Industrial Chemistry & Materials最新文献

Efficient utilization of lignocellulosic biomass to substitute for fossil resources is an effective way to promote the sustainable development of current society. Numerous lignocellulose valorization routes for the production of value-added chemicals and fuels have been explored. Herein, we overview the catalytic reaction routes, reaction types and key steps involved in the selective preparation of various important products from lignocellulose. The information can facilitate the development of robust and selective catalytic systems to address the challenges in the major reaction steps. We present four catalytic conversion route maps starting from cellulose (including 5-hydroxylfurfural, HMF), hemicellulose and lignin, respectively. The reaction route for the important platform molecules of HMF and furfural, passing through critical intermediates to value-added chemicals and aviation fuels, is also highlighted. It provides a clear and concise panorama for people interested in this field and facilitates identifying the products or processes of interest with up-to-date research developments. We also put forward the current issues for the large-scale valorization of lignocellulose and the possible resolution strategies, focusing on the rational design of active and robust heterogeneous catalysts.

Keywords: Biomass; Lignocellulose valorization; Catalytic conversion network; Reaction routes; Renewable chemicals.

A graphical abstract is available for this content

The increasing CO₂ emission, as the chief culprit causing numerous environmental problems, could be addressed by the electrochemical CO₂ reduction (CO₂R) to the added-value carbon-based chemicals. Ionic liquids (ILs) as electrolytes and co-catalysts have been widely studied to promote CO₂R owing to their unique advantages. Among the potential products of CO₂R, those only containing one carbon atom, named C1 products, including CO, CH₃OH, CH₄, and syngas, are easier to achieve than others. In this study, we first summarized the research status on CO₂R to these C1 products, and then, the state-of-the-art experimental results were used to evaluate the economic potential and environmental impact. Considering the rapid development in CO₂R, future scenarios with better CO₂R performances were reasonably assumed to predict the future business for each product. Among the studied C1 products, the research focuses on CO, where satisfactory results have been achieved. The evaluation shows that producing CO via CO₂R is the only profitable route at present. CH₃OH and syngas of H₂/CO (1 : 1) as the targeted products can become profitable in the foreseen future. In addition, the life cycle assessment (LCA) was used to evaluate the environmental impact, showing that CO₂R to CH₄ is the most environmentally friendly pathway, followed by the syngas of H₂/CO (2 : 1) and CO, and the further improvement of the CO₂R performance can make all the studied C1 products more environmentally friendly. Overall, CO is the most promising product from both economic and environmental impact aspects.

Keywords: Electrochemical-CO₂-reduction; Ionic-liquids; C1-product; Economic-evaluation; Environmental-impact.

Electrocatalytic technology opens a new path to solve the existing problems in fossil fuel consumption and environmental pollution as well as efficient energy use. Metal–organic frameworks (MOFs), a class of crystalline porous materials with high specific surface area, high porosity and customizable structures, have emerged as promising electrocatalysts. However, their inherently low electrical conductivity and stability greatly hinder their further applications. Therefore, strategies such as synthesizing two-dimensional conductive MOFs, designing unsaturated metal sites, and building MOF nanoarrays have been developed to enhance the conductivity and catalytic reaction transfer rates of MOFs, accompanied by the rational designs of MOFs for improving their stability. In this review, the applications of MOF-based electrocatalysts in the hydrogen evolution reaction (HER), hydrogen oxidation reaction (HOR), oxygen evolution reaction (OER), oxygen reduction reaction (ORR) and nitrogen reduction reaction (NRR) are presented in detail with the classification of monometallic MOFs, bimetallic MOFs, MOF-based composites and MOFs as supports. In addition, the relationship between the structure and performance is discussed through DFT calculations used in related work. Finally, future challenges and application prospects of MOFs in electrocatalysis are highlighted.

Keywords: Metal–organic frameworks; Electrocatalyst; Catalytic performance; Catalysis; Energy conversion.

