A rational design of electrocatalyst for oxygen reduction reaction (ORR) with activity 2–3 times higher than platinum has been of great demand for low temperature fuel cell applications. Particularly, metal-free ORR electrocatalysis has recently been explored rigorously because of limitations such as high price and scarcity of the state-of-the-art platinum catalyst. Here, we present a simple one-step method for the synthesis of carbon-doped hexagonal boron nitride (BNC) by a chemical vapor deposition method. An inert and insulating h-BN has been made active by carbon doping. From the structural analysis using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), we confirmed the formation of novel BNC nanostructures. BNC nanostructures exhibit rice grain-like shape having length ∼ 50 nm with interlayer distance of 0.34 nm, indicating hexagonal stacking of BN layers. As-synthesized BNC nanostructures obtained after annealing at 850 °C (BNC2-850) show interesting catalytic activity toward ORR with onset potential of 0.83 V versus RHE and a current density of 4.6 mA/cm2 in alkaline condition. More interestingly, the BNC2-850 nanostructures also reveal better stability even up to 10,000 potential cycles with concomitant negligible poisoning effect during methanol crossover process. Such a systematic and controlled study of carbon doping in h-BN nanostructures could certainly support the promising candidature of BNC as a metal-free electrocatalyst toward ORR.

Transition metals and metal oxides are carrying out vibrant role in electrooxidation of methanol. Unfortunately, the unclear cognition of methanol oxidation reaction (MOR) mechanism hampers the development of high performance electrocatalysts. Thus, in this report, a fascinating MOR mechanism has been studied using CoCuBi oxide foam structure, where the (220) plane of CoCuBi oxides are playing an exciting role in an unprecedented mechanism. Interestingly, the (220) plane belongs to the families of plane, where transition metal oxides prefer Eley‐Rideal (ER) mechanism with concomitant reduction in the poisoning effect due to CO. The synergetic effect of these planes triggers the excellent current density of 118 mA/cm2 with 50% retention of activity even after 10 h stability test. X‐ray photoelectron spectroscopy (XPS) and X‐ray diffraction (XRD) studies revealed different oxidation states of metal ions indicating formation of mixed oxides along with different phase formation in CoCuBi foam structure. More excitingly, CoCuBi nanocomposites show remarkable electrochemical methanol oxidation to form specific product such as formate, which is strongly confirmed by proton NMR spectroscopy.

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Transition metals have emerged as highly active catalysts for methanol oxidation reaction. The development of low-density metallic foams is exceedingly intriguing for various applications. Here, we report a systematic design of three-dimensional (3D) porous nanocomposites (foam) of transition metals like Cu and Ni with reduced graphite oxide (Cu–Ni@rGO) using simple self-propagation combustion method, where Cu–Ni foam structures are wrapped around reduced graphite oxide. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) show nanoporous structural morphology. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) show presence of different oxidation states of metal ions and phase formation, respectively. The electrochemical studies of Cu–Ni@rGO nanocomposites exhibit interesting methanol electrooxidation properties with exciting current density of 280 mA/cm2, which further retain 95% of their activity even after 600 s. In addition, these, Cu–Ni@rGO structures also reveal negligible poisoning effects during methanol electrooxidation. More interestingly, Cu–Ni@rGO nanocomposites show remarkable electrochemical CO oxidation to form CO2 and the evidence supports the Eley–Rideal mechanism of CO oxidation, where the presence of oxygen does not affect the oxidation process.

Summary Fabricating the significant electrocatalysts with enriched activity and stability is necessary due to the increasing demands of the fuel cell industries for its commercialization. This report provides a widespread impact on fabrication of a suitable and significant porous bimetallic nanocatalyst for methanol oxidation reaction (MOR). Here, we have developed nanofoams of Cu‐Co alloys/oxides with varied carbon supports using simple combustion method, where graphite oxide (GO) shows synergistic “catalyst‐support” effect than other substrates. The morphological studies reveal a honeycomb‐like structure with dense porous nature of Cu‐Co nanofoam (CuCo@rGO). X‐ray diffraction and spectroscopic studies reveal the formation of spinel structure of CuCo2O4 with active {110} facets in case of CuCo@rGO, exhibiting higher methanol electrooxidation activity of 198 mA/cm2, which is found to be improved than that of the previous reports. The optimized composition, CuCo@rGO shows the slow decrease in the current in chronoamperometric studies with 40% retention of its activity even after 10 hours. The CoCu@rGO nanofoam shows improved Brunauer‐Emmett‐Teller surface area of ~50 m2/g due to the addition of GO. In addition, the composite shows an excellent electrochemical surface area value of 7.75 m2/g over other compositions of different carbon supports. The intrinsic effect of better conductivity of Co75Cu25@rGO has also been confirmed using impedance spectroscopy. The porous honeycomb structure of Co75Cu25@rGO composite synergistically impacts methanol oxidation and also forbids the formation of CO intermediate, maintaining the activity.