From an Fe2P3 complex to FeP nanoparticles as efficient electrocatalysts for water-splitting.

In large-scale, hydrogen production from water-splitting represents the most promising solution for a clean, recyclable, and low-cost energy source. The realization of viable technological solutions requires suitable efficient electrochemical catalysts with low overpotentials and long-term stability for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) based on cheap and nontoxic materials. Herein, we present a unique molecular approach to monodispersed, ultra-small, and superiorly active iron phosphide (FeP) electrocatalysts for bifunctional OER, HER, and overall water-splitting. They result from transformation of a molecular iron phosphide precursor, containing a [Fe2P3] core with mixed-valence FeIIFeIII sites bridged by an asymmetric cyclo-P(2+1) 3- ligand. The as-synthesized FeP nanoparticles act as long-lasting electrocatalysts for OER and HER with low overpotential and high current densities that render them one of the best-performing electrocatalysts hitherto known. The fabricated alkaline electrolyzer delivered low cell voltage with durability over weeks, representing an attractive catalyst for large-scale water-splitting technologies.

Electrochemical supercapacitors from conducting polyaniline-graphene platforms.

Energy storage devices such as electrochemical supercapacitors, with high power and energy densities are required to address the colossal energy requirements against the backdrop of global warming and the looming energy crisis. Nanocarbon, particularly two-dimensional graphene and graphene-based conducting polymer composites are promising electrode materials for such energy storage devices. Owing to their environmental stability, the low cost of polymers with high electroactivity and pseudocapacitance, such composite hybrids are expected to have wide implications in next generation clean and efficient energy systems. In this feature article, an overview of current research and important advances over the past four years on the development of conducting polyaniline (PANI)-graphene based composite electrodes for electrochemical supercapacitors are highlighted. Particular emphasis is made on the design, fabrication and assembly of nanostructured electrode architectures comprising PANI and graphene along with metal oxides/hydroxides and carbon nanotubes. Comments on the challenges and perspectives towards rational design and synthesis of graphene-based conducting polymer composites for energy storage are discussed.

Nitrogen-doped reduced graphene oxide electrodes for electrochemical supercapacitors.

Herein we use Nitrogen-doped reduced Graphene Oxide (N-rGO) as the active material in supercapacitor electrodes. Building on a previous work detailing the synthesis of this material, electrodes were fabricated via spray-deposition of aqueous dispersions and the electrochemical charge storage mechanism was investigated. Results indicate that the functionalised graphene displays improved performance compared to non-functionalised graphene. The simplicity of fabrication suggests ease of up-scaling of such electrodes for commercial applications.