Integrating Hydrogen Production and Transfer Hydrogenation with Selenite Promoted Electrooxidation of α-Nitrotoluenes to E-Nitroethenes

Developing an electrochemical carbon-added reaction with accelerated kinetics to replace the low-value and sluggish oxygen evolution reaction (OER) is markedly significant to pure hydrogen production. Regulating the critical steps to precisely design electrode materials to selectively synthesize targeted compounds is highly desirable. Here, inspired by the surfaced adsorbed SeOx2- promoting OER, NiSe is demonstrated to be an efficient anode enabling alpha-nitrotoluene electrooxidation to E-nitroethene with up to 99 % E selectivity, 89 % Faradaic efficiency, and the reaction rate of 0.25 mmol cm(-2) h(-1) via inhibiting side reactions for energy-saving hydrogen generation. The high performance can be associated with its in situ formed NiOOH surface layer and absorbed SeOx2- via Se leaching-oxidation during electrooxidation, and the preferential adsorption of two -NO2 groups of intermediate on NiOOH. A self-coupling of alpha-carbon radicals and subsequent elimination of a nitrite molecule pathway is proposed. Wide substrate scope, scale-up synthesis of E-nitroethene, and paired productions of E-nitroethene and hydrogen or N-protected aminoarenes over a bifunctional NiSe electrode highlight the promising potential. Gold also displays a similar promoting effect for alpha-nitrotoluene transformation like SeOx2-, rationalizing the strategy of designing materials to suppress side reactions.

Automated summary

A novel electrochemical carbon-added reaction using NiSe as an efficient anode has been developed to selectively synthesize E-nitroethene with high selectivity and efficiency. The high performance is attributed to the surface layer formed during electrooxidation and the preferential adsorption of intermediate on NiOOH. This study highlights the promising potential for energy-saving hydrogen generation and scaled-up synthesis of targeted compounds.