We describe the efficient purification of violet, blue, green and yellow emitting C-dots using a fast, low cost and scalable procedure based on solid phase extraction with alumina.

Graphene/metal nanocomposites have shown a strong potential for use in electronic applications. In particular, the combination of silver nanowires (AgNWs) with graphene derivatives leads to the formation of an efficient conductive network, thus improving the electrical properties of a composite. This work focused on developing highly conductive hydrophilic hybrids of simultaneously functionalized and reduced graphene oxide (f-rGO) and AgNWs in different weight ratios by following two different synthetic routes: (a) the physical mixture of f-rGO and AgNWs, and (b) the in situ reduction of GO in the presence of AgNWs. In addition, the role of AgNWs in improving the electrical properties of graphene derivatives was further examined by mixing AgNWs with a hybrid of few-layered graphene with functionalized multiwalled carbon nanotubes (FLG/MWNT-f-OH). The studied materials showed a remarkable improvement in the overall electrical conductivity due to the synergistic effect of their components, which was proportional to the percentage of Ag and dependent on the procedure of the hybrid formation. One of the f-rGO/AgNWs composites was also selected for the preparation of gravure printing inks that were tested to determine their rheological and printing properties. All of the f-rGO/AgNWs composites were shown to be very promising materials for use as conductive inks for flexible electronics.

This work provides a method for the development of conductive water-based printing inks for gravure, flexography and screen-printing incorporating commercial resins that are already used in the printing industry. The development of the respective conductive materials/pigments is based on the simultaneous (in one step) reduction of silver salts and graphene oxide in the presence of 2,5-diaminobenzenesulfonic acid that is used for the first time as the common in-situ reducing agent for these two reactions. The presence of aminophenylsulfonic derivatives is essential for the reduction procedure and in parallel leads to the enrichment of the graphene surface with aminophenylsulfonic groups that provide a high hydrophilicity to the final materials/pigments.

Platinum-based chalcogenides (PtX2) can be efficiently activated as electrocatalysts for water splitting through the hydrogen evolution reaction (HER). Edges in layered PtSe2 are effective in HER; however, the effect of edge interaction with conductive electrodes like graphene remains unclear. This study investigates the mechanism by which PtX2 (X = S, Se, Te) edges interact with graphene to uncover the origin of chalcogen-dependent differences in electrocatalysis through interfacial electronic coupling. Graphene flakes decorated with PtX2 nanosheets have reduced overpotential and enhanced kinetics in the HER. Interestingly, PtSe2/graphene exhibits the lowest overpotential among all samples, even though it also has the lowest electrochemically accessible surface area. First-principles calculations confirm the interfacial coupling between PtSe2 edges and graphene with pronounced charge accumulation in platinum-selenium edges. Gibbs free energy calculations show different activities for different chalcogens of PtX2/graphene, consistent with experimental results. Our findings indicate that graphene acts as an electronic regulator for PtSe2/graphene, which enhances the intrinsic catalytic activity of the platinum-selenium edge sites, making them more effective for the HER despite their lower density. This interfacial electronic coupling through conductive electrodes provides a powerful strategy for the rational design of next-generation electrocatalysts, enabling enhanced activity and selectivity in advanced electrochemical systems.