Energy advances最新文献

The electrocatalytic CO₂ reduction reaction (eCO₂RR) has the potential to effectively cut carbon emission. However, the activity and selectivity of eCO₂RR catalysts are topical due to the intricacy of the reaction components and mechanism. Herein, we have decorated silver and copper nanoparticles over carbon nanoflakes to achieve an Ag–Cu NPs/C system that enables selective reduction of CO₂ into CO. The catalyst is prepared by incorporating Ag nanoparticles into a Cu-BTC MOF (HKUST-1) and subsequent carbonization that alters the surface composition, with improved activity and faradaic efficiency (FE) towards selective CO₂ reduction. The evaluation of electrocatalytic performance reveals that the synthesized catalyst exhibits enhanced electrocatalytic activity and selectivity with a FE_CO of ∼ 90% at −0.79 V_RHE and a current density (j) of 44.15 mA cm⁻² compared to Ag-NPs and Cu/C. The durability test over 40 h confirms the outstanding stability of Ag–Cu NPs/C. The lower Tafel slope value of only 75 mV dec⁻¹ corresponds to the fast reaction kinetics on the surface of Ag–Cu NPs/C. The synthetic protocol in this work offers an easy approach to the betterment of a cost-effective electrocatalyst with improved FE.

Layered double hydroxides (LDHs) are clay networks with brucite (Mg(OH₂)) layers that are coupled with anions between the produced layers. The building structure of LDHs follows the formula [M_1−x²⁺M_x³⁺(OH)₂]^x+(Aⁿ⁻)_x/n·yH₂O, where M³⁺ and M² are trivalent and divalent cations in the structural units (sheets), respectively; x is the M³⁺ to (M²⁺ + M³⁺) cation ratio of the structure; and Aⁿ is an interlayer anion. LDHs can be created utilizing simple approaches that regulate the layer structure, chemical composition, and shape of the crystals generated by adapting production parameters. The first method of modifying LDH composites is through intercalation, involving the insertion of inorganic or organic precursors into their composition, which can then be employed for a variety of purposes. The next method is a simple physical mixing technique between the created LDHs and advanced materials, such as activated carbon, graphene and its derivatives, and carbon nanotubes, for utilization as base substances in energy storage, supercapacitors, photo- and electrocatalysts, water splitting, and toxic gas removal from the surrounding environment. The final strategy is the synthesis of polymer–LDH composites by inserting effective polymers during the manufacturing process of LDHs to create nano-composites that can be utilized for energy, fire retardant, gas barrier, and wastewater cleaning applications. LDHs are a type of fine chemical that can be designed to have a desired chemical structure and performance for various purposes, such as redox reactions, bromination, ethoxylation, aldol condensation, NO_x and SO_x elimination, and biofuel production. Because LDH substances are not harmful to the environment, their different applications are unique in terms of green chemistry as they are recyclable and eco-friendly catalysts. The present review investigated the various methods used to create LDHs and the improvement of the produced composites via enhanced temperature calcination; intercalation of their structures by small-, medium-, and high-nuclear anions; and support by carbon compounds. The evaluation methods and the best prospective uses, such as biofuel generation, catalysis, water splitting, charge transfer, and wastewater treatment, are comprehensively reported according to the most current studies, and the future directions of LDHs are highlighted.

