Nonprecious transition metal nitrides as efficient oxygen reduction electrocatalysts for alkaline fuel cells

Abstract

Hydrogen fuel cells have attracted growing attention for high-performance automotive power but are hindered by the scarcity of platinum (and other precious metals) used to catalyze the sluggish oxygen reduction reaction (ORR). We report on a family of nonprecious transition metal nitrides (TMNs) as ORR electrocatalysts in alkaline medium. The air-exposed nitrides spontaneously form a several-nanometer-thick oxide shell on the conductive nitride core, serving as a highly active catalyst architecture. The most active catalyst, carbon-supported cobalt nitride (Co 3 N/C), exhibited a half-wave potential of 0.862 V and achieved a record-high peak power density among reported nitride cathode catalysts of 700 mW cm −2 in alkaline membrane electrode assemblies. Operando x-ray absorption spectroscopy studies revealed that Co 3 N/C remains stable below 1.0 V but experiences irreversible oxidation at higher potentials. This work provides a comprehensive analysis of nonprecious TMNs as ORR electrocatalysts and will help inform future design of TMNs for alkaline fuel cells and other energy applications.

Supercritical CO2-Built 2D FexN@FeOOH Heterostructures for Sustainable Sodium Ion Battery

“…The high-resolution Fe 2p XPS spectra of crystal Fe x N can be deconvoluted into Fe 2+ , Fe 3+ , Fe−N, and the related satellite peaks 25 (Figure 2b). In detail, the peaks located at 712.6 and 725.9 eV are related to Fe−N, 26 which are typical peaks of metal nitrides. The peaks at around 710.4 and 723.8 eV can be ascribed to Fe 2+ involved in Fe−N/ O.…”

“…The peaks at around 710.4 and 723.8 eV can be ascribed to Fe 2+ involved in Fe−N/ O. 26,27 The peaks centered at 712.9 and 727.0 eV are related to Fe 3+ . 28 Apparently, after SC CO 2 treatment, the Fe−N signals disappeared, and the other peaks shift to higher energy, indicating that the Fe−N bonds were broken and new bonds formed due to the effect of SC CO 2 .…”

A Critical Review on Artificial Intelligence for Fuel Cell Diagnosis

“…This sort of material may be created by packing nanostructured components into a catalytically active nanomaterial for electrocatalysis. Electrocatalysts ranging from Pt-group metals to C-based electrocatalysts have been created for both anodic and cathodic processes in various types of FCs [54][55][56][57]. For the evolution of sustainable energy technologies, the development of highly efficient and long-lasting electrocatalysts requires careful planning and synthesis.…”

Transition Metal Nitrides for Electrocatalytic Application: Progress and Rational Design

“…Transition metal nitrides (TMNs), formed by the insertion of electronegative nitrogen atoms into the interstitial sites of the parent species, are characterized by covalent compounds, ionic crystals, and transition metal features [ 19 , 20 ]. As a kind of non-noble metal material, TMNs exhibit similar surface and adsorption properties to the VIII group of precious metals (such as Pt and Pd) because the atomic distance between metal atoms increases and the d-band center downshifts after the incorporation of nitrogen atoms [ 21 , 22 ].…”