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In this work, efficient methanol oxidation fuel cell catalysts with excellent stability in alkaline media have been synthesized by including transition metals to the layered double hydroxide (LDH) nanohybrids. The nanohybrids CoCr-LDH, NiCoCr-LDH and NiCr-LDH were prepared by co-precipitation and their physicochemical characteristics were investigated using TEM, XRD, IR and BET analyses. The nanohybrid CoCr-LDH is found to have the highest surface area of 179.87 m2 g−1. The electrocatalytic activity measurements showed that the current density was increased by increasing the methanol concentration (from 0.1 to 3 M) as a result of its increased oxidation at the surface. The nanohybrid NiCr-LDH, showing the highest pore size (55.5 A) showed the highest performance for methanol oxidation, with a current density of 7.02 mA cm−2 at 60 mV s−1 using 3 M methanol. In addition, the corresponding onset potential was 0.35 V (at 60 mV s−1 using 3 M methanol) which is the lowest value among all other used LDH nanohybrids. Overall, we observed the following reactivity order: NiCr-LDH > NiCoCr-LDH > CoCr-LDH, as derived from the impedance spectroscopy analysis.

A comprehensive overview and description of crumpled graphene explored in recent years for energy storage applications is presented. Although graphene is known as one of the best electronic materials, preparation of crumpled graphene has been less explored. This article selectively aims to present an overview of the advancement of research in crumpled graphene, in the areas of preparation and applications especially in energy storage, such as supercapacitors and lithium ion batteries. When graphene is transformed ino the crumpled form, the resulting material can give superior capacitance due to its unique properties like extremely high specific surface area, high conductivity and stability against graphitization (aggregation-resistant) compared to those of flat graphene sheets which tend to aggregate and thus lead to a dramatic decrease in the surface area, leading to poor capacitance.