Electrocatalytic Synthesis of Essential Amino Acids from Nitric Oxide Using Atomically Dispersed Fe on N‐doped Carbon

Abstract

How to transfer industrial exhaust gases of nitrogen oxides into high‐values product is significantly important and challenging. Herein, we demonstrate an innovative method for artificial synthesis of essential α‐amino acids from nitric oxide (NO) by reacting with α‐keto acids through electrocatalytic process with atomically dispersed Fe supported on N‐doped carbon matrix (AD‐Fe/NC) as the catalyst. A yield of valine with 32.1 μmol mgcat−1 is delivered at −0.6 V vs. reversible hydrogen electrode, corresponding a selectivity of 11.3 %. In situ X‐ray absorption fine structure and synchrotron radiation infrared spectroscopy analyses show that NO as nitrogen source converted to hydroxylamine that promptly nucleophilic attacked on the electrophilic carbon center of α‐keto acid to form oxime and subsequent reductive hydrogenation occurred on the way to amino acid. Over 6 kinds of α‐amino acids have been successfully synthesized and gaseous nitrogen source can be also replaced by liquid nitrogen source (NO3−). Our findings not only provide a creative method for converting nitrogen oxides into high‐valued products, which is of epoch‐making significance towards artificial synthesis of amino acids, but also benefit in deploying near‐zero‐emission technologies for global environmental and economic development.

Tandem Dual-Site PbCu Electrocatalyst for High-Rate and Selective Glycine Synthesis at Industrial Current Densities

“…18,19 On the other hand, the key processes of glyoxylic acid formation and oxime hydrogenation suffer from poor selectivity and sluggish rate (Figure 1A). 20 Therefore, this puts high demands on the electrocatalyst design to have the capability to effectively convert the reactants and intermediates, 22 which might feed back to the high rate and selectivity for glycine formation (Figure 1B). In light of this, we consider designing stable dual-site metal catalysts to match the multistep reaction pathways in glycine formation.…”

“…These advances prompt us to consider whether electrocatalysis can be used to synthesize the value-added amino acid product. Fortunately, some studies have initially shown the possibility of synthesizing glycine from carbon and nitrogen monomers such as keto acids, oxalic acid, hydroxylamine, and nitrate. − However, it is urgent to simultaneously achieve the high selectivity (>60%) and high current density (>100 mA cm –2 ) for the industrially relevant requirements. In particular, using widely accessible chemicals as reaction monomers is expected to expand the scope of resource utilization.…”

“…Unfortunately, this expectation is far from being realized due to several key obstacles. On the one hand, the synthesis of glycine molecular involves long pathways and multiple reactions. , On the other hand, the key processes of glyoxylic acid formation and oxime hydrogenation suffer from poor selectivity and sluggish rate (Figure A) . Therefore, this puts high demands on the electrocatalyst design to have the capability to effectively convert the reactants and intermediates, which might feed back to the high rate and selectivity for glycine formation (Figure B).…”