Fabrication of an Au-doped Cu/Fe oxide-polymer core-shell nanoreactor with chemodynamic and photodynamic dual effects as potential cancer therapeutic agents

Nanoparticles are widely used in biomedical applications and cancer treatments due to their minute scale, multi-function, and long retention time. Among the various nanoparticles, the unique optical property derived from the localized surface plasmon resonance effect of metallic nanoparticles is a primary reason that metallic nanoparticles are researched and applied. Copper and Iron nanoparticles have the potential to generate hydroxyl radicals in excess H₂O₂ via Fenton or Fenton-like reactions. On the other hand, gold nanoparticles equipped with a photosensitizer can transfer the energy of photons to chemical energy and enhance the production of singlet oxygen, which is suitable for cancer treatment. With the actions of these two reactive oxygen species in the tumor microenvironment, cell apoptosis can further be induced. In this work, we first synthesized dual metal nanoparticles with poly[styrene-alt-(maleic acid, sodium salt)(Cu ferrite oxide-polymer) by a simple one-step hydrothermal reduction reaction. Then, gold(III) was reduced and doped into the structure, which formed a triple metal structure, Au-doped Cu ferrite nanoparticles (Au/Cu ferrite oxide-polymer NPs). The metal ratio of the product could be controlled by manipulating the Fe/Cu ratio of reactants and the sequence of addition of reactants. The core-shell structure was verified by transmission electron microscopy. Moreover, the hydroxyl radical and singlet oxygen generation ability of Au/Cu ferrite oxide-polymer was proved. The chemodynamic and photodynamic effect was measured, and the in vitro ROS generation was observed. Furthermore, the behavior of endocytosis by cancer cells could be controlled by the magnetic field. The result indicated that Au/Cu ferrite oxide-polymer core-shell nanoreactor is a potential agent for chemodynamic/photodynamic synergetic therapy.

Advancements in the Conversion of Lipid-Rich Biowastes and Lignocellulosic Residues into High-Quality Road and Jet Biofuels Using Nanomaterials as Catalysts

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to sustainably use lignocellulosic residues. These resources must be treated through a deoxygenation process and subsequent upgrading processes to obtain high-quality road and jet biofuels. Accordingly, in this review, we explore recent advancements in the deoxygenation of oleochemical and lignocellulosic feedstocks in the absence of hydrogen to produce high-quality road and jet biofuels, mainly focusing on the use of nanomaterials as catalysts and the valorization of lipid-rich biowastes and lignocellulosic residues. As a result, we found that regardless of the catalyst particle size, the coexistence of basic sites and weak/medium acid sites is highly important in catalytic systems. Basic sites can enhance the removal of oxygenates via decarboxylation and decarbonylation reactions and inhibit coke formation, while weak/medium acid sites can enhance the cracking reaction. Additionally, the extraction of value-added derivatives from lignocellulosic residues and their subsequent upgrade require the use of advanced methods such as the lignin-first approach and condensation reactions.

Synthesis of Highly Active Carbon-encapsulated Ni2P Catalysts by One-step Pyrolysis–phosphidation for Hydrodeoxygenation of Phenolic Compounds

Hydrodeoxygenation (HDO) of phenolic compounds is a promising technology to convert biomass materials to value-added chemicals and fuels. However, the development of highly efficient catalysts remains a great challenge. In...

Lignin-to-chemicals: Application of catalytic hydrogenolysis of lignin to produce phenols and terephthalic acid via metal-based catalysts

Lignin is the only renewable aromatic material in nature and contains a large number of oxygen-containing functional groups. High-value and green utilization of "lignin-to-chemicals" can be realized via using lignin to produce fine chemicals such as phenols and carboxylic acids, which can not only reduce the waste of lignin in the process of lignocellulosic biomass treatment, but gradually make the substitution of traditional fossil fuels come true. The hydrogenolysis process under catalysis of metal catalyst has high product selectivity and less impurity, which is suitable for the production of same type or single fine chemicals. Hydrogenolysis of lignin via metal catalysts to produce lignin oil, and further modification of functional groups (e.g. methoxyl, alkyl and hydroxyl group) of depolymerized monomers in the bio-oil to yeild phenols and terephthalic acid are reviewed, and catalytic mechanisms are briefly summarized in this paper. Finally, the problems of lignin catalytic conversion existing currently are investigated, and the future development of this field is also prospected.

