Remarkable CO_x tolerance of Ni³⁺ active species in a Ni₂O₃ catalyst for sustained electrochemical urea oxidation

Abstract

The electrochemical urea oxidation reaction (UOR) provides a cost-effective way of generating hydrogen owing to its low thermodynamic energy barrier. Although UOR is an effective way to generate hydrogen, sustained...

Ultrathin Atomic Layer Deposited Al2O3 Overcoat Stabilizes Al2O3-Pt/Ni-Foam Hydrogenation Catalysts

“…The O 1s spectrum was fitted to two peaks at the BE of 529.1 and 530.9 eV attributed to the lattice oxygen of Ni- and Al-oxides and adsorbed oxygen, respectively (Figure b). − The high-resolution Ni 2p spectrum can be deconvoluted into two doublet peaks (Figure c). The Ni 2p 3/2 peak at 853.6 eV is assigned to Ni(0), and the broad component at 855.3 eV is assigned to Ni-oxides, NiO and Ni 2 O 3 . − The BE appears to be red-shifted compared to that reported for Ni 2 O 3 and slightly blue-shifted from that of NiO, commensurate with an NiO- and Ni 2 O 3 -passivated surface, with some regions of subsurface metallic Ni. These observations are consistent with the TEM and EELS analysis that Ni 2 O 3 species are present but not uniformly distributed throughout the surface regions.…”

Self-assembled c-oriented Ni(OH)2 films for enhanced electrocatalytic activity towards the urea oxidation reaction

“…5b), typically due to the inception of strongly adsorbed intermediates. 44–47 This observation may explain the discernable passivation effect noticed in Ni(OH) 2 -gPF, 45 evidencing that self-assembled c -oriented Ni(OH) 2 films proficiently mitigate the genesis of such intermediates and the passivation trend.…”

Modulation Strategies for the Preparation of High‐Performance Catalysts for Urea Oxidation Reaction and Their Applications

“…In fact, Co(NH 2 ) 2 and H 2 O adsorption on the catalyst surface also compete with each other in the UOR process under alkaline conditions with high anode potential. [45,46] John et al explored the effect of KOH [47] Copyright 2022, Royal Society of Chemistry. e) LSV polarization curves of the LDH samples recorded for UOR in 1.0 m KOH + 0.33 m urea.…”

“…[ 45,46 ] John et al explored the effect of KOH concentration and urea concentration on the UOR activity of Ni 2 O 3 . [ 47 ] As shown in Figure a, with the increase of the amount of urea added, in 1 m KOH solution, UOR activity will gradually increase until saturation. This is because urea concentration is low, so the coverage of urea molecules on the catalyst surface is low.…”

“…c,d) magnified view CVs of c) NiO, d) Ni 2 O 3 , in 1-8 m KOH. a-d) Reproduced with permission [47]. Copyright 2022, Royal Society of Chemistry.…”