Atomic Structure Modification for Electrochemical Nitrogen Reduction to Ammonia

Abstract

The electrochemical nitrogen reduction reaction (NRR), as an environmentally friendly method to convert nitrogen to ammonia at ambient temperature and pressure, has attracted the attention of numerous researchers. However, when compared with industrial production, electrochemical NRR often suffers from unsatisfactory yields and poor Faraday efficiency (FE). Recently, various structure engineering strategies have aimed to introduce extra active sites or enhance intrinsic activity to optimize the activation and hydrogenation of N2. In this review, recent progress in atomic structure modification is summarized and discussed to design high‐efficiency NRR catalysts, with a focus on defect engineering (heteroatom doping and atom vacancy), surface orientation and amorphization, as well as heterostructure engineering. In addition, existing challenges and future development directions are proposed to obtain more credible NRR catalysts with high catalytic performance and selectivity.

Biomass-Derived Nitrogen-Doped Porous Carbon for Highly Efficient Ambient Electro-Synthesis of NH3

“…The N content in the catalyst NC-800 was estimated to be 3.05 wt% by elemental analysis (Table S1). The large electronegativity of N (3.04) incorporated into the carbon lattices could induce the modification of charge density, electronic structure, and polarization charge, which lead to the strong adsorption of N2 for NC [7]. The ambient NRR performance of NC-800 was conducted in a typical H-cell, separated by a piece of Nafion membrane in an N2-saturated HCl (0.1 M) electrolyte ( Figure S8).…”

“…Over the past few decades, great efforts have been devoted to the sustainable synthesis of NH 3 from nitrogen, including biomimetic catalysis, photo catalysis, and photo(electro)catalysis [5][6][7]. Apart from the development of synthetic strategies, the detection methods for quantification of the produced ammonia were also developed accordingly [8,9].…”

Defective S/N co-doped carbon cloth via a one-step process for effective electroreduction of nitrogen to ammonia

“…The change of the NRR performance is consistent with that of S and N content in CC-APS X, conrming that the co-doping of S-N heteroatom pairs may enhance the NRR performance of the carbon through a synergistic effect. [60][61][62] The doping quantity of N in CC-APS 800 is higher than many other N-doped carbon materials prepared through conventional thermochemical methods, [63][64][65] suggesting that introducing S as a secondary dopant may benet the codoping of N in carbon materials. Fig.…”

“…25 Recent literatures have reported the theoretical calculation results of the S/N-codoped graphene as the catalyst for NRR. 26,27 Due to the higher electronegativity of N (3.04) and S (2.58) relative to C (2.55), the N/S dopants can induce the positive charge densities on the adjacent carbon atoms, which favor the adsorption of N 2 . Thus, the N/S-adjacent carbon atoms act as the active sites for N 2 adsorption and subsequent activation.…”

Across the Board: Federico Bella on Electrochemical Nitrogen Reduction

“…The scientific community has recently come back to an old “Holy Grail” concept: trying to perform ammonia synthesis under mild conditions and without the huge constrains of the Haber–Bosch large‐scale (geo‐localized) plants. This challenge is extremely difficult because the aim is to completely eliminate carbon emissions and deliver both hydrogen and required power from renewable sources . This hot topic in the scientific literature (2018–today) has been approached through different research strategies: biochemical, photocatalytic, chemical looping, plasma‐chemical, and electrochemical.…”