Structural transformation between rutile and spinel crystal lattices in Ru-Co binary oxide nanotubes: enhanced electron transfer kinetics for the oxygen evolution reaction

A variety of binary Ru-Co mixed oxide nanotubes (Ru_xCo_1-xO_y with x = 0.19, 0.33, 0.47, 0.64 and 0.77) were readily synthesized via electrospinning and subsequent calcination. Ru_xCo_1-xO_y nanotubes (0 < x < 0.77) were composed of both rutile (Ru in RuO₂ is replaced with Co) and spinel (Co in Co₃O₄ is replaced with Ru) structures. This elemental substitution created oxygen vacancies in the rutile structure and also resulted in the incorporation of Ru³⁺ in the octahedral sites of the spinel structure. The as-prepared Ru_xCo_1-xO_y nanotubes were investigated for oxygen evolution reaction (OER) electrocatalytic activity in 1.0 M HClO₄ aqueous solution. Ru_xCo_1-xO_y nanotubes with x≥ 0.47 presented an excellent OER activity comparable to pure RuO₂, known to be the best OER catalyst. Even after more than half of the noble/active Ru content was replaced with cheap/less-active Co, Ru_0.47Co_0.53O_y showed a good OER activity and a greatly improved stability compared to RuO₂ under the continuous OER. These attractive catalytic properties of Ru_xCo_1-xO_y can be attributed to the relatively large surface area of the tubular morphology and the substituted structures, presenting feasibility as a practical and economical OER catalyst.

Earth-abundant 3d-transition-metal catalysts for lignocellulosic biomass conversion

Transformation of biomass to chemicals and fuels is a long-term goal in both science and industry. However, high cost is one of the major obstacles to the industrialization of this sustainable technology. Thus, developing catalysts with high activity and low-cost is of great importance for biomass conversion. The last two decades have witnessed the increasing achievement of the use of earth-abundant 3d-transition-metals in catalysis due to their low-cost, high efficiency and excellent stability. Here, we aim to review the fast development and recent advances of 3d-metal-based catalysts including Cu, Fe, Co, Ni and Mn in lignocellulosic biomass conversion. Moreover, present research trends and invigorating perspectives on future development are given.

Fabrication of Anisotropic Cu Ferrite-Polymer Core-Shell Nanoparticles for Photodynamic Ablation of Cervical Cancer Cells

In this work we developed methylene blue-immobilized copper-iron nanoparticles (MB-CuFe NPs) through a facile one-step hydrothermal reaction to achieve a better phototherapeutic effect. The Fe/Cu ratio of the CuFe NPs was controllable by merely changing the loading amount of iron precursor concentration. The CuFe NPs could serve as a Fenton catalyst to convert hydrogen peroxide (H2O2) into reactive oxygen species (ROS), while the superparamagnetic properties also suggest magnetic resonance imaging (MRI) potential. Furthermore, the Food and Drug Administration (FDA)-approved MB photosensitizer could strongly adsorb onto the surface of CuFe NPs to facilitate the drug delivery into cells and improve the photodynamic therapy at 660 nm via significant generation of singlet oxygen species, leading to enhanced cancer cell-damaging efficacy. An MTT (thiazolyl blue tetrazolium bromide) assay proved the low cytotoxicity of the CuFe NPs to cervical cancer cells (HeLa cells), namely above 80% at 25 ppm of the sample dose. A slight dissolution of Cu and Fe ions from the CuFe NPs in an acidic environment was obtained, providing direct evidence for CuFe NPs being degradable without the risk of long-term retention in the body. Moreover, the tremendous photo-to-thermal conversion of CuFe NPs was examined, which might be combined with photodynamic therapy (PDT) for promising development in the depletion of cancer cells after a single pulse of deep-red light irradiation at high laser power.

Boosting the electrocatalysis of nitrate to nitrogen with iron nanoparticles embedded in carbon microspheres

Human activities have increased the global nitrogen cycle imbalance, leading to serious water pollution. Inexpensive iron nanoparticles with large surface areas are in high demand in the field of environment restoration. Here, we report a hydrothermal method for the preparation of iron-carbon composites (Fe@C) with iron nanoparticles embedded in carbon microspheres. The resulting Fe@C catalyst shows a high nitrate conversion to nitrogen of 75.9% and a nitrogen selectivity of 98%. This study not only provides a simple strategy for the preparation of iron-carbon composites, but also boosts the practical application of Fe@C catalysts for water treatment.

