Journal of Molecular and Engineering Materials

Catalysis, as the key to minimize the energy requirement and environmental impact of today's chemical industry, plays a vital role in many fields directly related to our daily life and economy, including energy generation, environment control, manufacture of chemicals, medicine synthesis, etc. Rational design and fabrication of highly efficient catalysts have become the ultimate goal of today's catalysis research. For the purpose of handling and product separation, heterogeneous catalysts are highly preferred for industrial applications and a large part of which are the composites of transition metal nanoparticles (TMNPs). With the fast development of nanoscience and nanotechnology and assisted with theoretical investigations, basic understanding on tailoring the electronic structure of these nanocomposites has been gained, mainly by precise control of the composition, morphology, interfacial structure and electronic states. With the rise of graphene, chemical routes to prepare graphene were developed and various graphene-based composites were fabricated. Transition metal nanoparticles-reduced graphene oxide (TMNPs–rGO) composites have attracted considerable attention, because of their intriguing catalytic performance which have been extensively explored for energy- and environment-related applications to date. This review summarizes our recent experimental and theoretical efforts on understanding the superior catalytic performance of subnanosized TMNPs–rGO composites.

In this paper, organic optoelectronic research activities in the field of benzo[1,2-c;4,5-c′]bis[1,2,5]thiadiazole (BBT)-based materials are reviewed. Synthetic pathways to the BBT core and its computational studies are described. Collective observations from separate reports suggest open-shell biradical nature of BBT-based materials. Future research directions for these materials are also described.

As molecular synthesis advances, we are beginning to learn control of not only the chemical reactivity (and function) of molecules, but also of their interactions with other molecules. It is this basic idea that has led to the current explosion of supramolecular science and engineering. Parallel to this development, chemists have been actively pursuing the design of very large molecules using basic molecular building blocks. Herein, we review the general development of supramolecular chemistry and particularly of two new branches: supramolecular coordination complexes (SCCs) and metal organic frameworks (MOFs). These two fields are discussed in detail with typical examples to illustrate what is now possible and what challenges lie ahead for tomorrow's molecular artisans.

Over the last 50 years, remarkable improvements in mechanical and barrier properties of polymer composites have been realized. Their improved properties have been widely studied and employed for food packaging to keep food fresh, clean and suitable for consumption over sufficiently long storage period. In this paper, the current progress of science and technology development of polymer composites for intelligent food packaging will be highlighted. Future directions and perspectives for exploring polymer composites for intelligent food packaging to reveal freshness and quality of food packaged will also be put forward.

Carbon dioxide (CO₂) is an attractive C1 resource because it is cheap and abundant and its more extensive use would be beneficial for the environment. However, its high thermodynamic stability and poor reactivity have seriously limited its utilization as a ready carbon source. The scientific challenges facing CO₂ transformation are accordingly very attractive. This paper summarizes recent advances made in transformation of CO₂ to value-added high-molecular-weight materials such as polymers, star-shaped molecules and nanocarbons.

Core-shell structured Cu/Cu₂O nanowires were demonstrated as efficient catalysts for C–S cross-coupling reactions. The excellent coupling activity over Cu/Cu₂O nanowires on a diverse set of aryl iodides and thiols is attributed to the synergetic effect of the special core-shell structures and their advanced spatial configuration.

Bifunctional catalyst that is active for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the most important components of rechargeable metal–air batteries. Nanostructured perovskite bifunctional catalysts comprising La, Co and Mn(LaCo_1-xMn_xO₃, LCMO) are synthesized by hydrothermal methods. The morphology, structure and electrochemical activity of the perovskite bifunctional catalysts are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and rotating disk electrode (RDE) techniques. Nanorod, nanodisc and nanoparticle are typical morphologies of LCMO. The electrocatalytic activity of LCMO is significantly improved by the addition of conductive materials such as carbon nanotube. To demonstrate the practical utilization, LCMO in the composition of LaCo_0.8Mn_0.2O₃(LCMO82) is used as air cathode catalysts for rechargeable zinc–air batteries. The battery prototype can sustain 470 h or 40 discharge–charge cycles equivalent.

Topological transformation manifested in inorganic materials shows manifold possibilities. In our present work, we show a clear topological transformation in a soft-oxometalate (SOM) system which was formed from its polyoxometalate (POM) precursor [PMo₁₂@Mo₇₂Fe₃₀]. This topological transformation was observed due to time dependent competitive self-assembly of two different length scale soft-oxometalate moieties formed from this two-component host–guest reaction. We characterized different morphologies by scanning electron microscopy, electron dispersive scattering spectroscopy, dynamic light scattering, horizontal attenuated total reflection–infrared spectroscopy and Raman spectroscopy. The predominant structure is selected by its size in a sort of supramolecular Darwinian competition in this process and is described here.