Nitrogen‐Doped Carbon Electrocatalysts Decorated with Transition Metals for the Oxygen Reduction Reaction

Abstract

The high cost of catalysts is the main disadvantage of aqueous fuel cells. In a conventional fuel cell, both the anode and cathode reactions need Pt‐based catalysts to catalyze the respective electrochemical reactions, for example, the oxygen reduction reaction (ORR) on the cathode. As the ORR is very sluggish, more Pt catalyst is needed to balance the anode and cathode currents. In recent years, many alternative catalysts have been explored for the ORR that are mostly based on carbon, which include nonmetal‐decorated carbons and metal‐decorated carbons. Carbons codoped with a transition metal and nitrogen have shown the best ORR performance among all nonprecious metal catalysts, which is comparable to Pt under analogous conditions. We review nitrogen‐doped carbon nanomaterials decorated with transition metals as ORR catalysts, their synthesis, characterization, and performance, with special emphasis on the mechanism and theoretical aspects of the ORR.

Co-based heterogeneous catalysts from well-defined α-diimine complexes: Discussing the role of nitrogen

“…Consequently, it is possible to modify the activity and adjust the selectivity of the final catalytic material towards the desired transformation. Among the various dopants, nitrogen attracted most interest [15,[20][21][22]. and applications of transition metal/N-doped graphene (NGr) based catalytic systems ranges from oxygen reduction reactions (ORR) [23][24][25][26], hydrogen evolving reactions (HER) [27,28], photocatalysis [29,30], oxidation [31][32][33][34][35][36][37][38], and reduction [39][40][41][42][43][44] reactions of organic…”

“…As a matter of fact, these elements are among the most abundant metals in the Earth's upper crust, thus being readily accessible [11]. Recently, heteroatom-doped carbon materials attracted major interest in the field of metal supported heterogeneous catalysts for both chemical synthesis [12][13][14] and/or energy-relevant transformations [15,16]. Indeed, doping graphene with heteroatoms such as N, B, P, or S leads to a radical modification of the electronic properties of both the support and the supported metal [17][18][19].…”

Transition Metal‐Nitrogen‐Carbon Active Site for Oxygen Reduction Electrocatalysis: Beyond the Fascinations of TM‐N4

“…For example, the Fe−N 2 and N−FeN 2+2 were demonstrated to be more effective than FeN 4 site. Some excellent works and reviews have miscellaneous information about the FeN x active sites ,,. ii) Various nitrogen types such as pyridinic N, pyrrolic N and graphite N were considered to be the active sites for heterogeneous nanocarbon materials .…”

Enhancement of the electrocatalytic oxygen reduction reaction on Pd3Pb ordered intermetallic catalyst in alkaline aqueous solutions

“…Platinum (Pt) is the most efficient catalyst for the ORR at PEMFCs, but the high cost and poor poison resistance of Pt-based PEMFC technology are major problems hindering its commercialization [5][6][7]. Therefore, it is urgent to develop a low-cost electrocatalyst with highly improved kinetics toward the ORR [8]. To achieve these requirements, several methods have been developed, such as using nanostructures to increase the surface-to-volume ratio [9], using an alloying technique to incorporate non-precious metals into the nanostructures, and replacing core atoms in Pt nanoparticles (NPs) with a non-precious metal [10].…”

“…Thus, researchers have focused on a wider selection of elements as electrocatalysts instead of Pt in an alkaline environment [11,12]. Palladium (Pd) is a promising substitute for Pt because the Pd catalyst possesses intrinsic electrocatalytic performance toward the ORR in alkaline media [8,13,14]. Other attractive aspects are that Pd is much more abundant and is less expensive than Pt [15].…”