Recently, heteroatom doped core–shell nanostructures (HCSNs) have been widely used as superior electrocatalysts for oxygen reduction reactions (ORRs) owing to their enhanced ORR performance and stability under harsh environmental conditions....

Metal-organic framework (MOF) are a kind of highly organized porous crystalline material that has attracted significant interest in several applications, including chemical sensors, organic-, photo-, and electrocatalysis, and energy and environmental applications. [1][2][3][4][5][6] Yaghi et al. are pioneers in the development of MOF-based porous materials using organic linkers and metal-oxide clusters as anchors to create open frameworks. [7] MOFs are readily manufactured by reacting metal ions or clusters with organic linkers in the presence of aqueous or organic solvents at certain temperatures, resulting in crystalline powders or granules. [8] The use of solvent is also playing an effective role in the synthesis of uniform MOFs in addition to other parameters. The solvent used in synthesis remains inside the pores of the collected crystalline framework. These holes may be cleaned out using a more volatile solvent and vacuum-aided desorption, leaving behind an enormous void pore volume. [8] These activated MOFs are calcined further to operate for target-specific analyte adsorption and applications. By varying the chemical compositions of metal and organic linkers, a highly adaptable and adjustable porous architecture may be readily created. [9] MOFs may also provide different internal surfaces with distinct accessible metal sites, various structural topologies, and chemical variety, such as the usage of

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The facile one-pot synthesis of sulfur-doped reduced graphene oxide results in a high powder density and easily reproducible electrode material.

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The research on cobalt‐based bimetallic hydroxides has led to their emergence as an effective electrocatalyst for oxygen (OER) and hydrogen evolution processes (HER) to split water and replace state‐of‐the‐art efficient noble metals. It is imperative to conduct both the OER and HER in the same electrolyte, hence it is necessary to adjust the material‘s characteristics to be compatible for this application. Due to the Co3+ active site, Co(OH)2 is electrochemically oxidized to CoOOH and exhibits outstanding OER kinetics. The incorporation of Mn into the cobalt hydroxide matrix increases the surface area while balancing the ratio of *OH to *O radicals to increase electrocatalytic activity. The complementary effects of the two metal hydroxides (Co and Mn) reveal a fresh perspective on the next‐generation electrocatalyst. The OER and HER reactions are both optimized using an easy electrodeposition method. The best HER and OER as two‐electrode electrolyzers displayed a cell voltage of 1.69 V at 10 mA/cm2 in alkaline electrolyte. Interestingly, when the state of art material Pt deposited on nickel foam substrate used for HER and the best CoMn hydroxide used for OER exhibits a cell voltage of only 1.55 V to drive the current density of 10 mA/cm2.

Graphene is a well-known two-dimensional material with a large surface area and is used for numerous applications in a variety of fields. Metal-free carbon materials such as graphene-based materials are widely used as an electrocatalyst for oxygen reduction reactions (ORRs). Recently, more attention has been paid to developing metal-free graphenes doped with heteroatoms such as N, S, and P as efficient electrocatalysts for ORR. In contrast, we found our prepared graphene from graphene oxide (GO) by the pyrolysis method under a nitrogen atmosphere at 900 °C has shown better ORR activity in aqueous 0.1 M potassium hydroxide solution electrolyte as compared with the electrocatalytic activity of pristine GO. At first, we prepared various graphene by pyrolysis of 50 mg and 100 mg of GO in one to three alumina boats and pyrolyzed the samples under a N2 atmosphere at 900 °C. The prepared samples are named G50-1B to 3B and G100-1B and G100-2B. The prepared GO and graphenes were also analyzed under various characterization techniques to confirm their morphology and structural integrity. The obtained results suggest that the ORR electrocatalytic activity of graphene may differ based on the pyrolysis conditions. We found that G100-1B (Eonset, E1/2, JL, and n values of 0.843, 0.774, 4.558, and 3.76) and G100-2B (Eonset, E1/2, and JL values of 0.837, 0.737, 4.544, and 3.41) displayed better electrocatalytic ORR activity, as did Pt/C electrode (Eonset, E1/2, and JL values of 0.965, 0.864, 5.222, and 3.71, respectively). These results display the wide use of the prepared graphene for ORR and also can be used for fuel cell and metal–air battery applications.