Vacancy‐Rich Ni(OH)₂ Drives the Electrooxidation of Amino C−N Bonds to Nitrile C≡N Bonds

Abstract

Electrochemical synthesis based on electrons as reagents provides a broad prospect for commodity chemical manufacturing. A direct one‐step route for the electrooxidation of amino C−N bonds to nitrile C≡N bonds offers an alternative pathway for nitrile production. However, this route has not been fully explored with respect to either the chemical bond reforming process or the performance optimization. Proposed here is a model of vacancy‐rich Ni(OH)2 atomic layers for studying the performance relationship with respect to structure. Theoretical calculations show the vacancy‐induced local electropositive sites chemisorb the N atom with a lone pair of electrons and then attack the corresponding N(sp3)−H, thus accelerating amino C−N bond activation for dehydrogenation directly into the C≡N bond. Vacancy‐rich nanosheets exhibit up to 96.5 % propionitrile selectivity at a moderate potential of 1.38 V. These findings can lead to a new pathway for facilitating catalytic reactions in the chemicals industry.

Active/Conductive Layer Stacked Superlattices for Highly Selective CO2 Electroreduction

“…Along the way, substantial efforts have been devoted to exploring the e cient catalysts derived from these metal oxides 17,18,19,20,21,22 . However, with this selfreduction, the competitive hydrogen evolution reaction (HER) performance of the derived metal catalysts will gradually dominate 1,16,22,23,24,25,26 , resulting in their CO 2 RR activity are di cult to maintain in a wide potential window. Actually, this spontaneous self-reduction of metal oxides is contradictory to the high selective CO 2 RR performance.…”

High‐efficiency electrolysis of biomass and its derivatives: Advances in anodic oxidation reaction mechanism and transition metal‐based electrocatalysts

“…For instance, Wang et al obtained ultrathin Ni(OH) 2 nanosheet with abundant vacancies (VR-Ni(OH) 2 ) by in situ electrochemical conversion of Ni-MOFs nanosheets and used it in the propylamine electro-oxidation reaction (Figure 9A and B). [19] The oxidation reaction on the vacancy-rich nanosheet only required a small voltage of 1.36 V to output a current density of 10 mA cm -2 , which was lower than that (1.42 V) of vacancy-poor Ni(OH) 2 [VP-Ni(OH) 2 ] (Figure 9C). At the same time, the Faraday efficiency of propylamine conversion to propionitrile was very high, that is, 96.5% at a potential of 1.38 V. The distinction of the catalyst was further demonstrated by a small cell voltage in the assembled CoS 2 -MoS 2 ||VR-Ni(OH) 2 electrolyzer (1.46 V), which was also much lower than the conventional water splitting (1.74 V).…”

“…BEOR follows different reaction pathways depending on the used electrode type, the electrode potential, the electrolyte medium and other parameters, and consequently leads to formation of different products. Researchers usually propose the reaction pathways of a BEOR by combining theoretical calculations with the in-situ detection of oxidation reaction products and intermediates using various spectroscopy techniques such as Raman spectroscopy, [18] nuclear magnetic resonance (NMR) spectroscopy, [19,20] X-ray absorption near edge structure (XANES), [21] surfaceselective vibrational spectroscopy [22] and Fourier transform infrared (FTIR) spectroscopy etc. [23] In the following discussion we focus on the electrooxidation reaction pathways reported thus far for several representative biomass feedstocks and biomass derivatives, including alcohol, aldehyde, urea, amine, and lignin, as sketched in Scheme 2.…”

“…Transitional metal oxides of different compositions and morphologies are the second category of compound that is of great importance in the electrooxidation of biomass and biomass derivatives, especially urea. In a recent report by Wu et al, porous and hollow Ni 0.9 Fe 0.1 O x microspheres were used for bifunctional electrocatalytic urea splitting in a hybrid water electrolysis system, in which a low voltage of 1.455 V was required to reach a current density [19] Copyright 2020, Wiley-VCH of 10 mA cm -2 and no potential increase was observed after 25 hours operation. [72] Similarly, in another report NiFe 2 O 4 nanoparticles exhibited excellent urea electrooxidation activity and the authors attributed the excelling catalytic activity to the high conductivity of this material, large effective area, and rich defective sites obtained during synthesis.…”

“…CuCo 2 O 4 1 M KOH + 50 mM 5hydroxymethylfurfura 2,5-furandicarboxylic acid 1.40 V [74] 2020 Ni(OH) 2 nanosheet 1 M KOH+10 mmol propylamine propionitrile 1.36 V [19] 2020…”