ChemSusChem最新文献

The emergence of visible-light photocatalytic frameworks provides a sustainable technology for dealing with CO2 greenhouse gas. Herein, the solvothermal reaction of copper(I) cyclic trinuclear complex (Cu-CTC) with 2,5-dihydroxyterephthalaldehyde (2,5-DHTA) or 3,3'-dihydroxy-[1,1'-biphenyl]-4,4'-dicarbaldehyde (3,3'-DHBDA) led to two crystalline hcb topological copper(I)-organic frameworks USTB-48 and USTB-49, respectively. The post-cobaltization of 2-(benzylideneamino)phenol units in these two frameworks, providing the active catalytic centers in obtained USTB-48(Co) and USTB-49(Co) for photocatalysis of CO2 reduction. The parent frameworks and post-modificated species have been thoroughly characterized through powder X-ray diffraction analysis and various spectroscopies. The combination of trinuclear copper units and single cobalt centers is able to achieve the CO generation rate up to ca. 8451 μmol·g-1·h-1 and 96% selectivity for USTB-48(Co).

Compared to inorganic semiconductors, organic semiconductors (OSCs) exhibit lower permittivity and carrier mobility. This is primarily attributed to their weaker van der Waals forces and the significant structural and energetic disorder, ultimately impeding the commercial application of organic photovoltaics (OPVs). However, the introduction of n-type or p-type dopants offers a solution. These dopants effectively eliminate intrinsic traps in OSCs through trap-filling techniques, elevating carrier concentration and mobility, and consequently enhancing overall performance. This article delves into the systematic exploration of n-type and p-type dopant applications in OPVs. It encompasses doping mechanisms, commonly used n-type and p-type dopants, doping methodologies, the strategic distribution of dopants and the effect of doping on device performance. Ultimately, this concept strives to offer invaluable insights and guidance for advancing OPV performance via doping techniques.

Developing metal-free catalysts is critical to addressing the issues of susceptibility to poisoning and deficient durability in the electrocatalysis of metal-based materials for CO2 reduction reaction (CO2RR). Herein, N-doped carbon nanoparticles (NCs) with a specific ratio of graphitic/pyrrolic N, high specific surface area, and abundant nanopores are synthesized by pyrolyzing a Cu and Zn co-coordinated polymer with bis(imino)-pyridine ligands. Results demonstrate that precise co-incorporation of Cu and Zn in the precursor effectively modulates the N doping species and ratios of NCs, as well as the pore structure, resulting in significantly distinct CO2RR behaviors. The NCs synthesized by the precursor with the ratio of Zn and Cu ions (1:4), featuring graphitic-N and pyrrolic-N in the ratio of 2:1 and high specific surface area (896.8 m2 g-1), exhibit a low onset potential of -0.4 VRHE, an exceptional CO Faradaic efficiency of 96.1%, and a power density of 0.8 mW cm-2 in a Zn-CO2 battery. Theory calculations reveal that regulating the graphitic/pyrrolic N ratio can redistribute the localized atoms' charge density, which enhances the adsorption of intermediate COOH* and mobilizes multiple active atomic sites favoring CO2RR. The discovery in this work provides a new understanding for the design of advanced metal-free CO2RR electrocatalysts.

This study highlights the effectiveness of hydrodeoxygenation (HDO) in converting lignin oils from Eucalyptus, Poplar, and Pine wood, derived from reductive catalytic fractionation (RCF), into renewable cycloalkanes for jet fuel. Using a low-cost Ni2P/SiO2 catalyst, the process achieved yields of 91 %, 83 %, and 75 % of renewable cycloalkanes respectively. In addition, the process exhibited high selectivity towards a specific range of hydrocarbons mostly present in aviation fuel (C9 to C15), with values of 70%, 60% and 62% for the three feedstocks, respectively, showcasing the potential for high-value fuel production. The research underscores the importance of modifying lignin oil properties through various chemo-catalytic biorefining pathways, which significantly influence the quality of the produced blend via HDO. These findings provide valuable insights into optimizing feedstock characteristics for improved jet-range hydrocarbon production.

Manganese dioxide (MnO2) cathodes are widely studied for aqueous zinc-ion batteries (AZIBs) because of their high theoretical capacity and energy density. However, the formation of "dead manganese" and Mn2+ dissolution during cycling lead to active materials loss and significant capacity decay, impeding their practical application. In this study, a novel oxygen-containing group-functionalized carbon nanotube supporter loaded with Bi2O3 (cCNTs-Bi) was constructed to improve the cyclic stability of MnO2 cathodes. The results revealed that the oxygen-containing functional groups on cCNTs-Bi facilitate the deposition of Mn2+ ions from the electrolyte through electrostatic attraction. More importantly, the introduction of Bi3+ into MnO2 to form Bi-O-Mn bonds weakens the interaction between the intercalated cations and oxygen atoms to ensure the diffusion of intercalated cations and reaction reversibility, thus reducing the accumulation of inactive phases such as ZnMn2O4 and zinc hydroxide sulfate. Consequently, cCNTs-Bi demonstrated outstanding stability over 2000 cycles. When combined with MnO2, the composite retaining a discharge capacity of 295.5 mAh g-1 after 120 cycles at 0.2 A g-1, and of 104.5 mAh g-1 after 1000 cycles at 1 A g-1. This study clearly elucidate the dissolution deposition mechanism of MnO2, providing theoretical support and guidance for enhancing the properties of MnO2.

