This study reveals the effect of the catalytic 1D supports (carbon, ceria, alumina and titanate) for ruthenium particles on the low temperature release of hydrogen from ammonia. While the state-of-art literature presents Ru/carbon nanotubes (CNT) as the most active catalyst, we found in this work that ruthenium supported on ceria nanorods (Ru/CeO₂) catalyst exhibited activity over 8 times higher than the Ru/CNT counterpart system. This enhanced activity is believed to be related to a strong metal-support interaction on the Ru/CeO₂ catalysts promoting the formation of small (~ 3 nm) Ru particles. Addition of sodium as a promoter leads to the formation of smaller Ru particle sizes in addition to the modification of the electronic environment of Ru, enhancing the ammonia decomposition activity at low temperatures. This effect is particularly noticeable in the Ru–Na/CNT catalysts, facilitated by the high conductivity of the support, allowing distant electronic modification of the Ru active sites. This work provides novel insights in designing catalysts for hydrogen production from ammonia in our effort to enable the long-term energy storage in chemical bonds.

Functionalized iron oxide nanoparticles are of great interest for multiple biomedical applications. However, it remains a considerable challenge to manufacture these nanoparticles reproducibly on a large scale with the appropriate surface coating to render them completely stable and biocompatible. To overcome this problem, a novel combination of synthesis and functionalization using modular microreactor systems is presented here, avoiding the need of intermediate ligand exchange steps. Continuous flow technology enables reproducible synthesis of bare iron oxide nanoparticles (7 ± 2 nm) in water under mild conditions, in tandem with extremely fast and efficient functionalization with a custom heterobifunctional PEG stabilizer. The nanoparticles can be easily derivatized with any molecule of interest through simple amide coupling, demonstrating their capacity to act as a versatile platform for biomedical applications. The produced iron oxide nanoparticles are fully biocompatible based on a LDH cytotoxicity assay, highly stable in various biologically relevant media and suitable for T₂ MRI contrast applications (r₁ = 1.44 mM⁻¹ s⁻¹, r₂ = 272 mM⁻¹ s⁻¹). A full cost analysis reveals the commercial viability of the process, with a total cost as low as £ 506 g⁻¹, demonstrating the potential of this modular approach to enable the large-scale deployment of functionalized nanomaterials in real world applications.

Electronic systems and telecommunication devices based on low-power microwaves, ranging from 2 to 40 GHz, have massively developed in the last decades. Their extensive use has contributed to the emergence of diverse electromagnetic interference (EMI) phenomena. Consequently, EMI shielding has become a ubiquitous necessity and, in certain countries, a legal requirement. Broadband absorption is considered the only convincing EMI shielding solution when the complete disappearance of the unwanted microwave is required. In this study, a new type of microwave absorber materials (MAMs) based on reduced graphene oxide (rGO) decorated with zero-valent Fe@γ-Fe₂O₃ and Fe/Co/Ni carbon-protected alloy nanoparticles (NPs) were synthesized using the Pechini sol-gel method. Synthetic parameters were varied to determine their influence on the deposited NPs size and spatial distribution. The deposited superparamagnetic nanoparticles were found to induce a ferromagnetic resonance (FMR) absorption process in all cases. Furthermore, a direct relationship between the nanocomposites’ natural FMR frequency and their composition-dependent saturation magnetization (M_s) was established. Finally, the microwave absorption efficiency (0.4 MHz to 20 GHz) of these new materials was found to range from 60% to 100%, depending on the nature of the metallic particles grafted onto rGO.