With green hydrogen fuel continuing to be an important option for energy storage, studies on water-splitting reactions have attracted increasing attention. Within a multitude of parameters that have the potential to be explored to enhance water electrolysis, one of the most consequential factors is the development of an efficient electrocatalyst. The effectiveness of Co(III) corroles as electrocatalysts has largely been investigated in homogenous, non-aqueous or acidic environments. We report the use of heterogenized Co(III) corroles as bifunctional catalysts for water splitting under basic conditions, finding that the inclusion of alkyl chains on the ligand framework has a beneficial impact on electrocatalytic properties. Two new corroles have been isolated where the para positions in the fluorophenyl meso substituents of the parent cobalt(III) 5,10,15-tris(pentafluorophenyl)corrole Co(tpfpc)1 have been modified with heptyl, [Co(ttfphc)] 2 and dodecyl [Co(ttfpdc)] 3 amines via a nucleophilic aromatic substitution reaction. The electronic structure of these new complexes and properties of the resultant catalyst inks are significantly altered relative to the parent complex by the presence of the alkyl chains, as evidenced by changes in catalytic onset potentials and Tafel behavior during water splitting at pH 14. All catalysts were found to exhibit bifunctional behavior with reasonable stability, and the interactions of the alkyl amine groups with the supporting polymer in the catalyst ink have been found to have an important role in altering corrole aggregation and therefore Co active site accessibility during deposition of the catalyst inks.

A sustainable and readily available material, lignin protobind 2400, was upcycled to activated porous carbon (APC) compatible with post-combustion CO₂ capture. The effectiveness of the novel two-step physicochemical activation using KOH + CO₂ and ZnCl₂ + CO₂ was compared with that of the respective physical (only CO₂) and chemical activation (only KOH or ZnCl₂). The effect of carbonization conditions (N₂ or CO₂ purging) on the resulting APC properties and CO₂ adsorption performance was studied. The maximum BET surface area of 1480 m² g⁻¹ and the best CO₂ adsorption capacity of 5.68, 3.66, and 2.67 mmol g⁻¹ were observed at 0, 25, and 40 °C/1 bar, respectively. From the precursor to the final product, the APC yield falls within the range of 14.5–40.8 wt%. The APC derived from lignin exhibited better CO₂/N₂ selectivity. The isosteric heat of adsorption for all the APCs remained below 40 kJ mol⁻¹, which suggested a lower energy requirement during the regeneration. The excellent reusability with fluctuations of only 0.51% in the amount of CO₂ adsorbed over ten consecutive adsorption/desorption cycles highlights the APC's outstanding recyclability.

Transition metal oxyflourides have gained considerable interest as potential high-capacity cathode materials for Li-ion batteries. So far, commercialization has been hindered by the poor cyclability and fast degradation of this class of materials. The degradation process is believed to start at the surface and progresses toward the bulk. In this context, a suitable cathode-electrolyte interphase (CEI) appears to be a crucial factor where the formation of LiF has been identified as a key component promoting interfacial stability. In the current work, we make use of a combined density functional theory (DFT) and kinetic Monte Carlo (kMC) approach. Using DFT, we determine relevant interfaces between Li₂VO₂F and LiF. Rejection-free kMC simulations with parameters based on DFT are then used to probe the kinetics in the charging and discharging process of the Li₂VO₂F phase. We find that the interface formed by joining Li₂VO₂F and LiF via their most stable surface terminations has a modest but positive effect on the charging rate, where the LiF phase acts as a funnel that facilitates the Li extraction from the bulk of the Li₂VO₂F phase. However, the same interface has a severe impeding effect on the discharging of partially delithiated structures, which is orders of magnitudes slower than in the charging process. We find that the key property controlling the kinetics in the discharging process is the difference in stability of Li vacancies in the Li₂VO₂F and LiF phases.

Immobilization of metal nanoparticles (MNPs) with high density on a solid support is a crucial approach for their facile recovery and to counter aggregation problems. We have developed a simple technique by mediating the Diels–Alder “click reaction” using a deep eutectic solvent (DES) system. In this method, maleic anhydride (MA) was first covalently grafted onto the surface of reduced graphene oxide (rGO), which is further utilized as a seeding platform to grow dendrimers through the consecutive reactions of ethylenediamine (EDA) and MA. Finally, silver nanoparticles (AgNPs) were deposited in high density onto the dendrimers through visible light photoreaction. This method has excluded the use of harmful chemicals and an external reductant for the functionalization of rGO and deposition of AgNPs, respectively. Moreover, we have investigated the effect of dendrimers’ chain branching on the loading of AgNPs and evaluated their compound influence on the nitro-reduction reaction and antibacterial properties.

