Among 50 strains of Pseudomonas aeruginosa tested for the resistance to antibiotics, strain ryn32 was selected for this study based on its resistance level. It showed complete resistance toward aztreonam and almost complete resistance (96%) against kanamycin. Iron nanoparticles (FeNPs) were then prepared and found with diameters 30-50 nm. The threshold level of FeNPs for pyoverdines (PVDs) production by P. aeruginosa ryn32 was found at 25 μM concentration. PVDs production was optimal with pH 7.5, 35 C, succinate as carbon source, ammonium sulfate as nitrogen source at 60 hr fermentation time. Interestingly, when used the PVDs as conjugates with FeNPs they showed antibacterial action against the producing strain and some other gram-negative bacteria. This suggests that the conjugates enter the bacterial cell via the ferriPVDs uptake pathway, which triggers the accumulation of FeNPs inside the cell, which is crucial on bacterial viability. Growth stimulation with the same concentrations of FeNPs and PVDs in separate treatments supported this view. K E Y W O R D S antimicrobials, iron nanoparticles, Pseudomonas aeruginosa, pyoverdine, siderophore 1 | INTRODUCTION Pseudomonas aeruginosa is one of the most known bacterial pathogens in human history. As an inhabitant of soil, it is frequently found in air from which it may gain access to humans and animals. It is well established as a potential opportunistic pathogen, especially in hospitals. The problem is much complicated by their resistance to most antibiotics and many disinfectants with the subsequent emergence of new resistant strains. 1 The treatment of these resistant strains becomes a challenge. The resistance of P. aeruginosa may due to the presence of alginate biofilm, the low permeability of the outer membrane, the active export of low molecular weight drugs and the production of β-lactamases. 2The pathogenicity of P. aeruginosa is linked with its ability to produce siderophores to attain Fe 3+ ions from the human body. 3 Iron is the most required trace element in the metabolism of bacteria making it a crucial basis of environmental struggle. To manage irondeficient conditions, bacteria secrete siderophores into the environment. These low molecular mass (usually lower than 2 kD) molecules chelate the insoluble iron present in the surrounding. Iron is then set free by the metallo-reductases at the periplasmic space and be taken up via siderophore receptors located on the bacterial cell membrane. 4

Design of solid‐supported metal catalysts (SSMCs) has made an increasingly important contribution to heterogeneous catalysis in terms of fundamental understanding and technological applications. For instance, industrial use of supported catalysts for oxidation, reduction, and C−C bond formation reactions is highly prevalent. The reason behind this is that such catalysts are economical, have high thermal stability, dispersion, high exposed surface area, and above all, high reusability (up to multiple subsequent cycles). Such characteristics make supported catalysts ideal for green synthesis. However, unlike homogeneous catalysis, heterogeneous catalysis is widely applied in crude oil refining, the pharmaceutical industry, water purification, natural product synthesis, and environmental catalysis. Carbon‐carbon bond formation reactions are frequently used in the organic synthesis using SSMCs. SSMCs are attractive to synthetic chemists due to their easy recovery and excellent stability compared to unsupported metal catalysts. However, the major drawback of SSMCs is related to metal sintering at elevated temperatures caused by weak interactions between the metal and solid support in SSMCs. This review highlights major advancements in SSMCs. Three commonly reported solid supports for metal catalysts, such metal oxides, carbonaceous materials, and polymeric compounds, are discussed. Moreover, a series of thermo‐ and photocatalyzed reactions, such as hydrogenation, carbon‐carbon bond formation, oxidation reactions and multicomponent reactions and the effect of variable supports towards activity and selectivity are demonstrated.

Enhancing gas sensor efficiency: DFT explores the potential of carbene-functionalized graphene.

A catalytic system for selective transformation of furfural into biofuel is highly desirable. However, selective hydrogenation of the C=O group over the furan ring of furfural to produce ether in one step is challenging. Here, we report the preparation of a series of magnetically recoverable FeCo@GC nano‐alloys (37–40 nm). Fe3O4 (3–5 nm) and MOF‐71 (Co), used as the Co and C source, were mixed together in a range of Fe/Co ratios, and then encapsulated in a graphitic carbon (GC) shell to prepare such alloys. STEM‐HAADF shows the darker core made of FeCo and the shell of graphitic carbon. Furfural is hydrogenated to produce >99% isopropyl furfuryl ether in isopropanol with >99% conversion at 170 °C under 40 bars of H2, whereas n‐chain alcohol, such as ethanol, produces corresponding ethyl levulinate in 93%. The synergistic effect due to the charge transfer from Fe to Co leads to higher reactivity of FeCo@GC. The catalyst, which can be separated from the reaction medium using a simple magnet without significant damage to the surface or composition, retained its reactivity and selectivity for up to four consecutive cycles.

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Correction for ‘Surface modification of graphene with functionalized carbenes and their applications in the sensing of toxic gases: a DFT study’ by Sarah Aldulaijan et al., RSC Adv., 2023, 13, 19607–19616, https://doi.org/10.1039/D3RA02557H.