes and the required functions in supercapacitor and batteries are of great importance. In this review, we discuss the critical roles of MXene components in the electrode architecture, particularly through the viewpoints of conductive electrode host and mechanically additive binders to enhance the electron transfer and structural stability. MXenes as mechanical reinforcement phases in electrolyte and separator materials are also highlighted. Finally, we conclude the challenges and future perspectives of MXenes in advanced energy storage applications.

Elevated-temperature adsorptive separation involves the selective and rapid adsorption of gas molecules on weakly bonding chemical sites of an adsorbent at elevated temperatures (80–500 °C) and the reversible desorption of the gas molecules at a low cost. It is a significant step in several reactions, such as pre-combustion carbon capture, indirect/direct hydrogen production, ammonia separation, oxygen production from air, and carbon monoxide enrichment. This purification strategy avoids sensible heat loss of the feed gas, heat regeneration, accelerates adsorption kinetics, and can sometimes couple catalysts to achieve sorption-enhanced reactions. Before commercializing elevated-temperature adsorptive separation technologies, highly efficient syntheses for obtaining elevated-temperature-responsive adsorbents are required; competitive adsorption, interactions with gas impurities, and poisoning mechanisms need to be well understood; specific adsorption reactors and processes should also be designed. Therefore, this review covers the key progress made in terms of material design and synthesis, adsorption kinetic models and mechanisms, process design and optimization, as well as system integration for elevated-temperature adsorptive separation. This review will be valuable for the clean fossil-fuel utilization community, as well as energy and chemical industries.

Energy catalysis and storage are the key technologies to solve energy and environmental problems in energy systems. Two-dimensional (2D) boron nitride nanomaterials have aroused a great interest in the synthesis and application because of their unique 2D nature, large band gap, metal-free characteristic, high thermal/mechanical stability, and easy accessibility. The composition and coordination determine the geometric and electronic structures of boron nitride nanosheet and greatly influence the catalytic performance in numerous important reactions. The reviews with close relation on the aspect the comprehensive analysis of boron nitride nanosheet used for energy conversion and storage have expansive research space in the field of catalysis. Herein, this review narrates the physicochemical properties of boron nitride nanomaterials and summarizes the synthetic strategies of various boron nitride nanosheets in detail. Keystone is concentrated on the rational design, applied actuality and developing prospect of boron nitride nanomaterials. The abundant applications in energy catalysis and storage including electrocatalysis, photocatalysis, catalytic de/re-hydrogenation, chemo-catalytic hydrogen generation, rechargeable battery and supercapacitors were investigated. Furthermore, corresponding practical application are also studied in this review. Illustratively, the structure characterization, mechanism insights, the current challenges and potential applications of boron nitride-based materials for energy catalysis and storage are minutely discussed.

Electrochemical carbon dioxide reduction (CO₂RR) to chemicals and fuels is a promising way to alleviate global environmental problems and energy issues. Among the various catalysts, metal-nitrogen-carbon (M–N–C) single-atom catalysts (SACs) have intrigued great excitement in catalysis due to their low cost and high efficiency. However, precisely identifying the active site structure at an atomic level and disclosing the structure-performance relationship remains a grand challenge. In this review, the active structures of the M–N–C catalysts in CO₂RR are first summarized, including isolated metal-N_x (x = 2, 3, 4, 5) sites, dual-metal centers, and the crucial role of substrates. Subsequently, the role of active structure in changing the adsorption properties of reactants toward CO₂RR is discussed. In particular, the structure-performance relationship and constructive strategies to optimize the CO₂RR pathway are highlighted. Finally, challenges and potential outlooks for the development of M–N–C SACs toward CO₂RR are presented.

Inspired by enzymatic catalysis, a variety of covalent organic frameworks (COFs), which have precisely engineered microenvironments enabled by the well-defined porous channels and cavities with catalytically active sites built in, have been developed to mimic the catalytic process of enzymes. The structure diversity and customizability of COFs make them an ideal platform for studying the catalyst structure-activity relationship in heterogeneous catalysis and obtaining a thorough understanding of the catalytic mechanisms. In this review, we summarize the recent progress in the development of COF materials for catalysis applications, with a particular focus on their microenvironment effects. Representative examples of organocatalysis, asymmetric organocatalysis, and metal-supported catalysis utilizing the microenvironment effect enabled by diversified COF materials are discussed. Finally, we outline the key fundamental issues to be addressed and provide our perspectives on the future of COF-based catalysis.

CO₂ electrolysis technology powered by renewable electricity is a sustainable strategy to reduce anthropogenic carbon emissions while producing valuable chemicals. Unfortunately, compared with CO₂ reduction reaction (CO₂RR) in cathode, the sluggish-kinetics and low value-added product (i.e., O₂) of anodic oxygen evolution reaction (OER) during CO₂ electrolysis will seriously drag down the whole efficiency and economic benefits. Alternatively, replacing OER with some thermodynamically more favorable oxidation reactions is promising to reduce energy input while producing high value-added products. Therefore, coupling CO₂RR with these oxidation reactions to construct paired electrosynthesis systems is more meaningful for future applications, which has gained some far-reaching achievements in recent years. In this review, we summarize recent progress in construction of paired electrosynthesis systems involving CO₂RR and propose possible future research directions. We start with fundamentals about traditional CO₂ electrolysis. Then we propose the definition and classification of paired electrolysis, especially those involving CO₂RR. Subsequently, we emphatically discuss the selection of various oxidation reactions coupled with CO₂RR in the proposed paired electrolysis systems. Finally, from our point of view, the current challenges and corresponding perspectives on the development of paired electrolysis involving CO₂RR are presented to inspire possible future research directions.