The growing demand for portable electronic devices, electric vehicles, and large-scale advanced energy storage has aroused increasing interest in the development of high energy density lithium batteries. The electrolyte is an important component of lithium batteries and is an essential part of performance and safety improvements. Commercially available electrolytes mainly consist of lithium salts and organic carbonate solvents that are prone to decomposition due to their narrow electrochemical windows and tend to react with lithium metal anodes forming an unstable solid electrode/electrolyte interface (SEI). In particular, the flammability of organic solvents raises concerns about battery safety. Ionic liquid/poly(ionic liquid) (IL/PIL)-based electrolytes enable batteries with good safety, high energy/power density and long-term stability. This review focuses on the applications of IL/PIL-based liquid, quasi-solid, and solid electrolytes and electrolyte additives in lithium batteries. The perspectives and challenges of IL/PIL electrolytes in the field of lithium batteries are also proposed.

Keywords: Ionic liquid; Poly(ionic liquid); Lithium battery; Solid electrolyte; Quasi-solid electrolyte; Additive.

The influences of increasing the number of d-electrons in the single metal (Fe-like) substituted (111)_n surface of γ-Al₂O₃ on its possible catalytic effects were explored. The energetic properties, local structures, and in-site electron configurations of the most active tri-coordinated Co and Ni single-site (111)_n surface of γ-Al₂O₃ have been studied using the density functional theory (DFT) approach under periodic boundary conditions. The replacement of Al by a Co or Ni atom on the I position of the (111)_n surface leads to significant elongations of metal–O distances. The energy released from the substitution process on the Al_I site of the (111)_n surface follows the sequence Ni_I (164.85 kcal mol⁻¹) > Co_I (113.17 kcal mol⁻¹) > Fe_I (44.30 kcal mol⁻¹). The triplet and quintet (ground state) of the Co_I substituted complex are energy degenerate. Also, the doublet and quartet (ground state) of the Ni_I substituted complex have the same stable energy. This energy degeneracy comes from the α–β electron flipping on the p-orbital of the neighboring O that is next to the substituted Co_I or Ni_I site on the (111)_n surface of γ-Al₂O₃. Different from the Fe_I substituted single-site (111)_n surface, in which the electron configuration of Fe_I varies according to its spin-multiplicity state, substituted Ni_I has a unique d⁸ electron configuration in all three spin states, and similarly, Co_I has a unique d⁷ electron configuration in all three open shell spin states. An increase of the population of d-electrons in the single metal substituted (111)_n surface of γ-Al₂O₃ is likely to provide a more stable electron configuration in the metal catalytic center.

Keywords: Co substituted surface of γ-Al₂O₃; Ni substituted surface of γ-Al₂O₃; (111)_n surface; Periodic boundary DFT approach; Metal catalytic center.

Ionic liquids (ILs) provide a promising way for efficient absorption and separation of ammonia (NH₃) due to their extremely low vapor pressures and adjustable structures. However, the understanding of absorption mechanisms especially in terms of theoretical insights is still not very clear, which is crucial for designing targeted ILs. In this work, a universal method that integrates density functional theory and molecular dynamic simulations was proposed to study the mechanisms of NH₃ absorption by protic ionic liquids (PILs). The results showed that the NH₃ absorption performance of the imidazolium-based PILs ([BIm][X], X= Tf₂N, SCN and NO₃) is determined by not only the hydrogen bonding between the N atom in NH₃ and the protic site (H–N³) on the cation but also the cation–anion interaction. With the increase in NH₃ absorption capacity, the hydrogen bonding between [BIm][Tf₂N] and NH₃ changed from orbital dominated to electrostatic dominated, so 3.0 mol NH₃ per mol IL at 313.15 K and 0.10 MPa was further proved as a threshold for NH₃ capacity of [BIm][Tf₂N] by the Gibbs free energy results, which agrees well with the experimental results. Furthermore, the anions of [BIm][X] could also compete with NH₃ for interaction with H-N³ of the cation, which weakens the interaction between the cation and NH₃ and then decreases the NH₃ absorption ability of PILs. This study provides further understanding on NH₃ absorption mechanisms with ILs, which will guide the design of novel functionalized ILs for NH₃ separation and recovery.