Over the past 20 years, metal–organic framework (MOF) nanosheets have garnered a great deal of interest in the fields of energy and environmental management because of their inherent extraordinary qualities. These qualities include the vast surface areas, nanoscale and tunable pore sizes, adaptable structures and functions, good thermal and chemical stability, high aspect ratios, more exposed accessible active sites, flexible functionality, high electrical conductivity, and optical transparency. An overview of the current advancements in the applications of MOF-based materials in environmental science and renewable energy is provided in this review. Precisely, the advancements, advantages, history and characterization of MOF-based materials are first presented and discussed. Next, we focused on the use of MOF-based materials in the fields of environmental cleaning and monitoring, particularly for the treatment of wastewater and air purification, and energy storage and conversion. We concluded by summarizing the findings on the current state-of-the-art advancements and sharing the perspectives on the prospects and problems facing future research on MOF-based materials.

Correction for ‘Copper and iron co-doping effects on the structure, optical energy band gap, and catalytic behaviour of Co₃O₄ nanocrystals towards low-temperature total oxidation of toluene’ by Hippolyte Todou Assaouka et al., Energy Adv., 2023, 2, 829–842, https://doi.org/10.1039/D3YA00082F.

Solid-state hydrogen storage technology ensures a safer storage method, eliminating the risks of leaks, boiling losses, and explosions in commercial applications. Based on earlier findings, alloying LiH with silicon (Si) yields substantial storage capacity while lowering the energy needed for absorption and decomposition. Herein, the work explores using the derivative of bulk Si (i.e., porous silicon nanowires (PSiNWs)) after mechanical milling with LiH to improve the thermodynamic properties and uptake capacity. The PSiNWs are synthesized by Ag metal-assisted chemical etching of the bulk Si substrate. Nanopores on the nanowires enhance gas physisorption by overlapping attractive fields from opposing pore walls. The large surface area (∼450 m² g⁻¹) of the PSiNWs provides maximum active sites for hydrogen storage. The hydrogen storage capacity of the LiH–PSiNW alloy is evaluated through pressure composition isotherms at different temperatures (400–500 °C range) and ∼4 MPa charging pressure. The maximum observed capacity, ∼3.95 wt%, occurs at 400 °C. The thermodynamic analysis signifies the uniform absorption and desorption enthalpy after alloying LiH with PSiNWs. Hydrogen absorption and desorption enthalpies of ∼118 kJ mol⁻¹ H₂ and ∼115 kJ mol⁻¹ H₂ demonstrate a reduced energy requirement compared to individual LiH. The phase formation and variations before and after hydrogenation are studied by X-ray diffraction. This work investigates using Si nanostructures and light metal hydrides for enhanced hydrogen storage and cyclic functionalities, serving as both a storage material and catalyst.

In response to the growing demand for battery materials, researchers explore alternative resources with a focus on sustainability. Among these, organic electrode materials including porphyrins have emerged as promising candidates due to their advantageous properties, such as rapid charging capabilities and high energy densities. However, despite their potential, the precise charging mechanism of these alternatives remains elusive. To address this gap, our study delved into copper porphyrins, with a primary focus on [5,15-bis(ethynyl)-10,20-diphenylporphinato] copper(II) (CuDEPP). Employing synchrotron X-ray absorption spectroscopy in operando mode, we probed the evolution in chemical and electronic structure of Cu in CuDEPP. Our findings unequivocally demonstrate the participation of copper as a redox center during reversible charge storage, shedding light on its superior electrochemical performance. Furthermore, a combined approach involving extended X-ray absorption fine structure (EXAFS) studies and theoretical calculations provided deeper insights into the observed structural distortion during the charge storage process. Notably, our results support the hypothesis that redox processes, specifically those involving the aromatic porphyrin ring, drive the electrochemical activity of CuDEPP. In summary, our investigation offers important insights into the charging mechanism of copper porphyrins an essential step toward advancing sustainable organic materials for batteries.