Selective electrocatalytic nitrobenzene-to-aniline reduction on nickel-cobalt layered double hydroxide via dual-site...

The selective reduction of nitrobenzene to aniline provides key intermediates for the industrial production of diverse chemical feedstocks and materials. Conventional synthesis routes typically operate under harsh conditions, such as elevated temperatures and pressures, posing significant challenges to sustainability and energy efficiency. The direct electrocatalytic reduction of nitrobenzene to aniline utilizing water as a green hydrogen source offers a promising solution. However, its industrial implementation is often hindered by low selectivity of catalytic electrodes. Herein, we report a highly efficient and selective electrocatalytic system for nitrobenzene-to-aniline reduction using nickel‑cobalt layered double hydroxide (NiCo-LDH) electrocatalyst. By precisely adjusting the ratio of nickel and cobalt metal cations and embedding acetate ions (Ac^-) into the LDH layers, a series of nickel foam-supported dual-site nickel‑cobalt layered double hydroxide electrodes (NiCo(x)-LDH-Y/NF) were prepared. The optimized NiCo(2)-LDH-20 electrode could achieve exceptional nitrobenzene conversion (>99 %) to aniline with 98.3 % selectivity and 87.3 % Faradaic efficiency under neutral conditions. Mechanistic investigations with electrochemical adsorption (ECA) studies and density functional theory (DFT) calculation revealed that the superior performance originates from a dual-site catalytic model of NiCo(x)-LDH-Y dominated by hydrogen atom transfer (HAT) process. The innovative integration of the basal plane sites in adsorbing substrate and edge sites in facilitating reactive hydrogen (H_ads) production remarkably improves the reaction pathway and overall performance of the catalyst.