Keywords: Protic ionic liquids; NH₃ absorption; Interaction mechanisms; Simulation calculations.

A series of poly(alkyl-biphenyl pyridinium) anion exchange membranes (AEMs) with a hydrophobic side chain were prepared for mono-/divalent anion separation using electrodialysis (ED). A poly(alkyl-biphenyl pyridinium) polymer was synthesized via superacid-catalyzed polymerization, and then quaternization was conducted using Menshutkin reactions with 1-bromopentane. The obtained quaternized product had excellent solubility in common organic solvents, making it flexible to form homogeneous membranes by a solution casting method. The introduction of a hydrophobic side chain resulted in a microphase separation structure in the membrane, which is favorable to the active transport of Cl⁻ (higher Cl⁻ flux of up to 3.37 mol m⁻² h⁻¹ at a 10 mA cm⁻² current density) compared with that of SO₄²⁻ ions giving a high permselectivity of 11.9 in a mixed salt (NaCl/Na₂SO₄) system. In addition, the prepared membrane exhibited excellent alkaline stability in successive ED tests. It showed an OH⁻ flux of up to 3.6 mol m⁻² h⁻¹ with a permselectivity of 361.2 between OH⁻ and WO₄²⁻, which is much higher than that of Neosepta ACS membrane. The ED results manifest that the poly(alkyl-biphenyl pyridinium) AEMs can be promising candidates for practical mono-/divalent anion separation in industry.

Keywords: Superacid-catalyzed polymerization; Anion exchange membrane; Mono-/divalent anion separation; Electrodialysis; Permselectivity.

Electroreduction of small molecules such as CO₂, N₂, and NO₃⁻ is one of the promising routes to produce sustainable chemicals and fuels and store renewable energy, which could contribute to our carbon neutrality goal. Emerging multicomponent electrocatalysts, integrating the advantages of individual components of catalysts, are of great importance to achieve efficient electroreduction of small molecules via activation of inert bonds and multistep transformation. In this review, some basic issues in the electroreduction of small molecules including CO₂, N₂, and NO₃⁻ are briefly introduced. We then discuss our fundamental understanding of the rule of interaction in multicomponent electrocatalysts, and summarize three models for multicomponent catalysts, including type I, “a non-catalytically active component can activate or protect another catalytic component”; type II, “all catalytic components provide active intermediates for electrochemical conversion”; and type III, “one component provides the substrate for the other through conversion or adsorption”. Additionally, an outlook was considered to highlight the future directions of multicomponent electrocatalysts toward industrial applications.

Keywords: Green chemistry; Green carbon science; Electrocatalysis; Synergetic effect.

Supercapacitors are highly valued energy storage devices with high power density, fast charging ability, and exceptional cycling stability. A profound understanding of their charging mechanisms is crucial for continuous performance enhancement. Electrochemical quartz crystal microbalance (EQCM), a detection means that provides in situ mass change information during charging–discharging processes at the nanogram level, has received greatly significant attention during the past decade due to its high sensitivity, non-destructiveness and low cost. Since being used to track ionic fluxes in porous carbons in 2009, EQCM has played a pivotal role in understanding the charging mechanisms of supercapacitors. Herein, we review the critical progress of EQCM hitherto, including theory fundamentals and applications in supercapacitors. Finally, we discuss the fundamental effects of ion desolvation and transport on the performance of supercapacitors. The advantages and defects of applying EQCM in supercapacitors are thoroughly examined, and future directions are proposed.

Keywords: EQCM; Supercapacitors; Charging mechanisms; Quantitative characterization.