“Oxynitride trap” over N/S co-doped graphene-supported catalysts promoting low temperature NH3-SCR performance: Insight into the structure and mechanisms

Reduced graphene oxides (RG-Os) have attracted considerable interest, given their potential applications in electronic and optoelectronic devices and circuits. However, very little is known regarding the chemically induced reduction method of graphene oxide (G-O) in both solution and gas phases, with the exception of the hydrazine-reducing agent, even though it is essential to use the vapour phase for the patterning of hydrophilic G-Os on prepatterned substrates and in situ reduction to hydrophobic RG-Os. In this paper, we report a novel reducing agent system (hydriodic acid with acetic acid (HI-AcOH)) that allows for an efficient, one-pot reduction of a solution-phased RG-O powder and vapour-phased RG-O (VRG-O) paper and thin film. The reducing agent system provided highly qualified RG-Os by mass production, resulting in highly conducting RG-O(HI-AcOH). Moreover, VRG-O(HI-AcOH) paper and thin films were prepared at low temperatures (40 °C) and were found to be applicable to flexible devices. This one-pot method is expected to advance research on highly conducting graphene platelets.

Featured with unique mechanical, electronic and chemical properties, nitrogen‐doped carbon materials have become the research hotspot of energy storage. As electrode materials in supercapacitors (SCs), N‐doped carbons have demonstrated intriguing flexibility and superb performances in a wide electrochemical window, equipped with versatile properties as both cathodes and anodes for constructing high voltage devices. Compared with limited doping level, N‐rich and porous carbon materials (NPCs) are of great desire to release the restricted properties of N species and obtain high specific capacitances (>600 F g−1), pushing the energy density towards the battery level without scarifying the capacitor‐level power ability. In this Research News we firstly discuss the key factors influencing the performance of NPC electrodes to disclose related charge storage mechanisms. In addition, the trade‐off among N‐content, porous structure and electrical conductivity is involved as well as electrochemical behaviors in different electrolytes. Also, various progressive developments are highlighted systematically ranging from asymmetric to symmetric and hybrid configurations, covering both aqueous and non‐aqueous systems. Finally, some stubborn and unsolved problems are summarized, with prospective research guidelines on NPC‐based SCs.