Many studies have examined metallic nanoparticles (NPs) produced according to the principles of green chemistry. Gold NPs have drawn much more attention than other metallic NPs in recent years. Moreover, among all gold NP synthesis studies, using plant-derived molecules is one of the commonly used reductants in studies on NP synthesis because of its convenience in terms of shape, size control advantage, and nontoxic specifications. The present review focused on studies of the synthesis of gold NP types, including single gold atom NPs, alloyed AU NPs, and core-shell Au NPs as well as their conditions and applications. The effect of those structures on application fields such as catalysis, antifungal action, antibacterial activities, sensors and so on are also summarized. Furthermore, the morphology and synthesis conditions of the primer and secondary NP were discussed. In addition to synthesis methods, characterization methods were analyzed in the context of the considerable diversity of the reducing agents used. As the reducing agents used in most studies, polyphenols and proteins usually play an active role. Finally, the challenges and drawbacks in plant-derived agent usage for the preparation of Au NPs at various industries were also discussed.
Porous carbon materials attract great interest because of the wide range of applications in electrochemical energy systems, especially in the case of structured and porosity-tuned carbons prepared by template-assisted methods. The use of surfactant prevents the collapse of the porous structure during the air-drying stage in the sol-gel process, which is regarded as a critical stage in this method. This work offers an overview on the use of surfactants as templates for the manufacture of tunable porous carbon materials by the sol-gel method mainly using the polymerization reaction of resorcinol (R) and formaldehyde (F). The use of surfactants avoids the application of other economically disadvantaged drying techniques such as supercritical fluids and freeze-drying. The surfactant-assisted sol-gel methods reported in the literature for the fabrication of porous carbons are widely discussed, as well as the potentiality of the synthesized materials as electrodes in electrochemical systems, which greatly depends on the final porous structure. Besides, this work offers information on hybrid methods in which surfactants are used not only for the fabrication of porous carbon materials with mesoporous/microporous structure but also for the development of advanced structures and composites, including nanomaterials with enhanced properties. Finally, future prospects in the synthesis of carbon materials prepared by surfactant-assisted sol-gel method are presented.