Modification of ZnCoPBA by different organic ligands and its application in the cycloaddition of CO2 and epoxides

Research progress on the synthesis, performance regulation, and applications of Prussian blue nanozymes

Nanocatalytic medicine offers a novel solution to address the issues of low efficacy, potential side effects, and the development of drug resistance associated with traditional therapies. Therefore, developing highly efficient and durable nanozymes is of great significance for treating diseases related to oxidative stress. In recent years, prussian blue nanoparticles (PBNPs) have been demonstrated to possess multiple enzyme-like catalytic activities and are thus referred to as prussian blue nanozymes (PBNZs). Their excellent biocompatibility and biodegradability make PBNZs promising candidates as biomedical materials. Due to their remarkable catalytic activities, PBNZs have shown great potential in various biomedical applications, such as heavy metal detoxification, antioxidative damage, and anticancer therapies. This paper systematically summarizes the Synthetic strategies of PBNZs, analyzes the regulatory factors of their catalytic performance, and highlights the corresponding modulation methods. Furthermore, the biomedical applications of PBNZs are also reviewed. This study aims to provide researchers with insights and inspirations for the design and preparation of high-performance PBNZs.

Synthesis, Structure, and Actual Applications of Double Metal Cyanide Catalysts

Double metal cyanide (DMC) complexes represent a unique family of materials with an open framework structure. The main current application of these complexes in chemical industry is their use as catalysts (DMCCs) of the ring-opening polymerization of propylene oxide (PO), yielding branched polyols, highly demanded in production of polyurethanes and surfactants. The actual problem of chemical fixing carbon dioxide from the atmosphere gave new impetus to the development of DMCCs, which turned out to be effective in oxirane/CO2 copolymerization. In recent years, new types and formulations of DMCCs were created, so that greater understanding of the reaction mechanisms was achieved and new fields of catalytic applications were found. In the present review, we summarized background and actual information about the synthesis, structure, and mechanisms of the action of DMCCs, as well as their application in the development of new materials and fine chemicals.

Unraveling the role of internal-external metal substitution in Zn3[Co(CN6)]2 for the styrene oxide-CO2 cycloaddition reaction

We investigated the influence of the structural and textural properties along with the chemical environment of pure Zn3[Co(CN)6]2 in comparison with the modified phases on the catalytic performance in the cycloaddition reaction between styrene oxide and CO2. We relate these to the proposed reaction pathways and mechanisms. The natural cubic phase (ZnCoCn) was dehydrated to obtain the rhombohedral phase (ZnCoRn), while the stabilized cubic phase (ZnCoCs) was synthesized by substituting external zinc atoms with cadmium atoms. The rhombohedral stabilized phase (ZnCoRs) was achieved by the internal cobalt change with iron. All the materials were extensively characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and N2 adsorption. The catalytic behavior of the four phases was tested. The crystalline structure of each phase was obtained, and by XPS, it was demonstrated that the chemical environments of all elements conforming to the rhombohedral stabilized phase are different from those of all other materials owing to the exchange of internal metals. The bulk textural properties were similar; only the ZnCoRs presented more micropore area but did not exceed the total surface area of the other materials. The product distribution and yield at reaction times of 2 h and 6 h were closer to those of the cubic phases. The natural rhombohedral phase exhibits the best performance. The tetrabutylammonium bromide (TBAB) and rhombohedral stabilized phase work together to yield a bigger copolymer quantity at the expense of the styrene carbonate (StCO3) production. From the proposed mechanism, the TBAB cation (TBA+) has a "protection" function that drives the closing of the StCO3 ring; however, the charge distribution anisotropy in the four nitrogen atoms generated by Co replacement in ZnCoRs could hold TBA+ as the reaction time progressed, causing an unavailability that triggered the copolymerization propagation step.

Enhanced catalytic reduction of p-nitrophenol and azo dyes on copper hexacyanoferrate nanospheres decorated copper foams

Catalytic reduction of nitroaromatic compounds using low-cost non-precious metal containing catalyst remains an essential topic in wastewater treatment. Herein, copper hexacyanoferrate nanospheres decorated copper foams (CF) were prepared by a facile method, and it was used as structured catalysts for the reduction of p-nitrophenol (p-NP) and azo dyes. The catalyst obtained by calcination at 200 °C shows the highest catalytic activity, with an almost complete reduction of p-NP within 3 min with a rate of 2.057 min^-1 at room temperature, and it exhibited excellent reusability in successive 6 cycles. The effects of temperature, initial concentration, pH, and flow rate on p-NP reduction were investigated. Moreover, the mechanistic investigation revealed that fast electron transfer ability and enhanced adsorption for p-NP contributed to its enhanced catalytic performances. This work put forward an efficient approach for the construction of structured catalysts with enhanced performance in catalytic reduction applications.