Efficient Synthesis of Sugar Alcohols under Mild Conditions Using a Novel Sugar-Selective Hydrogenation Catalyst Based on Ruthenium Valence Regulation

Sugar alcohols are the prominent alternatives of sugars in food, medical, and health industries. The ruthenium supported on multiwalled carbon nanotubes (Ru/MWCNTs) catalysts were prepared based on the Ru valence regulation strategy and applied for selective sugar hydrogenation to prepare various sugar alcohols including xylitol, arabinitol, sorbitol, mannitol, and galactitol for the first time, with high selectivity (>99.0%) and yield (>98.0%) under mild conditions (≤110 °C, 3.0 MPa H₂ pressure). The hydrogenation reaction of xylose was further optimized and under mild conditions (100 °C, 3.0 MPa H₂ pressure, and 500 rpm), which were lower than ever reported for high efficient synthesis of xylitol, 99.8% xylose conversion and 99.0% xylitol yield were achieved after 120 min of reaction.

Development of coinage metal nanoclusters as antimicrobials to combat bacterial infections

Infections from antibiotic-resistant bacteria have caused huge economic loss and numerous deaths over the past decades. Researchers are exploring multiple strategies to combat these bacterial infections. Metal nanomaterials have been explored as therapeutics against these infections owing to their relatively low toxicity, broad-spectrum activity, and low bacterial resistance development. Some coinage metal nanoclusters, such as gold, silver, and copper nanoclusters, can be readily synthesized. These nanoclusters can feature multiple useful properties, including ultra-small size, high catalytic activity, unique photoluminescent properties, and photothermal effect. Coinage metal nanoclusters have been investigated as antimicrobials, but more research is required to tap their full potential. In this review, we discuss multiple advantages and the prospect of using gold/silver/copper nanoclusters as antimicrobials.

Metal-Catalyzed Hydrogenation of Biomass-Derived Furfural: Particle Size Effects and Regulation Strategies

The hydrogenation of furfural (FUR), a typical bio-based furan derivative, is a critical reaction within the roadmap for upgrading lignocellulosic biomass into high value-added chemicals and liquid fuels, the performance of which is strongly correlated with the catalysts' intrinsic peculiarities. Metal catalysts with tailorable sizes, uniform dispersions and robust sintering resistance are generally recognized as a prerequisite for obtaining better hydrogenation activity, selectivity and stability, which has prompted intensive research into metal particle size effects and their regulation strategies. The roles of metal particle sizes and corresponding dispersions of metal catalysts used for FUR hydrogenation have been clearly recognized to be crucial over the past decade. In this regard, this systematic Minireview aims to provide profound insights into particle size effects in the metal-catalyzed hydrogenation of FUR, as well as conditional and structural approaches to regulating these effects. In addition, from the aspect of catalyst stability, the impacts and improvements of the metal particle sintering issue are analyzed. Moreover, several suggestions are proposed in response to the challenges in regulating particle size effects. Furthermore, the viewpoints presented herein would potentially contribute to the rational development of metal hydrogenation catalysts and further help to boost a more sustainable biomass refining system.

Size Effect in Pd-Ir Core-Shell Nanoparticles as Nanozymes

Comprehensive studies on the size effect in nanozyme (i. e., nanomaterials with enzyme-like activities)-based catalysis have rarely been reported. In this work, we systematically investigated the size effect in nanozymes by using Pd-Ir core-shell nanoparticles with peroxidase-like activities as a model system. Pd-Ir nanoparticles with four different sizes (3.3, 5.9, 9.8 and 13.0 nm), but identical shapes and surface structures, were designed and synthesized. We found that the catalytic activity for individual nanozymes increased with particle size. The area-specific catalytic activity was similar for nanoparticles of 3.3-9.8 nm, but decreased slightly when particle size reached 13.0 nm. By using an enzyme-linked immunosorbent assay (ELISA) as a model platform, the size effect of Pd-Ir nanoparticles in biosensing applications was investigated; smaller nanoparticles were found to offer lower detection limits. This work not only demonstrates the size effect, but also provides an effective strategy to enhance the performance of nanozymes in certain applications.

