Transition metal-nitrogen co-doped carbide-derived carbon catalysts for oxygen reduction reaction in alkaline direct methanol fuel cell

Nitrogen-Doped Hollow Carbon Spheres with Embedded Co Nanoparticles as Active Non-Noble-Metal Electrocatalysts for the Oxygen Reduction Reaction

“…For CoNHCS-900, the onset potential is close to that of CoNHCS-750 and better than CoNHCS-1050, so is half-wave potential. Moreover, CoNHCS-900 exhibits the highest limiting current density, which is comparable to the previously reported values of Co-doped carbon materials in the literature, for instance, Co-N-CDC [33], Co/carbon nanotubes [52], and Co-doped carbon microspheres [53]. A more positive onset potential and larger limiting current density are needed for ORR in catalysts.…”

“…During the heating process of CoCl 2 and NHCSs, the CoCl 2 loses lots of crystalliferous water at 110 • C and it reacts with carbon to form a Co substance when the temperature is above 400 • C. The catalysis of Co promotes the transformation of carbon spheres from amorphous to graphitic carbon. This phenomenon was explained by a dissolving-precipitating mechanism, which means that carbon can be solved with catalysts and part of the amorphous carbon changes to graphitic carbon [33]. The X-ray diffraction studies of the CoNHCSs, CoHCSs-900, and NHCSs samples were obtained for establishing the nature of the carbon and the Co active species.…”

“…The catalysis of Co promotes the transformation of carbon spheres from amorphous to graphitic carbon. This phenomenon was explained by a dissolving-precipitating mechanism, which means that carbon can be solved with catalysts and part of the amorphous carbon changes to graphitic carbon [33]. To understand the impacts of the embedded Co in the NHCS catalysts, an X-ray photoelectron spectroscopic (XPS) analysis was conducted.…”

Iron and Nitrogen Co‐doped Carbide‐Derived Carbon and Carbon Nanotube Composite Catalysts for Oxygen Reduction Reaction

“…This mixture is then pyrolyzed and the substrate along with inactive metal phases is removed by etching in acid mixtures, which allows for control over the porosity and structure by choosing the right substrate and reagents. [29][30][31][32][33] The main advantage of CDCs over other widely-used carbon supports is the amorphous nature and extremely high specific surface area that can be achieved (typically over 2000 m 2 g À1 ) [34] with highly reproducible largescale results already shown. [17] The resulting powder is then pyrolyzed to carbonize the MOF and dope it with transition metals and nitrogen, with the MOF playing a large role in directing the porosity and structure of the resulting catalyst.…”

“…[17] The resulting powder is then pyrolyzed to carbonize the MOF and dope it with transition metals and nitrogen, with the MOF playing a large role in directing the porosity and structure of the resulting catalyst. [36,37] As the pore size and specific surface area of the carbon support has been shown to influence the final porosity and thus activity of the doped catalyst, [31] CDCs open a pathway for rational design of catalysts not available by using typical carbon substrates. [26][27][28] Recently, carbide-derived carbons (CDC) have emerged as an effective carbon substrate for doping with iron and nitrogen for ORR electrocatalysis.…”