Interfacial Sites between Cobalt Nitride and Cobalt Act as Bifunctional Catalysts for Hydrogen Electrochemistry

Abstract

Hydrogen (H 2 ) electrochemistry primarily consists of two reactions: hydrogen evolution reaction in water for H 2 production (HER) and hydrogen oxidation reaction in hydrogen fuel cells for H 2 utilization (HOR). The realization of future hydrogen economy necessitates the development of low-cost and competent electrocatalysts for both HER and HOR. Herein, we report that partial nitridation of cobalt nanoparticles on current collectors results in rich Co 2 N/Co interfacial sites, which exhibit bifunctional activity for hydrogen electrochemistry, rivaling the state-of-the-art Pt counterparts tested under similar conditions. Our combined experimental and theoretical computation results demonstrate that Co 2 N/Co interfacial sites not only possess optimal hydrogen adsorption energy but also facilitate water adsorption and dissociation on the catalyst surface, all of which are beneficial to the electrocatalytic performance for both HER and HOR. In addition, our Co 2 N/Co electrocatalysts also demonstrate great tolerance against CO poisoning during long-term H 2 oxidation.

Unveiling the Activity Origin of a Copper‐based Electrocatalyst for Selective Nitrate Reduction to Ammonia

“…The model showed the electron density of Cu in Cu/Cu 2 O NWAs minus the electron density of Cu in pure Cu NWAs, and the extra electronic cloud was the yellow part. Thus, it can be deduced that high electronic density of Cu induced the decrease of reaction barrier and suppresses the competitive H 2 production, leading to high conversion rate, Faradaic efficiency, and selectivity of Cu/Cu 2 O for NRA.…”

Manipulating dehydrogenation kinetics through dual-doping Co3N electrode enables highly efficient hydrazine oxidation assisting self-powered H2 production

“…Importantly, these two peaks are positively shifted to higher binding energies in PW-Co 3 N NWA/ NF. Specifically, the deconvoluted peaks at 778.6 and 793.9 eV can be assigned to metallic Co states in Co 3 N 30,31 while the peaks at 786.9 and 803.7 eV can be attributed to satellite peaks 29,32 . Two more peaks located at 782.4 and 799.2 eV could be originated from the surface oxidation, which has also been broadly observed 33,34 .…”

Insight into the hydrogen oxidation electrocatalytic performance enhancement on Ni via oxophilic regulation of MoO2

“…Moreover, Markovic and co-workers [21] demonstrated that optimizing adsorption of hydroxyl species (OH ad ) can promote hydrogen oxidation rate in alkaline media. Inspired by this, a series of electrocatalysts with bi-active sites consisting of metals and metal oxides/hydroxide have been reported, in which the metal acts as the hydrogen adsorption site and the other component promotes OH ad adsorption [22][23][24][25]. Ni/NiO/C with enhanced HOR performance in alkaline medium was synthesized by Sun's group [26].…”