Oxidized Carbon Black as an Activator of Transesterification Reactions under Solvent-Free Conditions

Nanoporous Crystalline Composite Aerogels with Reduced Graphene Oxide

High-porosity monolithic composite aerogels of syndiotactic polystyrene (sPS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) containing reduced graphene oxide (r-GO) were prepared and characterized. The composite aerogels obtained by supercritical carbon dioxide (scCO₂) extraction of sPS/r-GO and PPO/r-GO gels were characterized by a fibrillar morphology, which ensured good handling properties. The polymer nanoporous crystalline phases obtained within the aerogels led to high surface areas with values up to 440 m² g⁻¹. The role of r-GO in aerogels was studied in terms of catalytic activity by exploring the oxidation capacity of composite PPO and sPS aerogels toward benzyl alcohol in diluted aqueous solutions. The results showed that, unlike sPS/r-GO aerogels, PPO/r-GO aerogels were capable of absorbing benzyl alcohol from the diluted solutions, and that oxidation of c.a. 50% of the sorbed benzyl alcohol molecules into benzoic acid occurred.

Graphene Oxide and Oxidized Carbon Black as Catalyst for Crosslinking of Phenolic Resins

Influence of different graphite-based nanofillers on crosslinking reaction of resorcinol, as induced by hexa(methoxymethyl)melamine, is studied. Curing reactions leading from low molecular mass compounds to crosslinked insoluble networks are studied by indirect methods based on Differential Scanning Calorimetry. Reported results show a catalytic activity of graphene oxide (eGO) on this reaction, comparable to that one already described in the literature for curing of benzoxazine. For instance, for an eGO content of 2 wt %, the exothermic crosslinking DSC peak (upon heating at 10 °C/min) shifted 6 °C. More relevantly, oxidized carbon black (oCB) is much more effective as catalyst of the considered curing reaction. In fact, for an oCB content of 2 wt %, the crosslinking DSC peak can be shifted more than 30 °C and a nearly complete crosslinking is already achieved by thermal treatment at 120 °C. The possible origin of the higher catalytic activity of oCB with respect to eGO is discussed.

A Metal-Free Carbon-Based Catalyst: An Overview and Directions for Future Research

Metal-free carbon porous materials (CPMs) have gained the intensive attention of scientists and technologists because of their potential applications, ranging from catalysis to energy storage. Various simple and facile strategies are proposed for the preparation of CPMs with well-controlled sizes, shapes, and modifications on the surface. The extraordinary tenability of the pore structure, the environmental acceptability, the unique surface and the corrosion resistance properties allow them to be suitable materials for a large panel of catalysis applications. This review briefly outlines the different signs of progresses made towards synthesizing CPMs, and their properties, including catalytic efficiency, stability, and recyclability. Finally, we make a comparison of their catalytic performances with other nanocomposites, and we provide an outlook on the expected developments in the relevant research works.