Carbon Nanocage Confining CuCo Bimetallic Interface with Low Nitrate Adsorption Energy for Highly Efficient Electrochemical Ammonia Synthesis

Abstract

This work aimed to improve the Faraday efficiency and formation rate of ammonia with a low reaction potential in the electroreduction of nitrate. For this purpose, CuCo bimetallic interface-rich catalysts confined in porous nitrogen-doped carbon nanocages (CuCo/NC) were designed. Results of in situ Fourier transform infrared spectroscopy suggested that the reaction path followed the sequence NO 3Density functional theory calculations revealed that the adsorption of nitrate over the CuCo bimetallic interface was thermodynamically favorable. CuCo bimetallic interface changed the rate-determining step of nitrate reduction at Cu sites from nitrate adsorption to *NO hydrogenation and promoted the continuous hydrogenation of nitrogenrelated intermediates. Over the CuCo/NC catalyst, Faraday efficiency and formation rate of ammonia were 95.1% (at −0.59 V vs reversible hydrogen electrode (RHE)) and 9110.8 μg h −1 mg cat.−1 (at −0.79 V vs RHE), which were higher than those over Cu/NC and Co/NC catalysts.

Recent Progress and Perspectives on Transition Metal-Based Electrocatalysts for Efficient Nitrate Reduction

“…In addition, the Co/NC-800 continued to have stable FE and NH 3 yields after 10 cycles of operation. Cheng et al immobilized CoCu bimetals in nitrogen-doped carbon nanocages. In situ Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) showed that the introduction of Co metal promoted electron transfer and enhanced the tendency of hydrogenation of adsorbed intermediates at the Cu active site.…”

“…Recently, besides the studies on the above-mentioned noble metal alloy catalysts, additional studies have been conducted on double transition metal alloys as well as Cu-based alloy catalysts, such as Cu-Ni, Cu-Co, ,− Cu-Pd, ,− Co-Ni, ,− and Co-Fe. , Results on electrochemical nitrate reduction using other metal alloy catalysts have also been obtained. Zhang et al synthesized a CuNi nanoalloy catalyst (CFP-Cu 1 Ni 1 ) on carbon-fiber paper, which allowed the metal nanoparticles to be well dispersed and the elements to be uniformly mixed.…”