Nitrogen-doped graphene as a metal-free catalyst for oxygen reduction was synthesized by heat-treatment of graphene using ammonia. It was found that the optimum temperature was 900 °C. The resulting catalyst had a very high oxygen reduction reaction (ORR) activity through a four-electron transfer process in oxygen-saturated 0.1 M KOH. Most importantly, the electrocatalytic activity and durability of this material are comparable or better than the commercial Pt/C (loading: 4.85 µg_Pt cm⁻²). XPS characterization of these catalysts was tested to identify the active N species for ORR.

Cobalt phosphide is an effective electrocatalyst for NO ₃ ⁻ electroreduction into NH ₃ . Phosphorus is crucial for stabilizing the active phase and optimizing energy barriers, and Co 4p orbitals directly participate in the nitrate reduction.

Graphene nanosheets (GNSs) were synthesized and used as cathode active materials in a nonaqueous lithium-oxygen battery. The GNSs electrode delivered an extremely high discharge capacity in comparison to carbon powders, which is attributed to its unique morphology and structure.