Electroreduction of Nitrite to Ammonia over a Cobalt Single-Atom Catalyst

Abstract

Electrochemical nitrite-to-ammonia reduction (NO 2 RR) holds great promise for converting harmful NO 2 − into valuable NH 3 . Herein, we develop Co single atoms dispersed on a C 3 N 4 substrate (Co 1 /C 3 N 4 ) as an efficient catalyst toward the NO 2 RR. Experimental and theoretical investigations reveal that single-atom Co sites can effectively active NO 2 − and optimize the formation energy of the key *NOH intermediate to promote the NO 2 − → NH 3 energetics. Remarkably, Co 1 /C 3 N 4 equipped in a flow cell delivers the exceptional NH 3 −Faradaic efficiency of 97.9% and NH 3 yield rate of 1080.3 μmol h −1 cm −2 at an industrial-level current density of 355 mA cm −2 , along with a long-term durability of 100 h of electrolysis, showing the considerable potential for practical NH 3 electrosynthesis.

P-Block Antimony–Copper Single-Atom Alloys for Selective Nitrite Electroreduction to Ammonia

“…In addition, compared to Cu, the Sb 1 site not only hampers H binding but also weakens the interaction between H and the Cu substrate (Figure S35), resulting in the overall HER suppression of Sb 1 Cu. These findings are further verified by molecular dynamics (MD) simulations, − revealing a stronger Sb 1 Cu/NO 2 – interaction than the Sb 1 Cu/H interaction (Figures S36–S39). Based on the radial distribution function results (RDF, Figure b,c), although Sb 1 Cu and Cu show a similar level of interaction with NO 2 – (Figure b), a much weakened interaction with H can be found for Sb 1 Cu compared to Cu (Figure c), thereby demonstrating that Sb 1 incorporation can effectively hinder the competitive HER toward the enhanced NO 2 RR selectivity of Sb 1 Cu.…”

NH3 Synthesis via Electrocatalytic N2 Reduction Reaction on the Defective Surfaces of Nb2Mo2C3Tx MXenes: Theoretical and Experimental Studies

“…On the other hand, transition-metal-based and nonmetal materials shared the advantages of low cost and abundance on earth, and they have shown potential use in NRR. − Previous studies illustrated that several transition-metal-based (Nb, Mo, Fe, and so on. ) − compounds showed high activity to NRR because of their great electronic conductivity and abundant bonding orbitals for N 2 fixation. − Specifically, the empty d orbitals of Nb 4+ in NbO 2 can strongly absorb N 2 molecules while a single d electron activated the NN bond. , Nb 2 O 5 nanofibers were also found to be able to catalyze NRR, but its selectivity of NH 3 production was poor. The active sites for N 2 adsorption and activation were supposed to be Nb atoms on the (181) crystal face.…”

Enhancing electrocatalytic N2 reduction to NH3 by introducing Ni heteroatoms into NiCuOx electrocatalyst

“…2,3 However, large-scale production of NH 3 heavily relies on the Haber–Bosch process, which requires harsh operation conditions (300–500 °C and 200–300 atm), substantial energy consumption (over 1% of the global energy supply), and considerable CO 2 emissions (1.5 tons CO 2 per ton NH 3 ). 4–8 Recently, the electrocatalytic N 2 reduction reaction (NRR), powered by renewable electricity under ambient conditions, has emerged as a promising green and efficient strategy. 9–12 Nevertheless, the significant overpotential required to drive the reductive adsorption of N 2 into N 2 H*, along with the competitive H 2 evolution reaction (HER) at similar potentials, leads to low productivity and selectivity in the NRR.…”