Infrared thermal activation (IRTA) is considered an efficient approach to accelerate reaction rates. We report the first example of application of IRTA to achieve surface functionalization of cellulose nanocrystals (CNCs) in solvent-less conditions with epoxidized linoleic acid (ELA), synthesized by enzymatic approach using CaLB (lipase B from Candida antarctica) and H2O2. The final goal is to enhance the hydrophobicity of cellulosic surfaces of bio-based materials, with potential application in the coating industry. The reaction is extended to delignified rice husk (d-RH), a largely available agro-waste and a cost-effective cellulose-rich biomass. Solid-state cross polarization magic angle spinning (CP MAS) 13C nuclear magnetic resonance (NMR) analyses, liquid state 1H-NMR, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FE-SEM) and X-ray diffractometry (XRD) data support a fine structural characterization of both functionalized CNCs and d-RH to assess the effectiveness of the strategy used and the characteristics of the materials. Water contact angle measurements confirm the changed surface chemistry and the occurrence of hydrophobization on CNCs and d-RH. This efficient and sustainable method can have potential application in industrial-scale environments to change the properties of ligno-cellulosic biomass and bio-based materials in general.

Owing to unique redox behaviour and structural versatility, cobalt hydroxide/cobalt oxide-based nanomaterials have emerged as promising materials for energy storage. Relation between coordination environment of Co2+ and its effect on electrochemical behaviour remains unexplored. α-Co(OH)₂ contains Co2+ in octahedral coordination (Co2+Oh). Engineering Co2+ coordination to tetrahedral (Co2+Td) can significantly affect supercapacitive performance. Herein, a simple homogeneous precipitation method is used to achieve this transformation. At low concentration of Co salt (5 mmol), pink-coloured α-Co(OH)₂ nanoflakes (Co(OH)₂-PP) are formed with only Co2+Oh,  whereas at higher concentration (50 mmol), blue colored α-Co(OH)₂ nanorods (Co(OH)₂-BP) are formed with both Co2+Oh and Co2+Td. The maximum specific capacity reached 167.5 C g-1 for Co(OH)₂-BP which showed ~ 200 %  increment as compared to α-Co(OH)₂-PP at 10 mV s-1. α-Co(OH)₂ was thermally decomposed to obtain Co3O4 nanoparticles. The specific capacity of Co₃O₄ nanoparticles derived from Co(OH)₂-BP and Co(OH)₂-PP are 136.3 C g-1 and 110.7 C g-1, respectively, which showed a marginal increase in specific capacity. An asymmetric supercapacitor device based on Co(OH)₂-BP/rGO exhibits peak energy density of 14.6 W h kg-1 and peak power density of ~12 kW kg-1. Insights from this study will significantly impact development of advanced energy storage materials.

Electrochemical nitrate reduction reaction is a sustainable pollutant remedy tool and offers wider application for green ammonia production. The overall electrochemical reaction mostly depends on the electrode material, which thus requires a highly active and efficient electrocatalyst that is both green and cost-effective. Here, we show electropolymerized cobalt porphyrin-containing tetrakis-biphenyl-bis(bithiophene) entities as efficient electrocatalysts for ammonia production via electrochemical nitrate reduction. The newly developed electrocatalyst was able to achieve a high Faradaic efficiency of 92.7% at -0.4 V vs. Ag/AgCl for ammonia production with very low production of other side products and exhibited long-term durability without any significant physical and chemical deterioration. Experimental findings were well-supported by DFT calculations.

Dual photocatalysis converts renewable solar energy into clean fuel and concomitantly value-added chemical synthesis through hydrogen generation and selective organic transformation, using semiconductor catalysts. The catalytic activity of solitary component semiconductor photocatalysts is impeded by their inefficient charge separation and transfer. We, herein, present a facile method, electrostatic assembly, to create hybrid photocatalysts that consist of CdS quantum dots and non-conjugated poly(ionic liquid)s including poly(diallyl dimethyl ammonium bromide) (P(DADMA)) and poly(1-ethyl-3-vinylimidazolium bromide) (P(VEIM)). Poly(ionic liquid)s acted as electron donors to CdS, resulting in an increase in charge separation and transportation in CdS/P(DADMA) and CdS/P(VEIM) hybrids, as demonstrated by experimental and computational results. The optimal photocatalysis of benzyl alcohol (BA) in water was achieved by CdS/P(DADMA) under 12-hour LED370 illumination in a nitrogen-atmosphere. This process produced 12.8 mmol gcat-1 h-1 of H2 and 12.5 mmol gcat-1 h-1 of racemic hydrobenzoin (HB) with 99% selectivity. In photocatalysis, CdS/P(DADMA) outperformed CdS/P(VEIM) and CdS by a significant margin. Our photocatalytic system enabled the BA-to-HB conversion in water, of which the reaction is commonly sluggish due to a mass transfer constraint. The insightful DFT calculation confirmed that poly(ionic liquid)s may stabilize active intermediate species in the process, significantly enhancing photogenerated charge expedition and photocatalytic performance.

Plastic waste management is a major global concern as the production of these materials continues to increase without proportional advancements in recycling technologies. Dissolution-precipitation is a promising emerging technology, offering a simple yet effective process to manage complex materials that often go unrecycled, while also recovering high-quality polymers. The success of this technology largely depends on the careful design and selection of solvents. This perspective discusses the most used methods used to screen and select these solvents prior to experimental tests, and provides an overview of the solvents tested in dissolution and precipitation steps of common polymers. Recent advances improved the accuracy and applicability of common and novel solvent screening methods, namely Hansen Solubility Parameters, COSMO-RS, and Machine Learning models. Additionally, the compilation of all solvents reported for dissolution-precipitation of common polymers clearly highlighted the scarcity of studies using alternative green solvents and the need to deeper understand the dissolution-precipitation processes as a whole. This should lead to the development of more sustainable circular polymer recycling processes, which should be regarding Life Cycle Analysis (LCA) and economic assessments.