The synergy between electrochemical substrate oxidation and the oxygen reduction reaction to enable aerobic oxidation.

Aerobic substrate oxidation reactions catalyzed by a heterogeneous catalyst can be looked upon as two independent half-cell reactions, viz. anodic substrate oxidation and the cathodic oxygen reduction reaction (ORR). In this context, Fe PANI/C, a well-known catalyst for the ORR, is chosen to validate this hypothesis, wherein the anodic reaction is hydrazine oxidation. Fe PANI/C shows excellent activity in terms of the electrochemical ORR and hydrazine oxidation in both alkaline aqueous and non-aqueous media and taken together the aerobic oxidation efficacy of hydrazine-like small organic molecules is correlated with the electrochemical outcomes.

In-Situ Growth of Urchin Manganese Sulfide Anchored Three-Dimensional Graphene (γ-MnS@3DG) on Carbon Cloth as a Flexible Asymmetric Supercapacitor.

In energy storage-device it is highly crucial to develop durable electrode materials having high specific capacitance and superior energy density without disturbing its inherent flexibility. Herein, we demonstrate three-dimensional graphene oxide decorated monodispersed hollow urchin γ-MnS (γ-MnS@3DG) via proficient one-step solvothermal method. The designed material delivers a remarkable capacitance of 858 F g-1 at 1 A g-1. A flexible solid state asymmetric supercapacitor (ASCs) device assembled using surface activated carbon cloth (CC) decorated with γ-MnS@3DG as positive and three-dimension graphene on carbon cloth (3DG@CC) as negative electrode, (γ-MnS@3DG//3DG). The device delivers 26 Wh kg-1 energy density at power density 500 W kg-1 @ 1A g-1 and retains favorable energy density 17.8 Wh kg-1 at an ultrahigh power density of 1500 W kg-1@3 A g-1. This carbon embedded transition-metal sulfide (TMS) based ASC demonstrates eminent mechanical flexibility under rigorous bending states maintaining invariant performance.

Bimetallic Phosphides for Hybrid Supercapacitors.

Supercapacitors (SCs) are considered promising energy storage systems because of their high power output and long-term cycling stability; however, they usually exhibit poor energy density. The hybrid supercapacitor (HSC) is an emerging concept in which two dissimilar electrodes with different charge storage mechanisms are paired to deliver high energy without sacrificing power output. This Perspective highlights the features of transition-metal phosphides (TMPs) as the positive electrode in HSCs. In particular, bimetallic nickel cobalt phosphide (NiCoP) with multiple redox sites, excellent electrochemical reversibility, and stability is discussed. We outline how the rational heterostructures, elemental variations, and nanocomposite morphologies tune the electrochemical properties of NiCoP as the positive electrode in HSCs. The Perspective further sheds light on NiCoP-based composites that help in improving the overall performance of HSCs in terms of energy density and cycling stability. The key scientific challenges and perspectives on building efficient and stable HSCs for future applications are discussed.