Highly Selective Electrocatalytic Oxidation of Amines to Nitriles Assisted by Water Oxidation on Metal-Doped α-Ni(OH)₂

Abstract

Selective oxidation to synthesize nitriles is critical for feedstock manufacturing in the chemical industry. Current strategies typically involve substitutions of alkyl halides with toxic cyanides or the use of strong oxidation reagents (oxygen or peroxide) under ammoxidation/oxidation conditions, setting considerable challenges in energy efficiency, sustainability, and production safety. Herein, we demonstrate a facile, green, and safe electrocatalytic route for selective oxidation of amines to nitriles under ambient conditions, assisted by the anodic water oxidation on metal-doped α-Ni­(OH)2 (a typical oxygen evolution reaction catalyst). By controlling the balance between co-adsorption of the amine molecule and hydroxyls on the catalyst surface, we demonstrate that Mn doping significantly promotes the subsequent chemical oxidation of amines, resulting in Faradaic efficiencies of 96% for nitriles under ≥99% conversion. This anodic oxidation is further coupled with cathodic hydrogen evolution for overall atomic economy and additional green energy production.

Spinel-Derived Formation and Amorphization of Bimetallic Oxyhydroxides for Efficient Electrocatalytic Biomass Oxidation

“…Reaction orders can be obtained by plotting log­( j Fu/HMF ) versus log­( C Fu/HMF ) or log­( C OH – ). Importantly, a similar reaction order dependence was observed for Fu/HMF and OH – , which is consistent with a direct surface reaction mechanism between co-absorbed Fu/HMF substrate and active oxygenated species from partial OER …”

“…A key design principle in the electrocatalytic oxidation of biomass molecules is the participation of OER-initiated oxygen intermediate species. − , To this end, the intrinsic OER activity of a spinel catalyst presumably contributes equally to the final BEOR performance as the surface binding energy of the biomass molecules . To systematically probe the effects of these decisive factors, the correlation between OER and BEOR activities of a series of spinel catalysts was investigated, as shown in Figure c.…”

Origin of the Universal Potential-Dependent Organic Oxidation on Nickel Oxyhydroxide

“…The emerging hydrogen economy for sustainable energy systems has increased the demand for more efficient hydrogen production technologies. − One alternative to the prominent water splitting technologies is the paired electrolysis via cathodic hydrogen evolution and anodic organic oxidation, especially naturally available alcohols, aldehydes, and amines. − This route can not only replace the low-valued oxygen product with the value-added carboxylic acid or nitrile products but also require lower energy cost due to the higher reactivities of the organics, which together decrease the composite cost of hydrogen. ,, Nickel oxyhydroxide (NiO x (OH) 2– x , x = 1–2 depending on the oxidation state of Ni and phase structure of the pristine Ni­(OH) 2 ) is one of the most active catalysts toward the electrochemical selective oxidation of these organics. − ,,,− Its low cost, facile accessibility, scalable production, and widespread use in industrial alkaline electrolyzers have promoted the research focus as the potential electrocatalyst candidate. Thus, understanding the electrocatalytic mechanism on the nickel oxyhydroxide surfaces has become utterly important for the rational design of next-generation electrocatalysts with high efficiency and selectivity for organic oxidation …”

Electrocatalytic sulfion recycling assisted energy-saving hydrogen production using CuCo-based nanosheet arrays

“…[21][22][23] This hybrid water electrolysis system reduces the total energy consumption for efficient hydrogen production while gaining value-added products at the anode. 24,25 However, most of the above small molecule oxidation reactions involve multi-step oxidation processes, which are complex and have many kinds of products. Therefore, the implementation of hybrid water electrolysis systems for H 2 production remains a challenge.…”