材料导报:能源(英文)最新文献

The electrochemical reduction of CO₂ (CO₂ER) into the renewable and sustainable green fuels, such as low-carbon alcohols, is one of several workable strategies. CO₂ER can be combined with renewable electricity to transform intermittent energy sources (such as wind, hydro, and solar) into a fuel that can be stored until it is ready to be used. The intrinsic characteristics of the employed catalyst have a significant and substantial effect on the efficiency of CO₂ER and the ensuing economic viability. The paradigmatic multicarbon alcohol catalysts should increase the concentration of ^∗CO in the reaction environment, stabilize the key intermediate products during the reaction, and facilitate the C–C coupling interaction. Since graphene has a large surface area and exceptional conductivity, it has been used as a support for active phases (nanoparticles or nanosheets). It is possible for graphene to enhance charge transport and accelerate CO₂ conversion through its electronic and structural coupling effects. At the interface, a synergy can be produced that improves CO₂ER by increasing ^∗CO adsorption, intermediate binding, and stability. This article focuses on recent advancements in graphene-based catalysts that promote CO₂ER to alcohols. Likewise, this paper also describes and discusses the key role graphene plays in catalyzing CO₂ER into alcohols. Finally, we hope to provide future ideas for the design of graphene-based electrocatalysts.

Electrocatalytic CO₂ reduction reaction (CO₂RR), driven by clean electric energy such as solar and wind, can not only alleviate environmental greenhouse effect stemming from excessive CO₂ emissions, but also realize the storage of renewable energy, for it guarantees the production of value-added chemicals and fuels. Among CO₂RR products, formic acid shows great advantages in low energy consumption and high added-value, and thus producing formic acid is generally considered as a profitable line for CO₂RR. Bismuth-based electrocatalysts exhibit high formic acid selectivity in CO₂RR. Herein, we review the recent progress in bismuth-based electrocatalysts for CO₂RR, including material synthesis, performance optimization/validation, and electrolyzers. The effects of morphologies, structure, and composition of bismuth-based electrocatalysts on CO₂RR performance are highlighted. Simultaneously, in situ spectroscopic characterization and DFT calculations for reaction mechanism of CO₂RR on Bi-based catalysts are emphasized. The applications and optimization of electrolyzers with high current density for CO₂RR are summarized. Finally, conclusions and future directions in this field are prospected.

Electrochemical carbon dioxide reduction reaction (CO₂RR) provides an attractive approach to carbon capture and utilization for the production high-value-added products. However, CO₂RR still suffers from poor selectivity and low current density due to its sluggish kinetics and multitudinous reaction pathways. Single-atom catalysts (SACs) demonstrate outstanding activity, excellent selectivity, and remarkable atom utilization efficiency, which give impetus to the search for electrocatalytic processes aiming at high selectivity. There appears significant activity in the development of efficient SACs for CO₂RR, while the density of the atomic sites remains a considerable barrier to be overcome. To construct high-metal-loading SACs, aggregation must be prevented, and thus novel strategies are required. The key to creating high-density atomically dispersed sites is designing enough anchoring sites, normally defects, to stabilize the highly mobile separated metal atoms. In this review, we summarized the advances in developing high-loading SACs through defect engineering, with a focus on the synthesis strategies to achieve high atomic site loading. Finally, the future opportunities and challenges for CO₂RR in the area of high-loading single-atom electrocatalysts are also discussed.

Electrochemical reduction of CO₂ (CO₂RR) coupled with renewable electrical energy is an attractive way of upgrading CO₂ to value-added chemicals and closing the carbon cycle. However, CO₂RR electrocatalysts still suffer from high overpotential, and the complex reaction pathways of CO₂RR often lead to mixed products. Early research focuses on tuning the binding of reaction intermediates on electrocatalysts, and recent efforts have revealed that the design of electrolysis reactors is equally important for efficient and selective CO₂RR. In this review, we present an overview of recent advances and challenges toward achieving high activity and high selectivity in CO₂RR at ambient conditions, with a particular focus on the progress of CO₂RR electrocatalyst engineering and reactor design. Our discussion begins with three types of electrocatalysts for CO₂RR (noble metal-based, none-noble metal-based, and metal-free electrocatalysts), and then we examine systems-level strategies toward engineering specific components of the electrolyzer, including gas diffusion electrodes, electrolytes, and polymer electrolyte membranes. We close with future perspectives on catalyst development, in-situ/operando characterization, and electrolyzer performance evaluation in CO₂RR studies.