Development of biochar-based nanocatalysts for tar cracking/reforming during biomass pyrolysis and gasification

Gasification and pyrolysis have been considered as potential routes for the production of fuel gas from abundant, low-cost and renewable biomass materials. Tar is the undesirable but inevitable byproduct during these processes, which not only lowers the overall energy conversion efficiency but also leads to potential contamination and clogging problems. Catalytic reforming has been seen as one of the most promising methods for tar elimination, and biochar-based nanocatalysts (BBNs) show promise as an efficient tar reforming catalyst. Extensive research efforts have been devoted to the development of BBNs to reduce biomass tar below tolerable limits. This current study reviews the recent progress in the preparation and application of BBNs for converting tar into fuel gas during biomass gasification or pyrolysis. The formation and chemical characteristics of the BBNs are introduced for a better understanding of the catalytic mechanism; prospects for success, as well as challenges, are also discussed.

Electrochemical Conversion of the Lignin Model Veratryl Alcohol to Veratryl Aldehyde Using Manganese(III)-Schiff Base Homogeneous Catalysts

Lignin and other colored structures need to be bleached after the Kraft process in the pulp industry. Development of environmentally-safe bleaching catalysts or electrocatalysts constitutes an attractive strategy for selective removal of lignin. Seven manganese(III)-complexes with Schiff base ligands 1–7 were synthetized and characterized by different analytical and spectroscopic techniques. The tetragonally elongated octahedral geometry for the manganese coordination sphere and the global µ-aquo dimeric structure were revealed by X-ray diffraction (XRD) studies for 1, Mn2L12(H2O)2(N(CN)2)2 (N(CN)2 = dicyanamide). Complexes 1–4 behave as more efficient peroxidase mimics as compared to 5–7. Electrochemical oxidation of the lignin model veratrylalcohol (VA) to veratrylaldehyde (VAH) is efficiently catalyzed by a type of dimanganese(III) complexes in a chlorine-free medium. The electrocatalytic reaction proceeds through the oxidation of chloride into hypochlorite at alkaline pH along with the formation of hydrogen from water as a subproduct.

Antimicrobial Gold Nanoclusters: Recent Developments and Future Perspectives

Bacterial infections have caused serious threats to public health due to the antimicrobial resistance in bacteria. Recently, gold nanoclusters (AuNCs) have been extensively investigated for biomedical applications because of their superior structural and optical properties. Great efforts have demonstrated that AuNCs conjugated with various surface ligands are promising antimicrobial agents owing to their high biocompatibility, polyvalent effect, easy modification and photothermal stability. In this review, we have highlighted the recent achievements for the utilizations of AuNCs as the antimicrobial agents. We have classified the antimicrobial AuNCs by their surface ligands including small molecules (< 900 Daltons) and macromolecules (> 900 Daltons). Moreover, the antimicrobial activities and mechanisms of AuNCs have been introduced into two main categories of small molecules and macromolecules, respectively. In accordance with the advancements of antimicrobial AuNCs, we further provided conclusions of current challenges and recommendations of future perspectives of antimicrobial AuNCs for fundamental researches and clinical applications.

Preparation and Properties of Jute Fiber Long-Chain Fatty Acid Esters in Supercritical Carbon Dioxide

A two-step method involving continuous screw-extrusion steam explosion (CSESE) pretreatment and esterification in supercritical carbon dioxide (scCO₂) is used to prepare long-chain fatty acid-modified jute fiber. The weight gain percentage (WG %) of CSESE-pretreated jute laurate (JL) was 110.7% when esterification was carried out in scCO₂ at 14 MPa and 100 °C for 2 h. The corresponding WG % was 105.5% when esterification was instead carried out in pyridine at 100 °C for 2 h. Scanning electron microscopy and X-ray diffraction indicated that CSESE pretreatment enhanced the reactivity of jute fiber, with esterification in scCO₂ simultaneously occurring on the fibers surface and internal walls. The glass transition temperature of esterified jute was approximately 119 °C, indicating that it could be hot processed over a wide temperature range. The esterified jute had an oil absorption ratio of 17.01 g/g, so it can be used as an oil absorption material.

