Grain Boundaries Engineering of Hollow Copper Nanoparticles Enables Highly Efficient Ammonia Electrosynthesis from Nitrate

Abstract

Electrochemical nitrate (NO 3 -) reduction reaction (NO 3 -RR) represents as an ideal route for the production of ammonia (NH 3 ) under ambient conditions. Although a markedly improved NH 3 production rate has achieved on the NO -RR than the nitrogen reduction reaction (NRR), the NH 3 production rate of NO 3 -RR is still well below the industrial Haber−Bosch route due to the lack of robust electrocatalysts for yielding high current densities with concurrently good suppression of hydrogen evolution reaction (HER). Herein, we develop an in-situ electrochemical strategy for the synthesis of hollow carbon-coated Cu nanoparticles (NPs) with abundant grain boundaries (HSCu-AGB@C) for highly efficient NO 3 -RR in both alkaline and neutral media. Impressively, in alkaline media, the HSCu-AGB@C can achieve a maximum NH 3 Faradic efficiency of 94.2% with an ultrahigh NH 3 rate of 487.8 mmol g -1 cat h -1 at -0.2 V versus a reversible hydrogen electrode, more than 2.4-fold of the rate obtained on the Haber-Bosch. Both theoretic computations and experimental results uncover that the grain boundaries play the key to improve the NO 3 -RR performance. Provided here the industrial-scale NH 3 production rate may open exciting opportunities for the practical electrosynthesis NH 3 under ambient conditions.

Galvanic‐Cell Deposition Enables the Exposure of Bismuth Grain Boundary for Efficient Electroreduction of Carbon Dioxide

“…These results can be explained by the unsaturated coordination environment due to the presence of grain boundaries, which can alter the electronic structure of central Bi atoms and promote the electron transfer from Bi atoms to oxygen atoms of *OCHO. [ 25,42 ] Taken together, it can be reasonably concluded that the introduction of grain boundaries can enhance the CO 2 adsorption capacity and promote/stabilize the subsequent *OCHO intermediate formation, synergistically contributing to significantly enhanced CO 2 RR performance.…”

Mesoporous FeMoV Oxide Nanosheets Supported on Nickel Foam as Highly Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…40 According to previous reports, the C s value used for this calculation is 0.04 mF cm −2 . 40,50 As displayed in Figure S9, the Fe 0.5 Mo 0.1 V 0.4 /NF electrode still possesses the highest specific activity among all as-prepared catalysts, further suggesting that ECSA is not the key factor for enhanced OER activity.…”

“…The ECSA was calculated based on the C dl according to the equation: ECSA = C dl / C s , where C s is the capacitance of an atomically smooth planar surface of the material per unit area . According to previous reports, the C s value used for this calculation is 0.04 mF cm –2 . , As displayed in Figure S9, the Fe 0.5 Mo 0.1 V 0.4 /NF electrode still possesses the highest specific activity among all as-prepared catalysts, further suggesting that ECSA is not the key factor for enhanced OER activity.…”

Electronic Metal–Support Interaction Triggering Interfacial Charge Polarization over CuPd/N‐Doped‐C Nanohybrids Drives Selectively Electrocatalytic Conversion of Nitrate to Ammonia

“…Moreover, the competitive cathodic hydrogen evolution reaction (HER) also affects the faradaic efficiency (FE) of NH 3 production via eight-electron reduction of nitrate. [24,25] Therefore, to suppress N 2 formation and HER, the design and development of electrocatalysts with good activity, selectivity and stability is desirable yet challenging.…”