Cu-ZnO@Al2O3 hybrid nanoparticle with enhanced activity for catalytic CO2 conversion to methanol

Sustainable methanol production from carbon dioxide: advances, challenges, and future prospects

The urgent need to address global carbon emissions and promote sustainable energy solutions has led to a growing interest in carbon dioxide (CO2) conversion technologies. Among these, the transformation of CO2 into methanol (MeOH) has gained prominence as an effective mitigation strategy. This review paper provides a comprehensive exploration of recent advances and applications in the direct utilization of CO2 for the synthesis of MeOH, encompassing various aspects from catalysts to market analysis, environmental impact, and future prospects. We begin by introducing the current state of CO2 mitigation strategies, highlighting the significance of carbon recycling through MeOH production. The paper delves into the chemistry and technology behind the conversion of CO2 into MeOH, encompassing key themes such as feedstock selection, material and energy supply, and the various conversion processes, including chemical, electrochemical, photochemical, and photoelectrochemical pathways. An in-depth analysis of heterogeneous and homogeneous catalysts for MeOH synthesis is provided, shedding light on the advantages and drawbacks of each. Furthermore, we explore diverse routes for CO2 hydrogenation into MeOH, emphasizing the technological advances and production processes associated with this sustainable transformation. As MeOH holds a pivotal role in a wide range of chemical applications and emerges as a promising transportation fuel, the paper explores its various chemical uses, transportation, storage, and distribution, as well as the evolving MeOH market. The environmental and energy implications of CO2 conversion to MeOH are discussed, including a thermodynamic analysis of the process and cost and energy evaluations for large-scale catalytic hydrogenation.

Design of Aerosol Nanoparticles for Interfacial Catalysis

Interest in multifunctional nanoparticles is currently rising due to the increasing demand in green energy and environmental applications. The aerosol-based synthetic route emerges as a promising method for enabling the fabrication of multifunctional nanoparticles in a continuous and scalable manner. Meanwhile, interfacial catalysis is receiving great attention to enhance the performance of chemical reactions. In this regard, the utilization of aerosol nanoparticles is highly beneficial to the catalysis field by the creation of strong metal-support-promoter interactions for promoting interfacial catalysis. In this Perspective, aerosol-based synthesis of hybrid nanoparticles is briefly discussed. In addition, the interfacial catalysis of CO oxidation, methane combustion, CO₂ hydrogenation, and dry reforming of methane are discussed to provide fundamental insights and concepts for the rational design of nanocatalysts with efficient interfaces.

Conversion of Plastic Waste into Supports for Nanostructured Heterogeneous Catalysts: Application in Environmental Remediation

Plastics are ubiquitous in our society and are used in many industries, such as packaging, electronics, the automotive industry, and medical and health sectors, and plastic waste is among the types of waste of higher environmental concern. The increase in the amount of plastic waste produced daily has increased environmental problems, such as pollution by micro-plastics, contamination of the food chain, biodiversity degradation and economic losses. The selective and efficient conversion of plastic waste for applications in environmental remediation, such as by obtaining composites, is a strategy of the scientific community for the recovery of plastic waste. The development of polymeric supports for efficient, sustainable, and low-cost heterogeneous catalysts for the treatment of organic/inorganic contaminants is highly desirable yet still a great challenge; this will be the main focus of this work. Common commercial polymers, like polystyrene, polypropylene, polyethylene therephthalate, polyethylene and polyvinyl chloride, are addressed herein, as are their main physicochemical properties, such as molecular mass, degree of crystallinity and others. Additionally, we discuss the environmental and health risks of plastic debris and the main recycling technologies as well as their issues and environmental impact. The use of nanomaterials raises concerns about toxicity and reinforces the need to apply supports; this means that the recycling of plastics in this way may tackle two issues. Finally, we dissert about the advances in turning plastic waste into support for nanocatalysts for environmental remediation, mainly metal and metal oxide nanoparticles.

Construction of AuNPs/Cu,I-CD-based colorimetric sensor: Catalytic oxidation of TBHQ and the catalytic inhibition of HCHO

Various research groups have been paying huge attention to tune the metal states in metal-carbon hybrid materials. Herein, a mixed-valence copper-iodine co-doped carbon dots (Cu,I-CDs, Cu²⁺/Cu⁺/Cu⁰) were prepared through a one-step hydrothermal method, which displayed an intrinsic reduction performance under given conditions. Moreover, AuNPs/Cu,I-CDs composite was fabricated using Cu,I-CDs as reductant and stabilizer. Among them, the AuNPs/Cu,I-CDs composite exhibited the highest oxidase- and peroxidase-like activities, which was used for the colorimetric detection of tert-butyl hydroquinone (TBHQ), with the detection limits of 23.45 μg/kg. Interestingly, the catalytic oxidation of TBHQ to oxidized TBHQ (TQ) could be inhibited by formaldehyde (HCHO). Therefore, a colorimetric sensor for HCHO was developed with the detection limit 0.335 mg/L. The catalytic mechanism for TBHQ was investigated by employing scavengers of different reactive species, indicating the significant roles of •O₂^- in the catalytic process. Therefore, it is believed that the as-prepared AuNPs/Cu,I-CDs nanozyme has promising potential applications in the fields of biomedicine and food safety.

New insight into the mechanism of carbon dioxide activation on copper-based catalysts: A theoretical study

A combination of Artificial Bee Colony algorithm, eXtended Tight Binding and Density functional theory methods were performed to study the activation process of carbon dioxide (CO₂) over copper (Cu₄ cluster) based catalytic systems. The findings revealed that the activation of the C-O bond resulted from the electron transfer to σ*, π* - MO of CO₂. The more the electrons are transferred to CO₂, the more the C-O bond is activated and elongated. The suitability of several metal oxide supports (Fe₂O₃, Al₂O₃, MgO, ZnO) is estimated using calculated electronic parameters (global electrophilicity index, vertical ionization potential and vertical electron affinity). Aside from demonstrating the appropriateness of Al₂O₃ and ZnO, a thorough examination of MgO revealed that, due to the formation of stable carbonate products, this oxide is not really appropriate as a support for copper-based catalysts in CO₂ conversion. Our studies have also shown that the electron enrichment of copper atoms plays a key role in the activation of C-O bonds. Alkali metal doping (Li, K, Cs) significantly improves the catalytic efficiency of the Cu₄ cluster. Based on the results of electron transfer to the CO₂ molecule, the effect of doping alkali metal atoms may be organized in the following order: Cs > K > Li. A new core/shell catalytic system with potassium atoms in the core and copper atoms in the shell has been proposed and has proven to be a promising, efficient catalytic system in the CO₂ adsorption and activation.