Continuous accumulation and emission into the atmosphere of anthropogenic carbon dioxide (CO₂), a major greenhouse gas, has been recognized as a primary contributor to climate change associated with the global warming and acidification of oceans. This has led to drastic changes in the natural ecosystem, and hence an unhealthy ecological environment for human society. Thus, the effective mitigation of the ever increasing CO₂ emission has been recognized as the most important global challenge. To achieve zero carbon footprint, novel materials and approaches are required for potentially reducing the CO₂ release, while our current fossil-fuel-based energy must be replaced by renewable energy free from emissions. In this paper, porous carbons with hierarchical pore structures are promising for CO₂ adsorption and electrochemical CO₂ reduction owing to their high specific surface area, excellent catalytic performance, low cost and long-term stability. Since efficient gas-phased (electro)catalysis involves the access of reactants to active sites at the gas-liquid-solid triple phase, the hierarchical porous carbon materials possess multiple advantages for various CO₂-related applications with enhanced volumetric and gravimetric activities (e.g., CO₂ uptake and current density) for practical operations. Recent studies have demonstrated that porous carbon materials exhibited notable activities as CO₂ adsorbents and provided facile conducting pathways and mass diffusion channels for efficient electrochemical CO₂ reduction even under the high current operation conditions. Herein, we summarize recent advances in porous carbon materials for CO₂ capture, storage, and electrochemical conversion. Prospectives and challenges on the rational design of porous carbon materials for scalable and practical CO₂ capture and conversion are also discussed.

Seeking and developing efficient CO₂ reduction reaction (CO₂RR) electrocatalysts is a hot topic in this era of global warming. Among material candidates for sustainable and cost-effective applications, metal sulfides have attracted attention as promising nature-inspired materials due to multiple adsorption sites which are enhanced by the covalent character of sulfur. This article summarizes the current status regarding the utilization and development of metal sulfide materials as CO₂RR electrocatalysts. First, the research background and basic principles of electrochemical CO₂RR are introduced. Next, an overview of the main obstacles to developing efficient CO₂RR electrocatalysts is presented. The section is followed by a summary of the empirical evidence supporting the application of metal sulfides as CO₂RR electrocatalysts beside nature-inspired motivation. The summary of synthesis methods of various metal sulfides is also presented. Furthermore, the paper also highlights the recent works on metal sulfide as efficient CO₂RR including the undertaking strategy on the activity enhancement, and finally, discusses the challenges and prospect of metal sulfides-based CO₂RR electrocatalysts. Despite recent efforts, metal sulfides remain relatively unexplored as materials for CO₂RR electrocatalytic applications. Therefore, this review aims to stimulate novel ideas and research for improved catalyst designs and functionality.

Electrochemical CO₂ reduction to C₂H₄ can provide a sustainable route to reduce globally accelerating CO₂ emissions and produce energy-rich chemical feedstocks. However, the poor selectivity in C₂H₄ electrosynthesis limits its implementation in industrially interesting processes. Herein, we report a composite structured catalyst composed of Ag and Cu₂O with different crystal faces to achieve highly efficient reduction of CO₂ to C₂H₄. The catalyst composed of Ag and octahedral Cu₂O enclosed with (111) facet exhibits the best CO₂ electroreduction performance, with the Faradaic efficiency (FE) and partial current density reaching 66.8% and 17.8 mA cm⁻² for C₂H₄ product at −1.2 V_RHE in 0.5 M KHCO₃, respectively. Physical characterization and electrochemical test analysis indicate that the high selectivity for C₂H₄ product stems from the synergistic effect of crystal faces control engineering and tandem catalysis. Specifically, Ag can provide optimal availability of CO intermediate by suppressing hydrogen evolution; subsequently, C–C coupling is promoted on the intimate surface of Cu₂O with facet-dependent selectivity. The insights gained from this work may be beneficial for designing efficient multicomponent catalysts for improving the selectivity of electrochemical CO₂ reduction reaction to generate C₂₊ products.

Electrocatalytic reduction of CO₂ into fuels and commodity chemicals has emerged as a potential way to balance the carbon cycle and produce reusable carbon fuels. However, the challenges of the competing reaction of hydrogen evolution reaction, low CO₂ concentration on the catalyst surface and the diversity of products significantly limit the catalytic activity and selectivity. Hereby, metal nanomaterials, protected by surface stabilizing ligands, have been widely studied in the field of CO₂ reduction due to their structural diversity and outstanding physical and chemical properties. Nevertheless, the surface organic ligands may lower the activity of electrocatalysts, while ligand detachment would cause original structure collapse and selectivity reduction. Therefore, the implementation of strategies based on designing nano-metal catalysts to promote CO₂ reduction from the perspective of metals and ligands has attracted increasing attention. Herein, we highlight the recent studies on the regulation of surface ligands of metal clusters and metal nanoparticles to promote CO₂ electroreduction. Meanwhile, we further summarize the relationship between the surface structure of metal nanocatalysts and the catalytic performance for CO₂ reduction reaction (CO₂RR). This mini review offers an inspiration in remaining challenges and future directions on nano-metal catalysts for electrocatalytic CO₂RR.