Leather-Promoted Transformation of Glucose into 5-Hydroxymethylfurfural and Levoglucosenone

The search for efficient catalysts frequently leads to new homogeneous and heterogeneous catalysts of increasing complexity, and sometimes common, natural, or hybrid natural/synthetic materials that could be used in catalysis are overlooked. For example, the leather industry has produced robust Cr-containing materials for centuries by chemical treatment of animal hides with chromium salts. Herein, the use of chromium-tanned leather as a heterogeneous catalyst for glucose dehydration to 5-hydroxymethylfurfural (5-HMF) and levoglucosenone (LGO) is reported. Four pieces of waste leather were obtained from shoe soles and a belt, characterized by a range of techniques including FTIR spectroscopy, SEM, BET surface area measurements, XRD, and X-ray photoelectron spectroscopy, and their catalytic activity was evaluated. The activity of the scrap leather pieces compares favorably to those of many recently reported catalysts for the preparation of 5-HMF, but additionally results in significant quantities of LGO. Overall, the results demonstrate that waste leather is an outstanding material for use in catalysis.

Advances in porous and nanoscale catalysts for viable biomass conversion

Solid catalysts with unique porosity and nanoscale properties play a promising role for efficient valorization of biomass into sustainable advanced fuels and chemicals.

A perovskite oxide with a tunable pore-size derived from a general salt-template strategy as a highly efficient electrocatalyst for the oxygen evolution reaction

A porous perovskite oxide is fabricated by an inorganic salt-template strategy, which exhibits remarkable performance for the oxygen evolution reaction.

Quaternized POSS modified rGO-supported Pd nanoparticles as a highly efficient catalyst for reduction and Suzuki coupling reactions

Hydrophilic QPOSS modified rGO nanosheets are fabricated as a robust catalyst support of PdNPs for reduction and Suzuki coupling reactions.

Directed evolution of the optoelectronic properties of synthetic nanomaterials

We present the use of directed evolution for the engineering of the optoelectronic properties of DNA-wrapped single-walled carbon nanotubes (DNA-SWCNTs).

The Use of a Molybdenum Polyoxometalated Compound to Increase the Amount of Extractives from Wood Wastes

The treatment of wood wastes of Castanea sativa L., Quercus frainetto, Larix decidua, and Paulownia tomentosa S. in autoclave in the presence of micrometric crystals of H₃PMo12O40 showed an impressive increase of the amount of extractives. The extractives were mainly constituted of insoluble compounds that were analyzed by using gas chromatography-mass spectrometry (GC-MS) after acetylation. The GC-MS analysis of the chloroform soluble fraction of the extractives obtained from sativa showed the presence of methyl hexadecanoate and octadecanoic acid, that of the extractives of frainetto showed the presence of octadecanal and some long chain hydrocarbons. decidua extracts showed the presence of large amounts of sesamin, while the extractives of P tomentosa revealed the presence of 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxycimmanaldehyde, and relevant amounts of long chain hydrocarbons. The insoluble fraction showed the presence of relevant amounts of several carbohydrates and, in the case of C. sativa, of inositol.

Construction of Bifunctional Co/H-ZSM-5 Catalysts for the Hydrodeoxygenation of Stearic Acid to Diesel-Range Alkanes

Bifunctional Co/H-ZSM-5 zeolites were prepared by a surface organometallic chemistry grafting route, namely, by the stoichiometric reaction between cobaltocene and the Brønsted acid sites in zeolites. The catalyst was applied to a model reaction of the catalytic hydrodeoxygenation of stearic acid (SA). The cobalt species existed in the form of isolated Co²⁺ ions at the exchange positions after grafting, transformed to CoO species on the surface of the zeolite, stabilized inside the zeolite channels upon calcination in air, and finally reduced by hydrogen to homogeneous clusters of metallic cobalt species approximately 1.5 nm in size. During this process, the Brønsted acid sites of the H-ZSM-5 zeolites were preserved with a slightly reduced acid strength. The as-prepared bifunctional catalyst exhibited an approximately 16 times higher activity for the hydrodeoxygenation of SA (2.11 g_SA  g_cat^-1  h^-1 ) than the reference catalyst (0.13 g_SA  g_cat^-1  h^-1 ) prepared by solid-state ion exchange and a high C₁₈ /C₁₇ ratio of approximately 24. The remarkable hydrodeoxygenation performance of the bifunctional Co/H-ZSM-5 was owed to the effective synergy between the uniformed metallic cobalt clusters and the Brønsted acid sites in H-ZSM-5. The simplified reaction network and kinetics of the SA hydrodeoxygenation catalyzed by the as-prepared bifunctional Co/H-ZSM-5 zeolites were also investigated.