Regulating active hydrogen adsorbed on grain boundary defects of nano-nickel for boosting ammonia electrosynthesis from nitrate

Abstract

Electrochemical nitrate reduction reaction (NitRR) into ammonia is a promising route for sustainable ammonia synthesis under ambient conditions. Since hydrogen evolution reaction (HER) is its main competing reaction, many researchers...

Balanced NOx– and Proton Adsorption for Efficient Electrocatalytic NOx– to NH3 Conversion

“…The current density decreased with the addition of TBA, indicating that H* radicals did play a role in eNO 3 − RR. 44 The proton transfer rate during the eNO 3 − RR process was evaluated through the kinetic isotope effect (KIE) of H/D, which can be estimated using the ratio of current density in a purely protic medium and a purely deuterium medium (Figure S14a). 33,44 As shown in Figure S14b, the KIEs of Cu−Fe/Fe 2 O 3 and Fe/Fe 2 O 3 are 2.30/2.72, 1.76/1.96, and 1.53/1.63 at −0.25, −0.3, and −0.35 V, respectively.…”

Recent developments and prospects for engineering first-row transition metal-based catalysts for electrocatalytic NOx− reduction to ammonia

“…The construction of grain boundary defect engineering on nickel nanoparticles (GB Ni-NPs) is also well-suited to simultaneously achieving the availability of sufficient H* and suppressing competition from the HER. 93 As illustrated in Fig. 10c and d, the increased H* retention potential results from the GB region having a higher energy barrier for H 2 formation from H*.…”

“…Copyright 2021, American Chemical Society. (c) The simulated structure, (d) Gibbs free energy diagrams of the HER and (e) adsorption energies of important N-containing species on GB Ni and pristine Ni copied with permission 93. Copyright 2023, Royal Society of Chemistry.…”

Electrochemical Nitrate Reduction to Ammonia – Recent Progress

“…[56] Recently, a strategy has been developed for grain boundary defect engineering of nickel nanoparticles, which suppressed the electrocatalytic hydrogen evolution reaction (HER) by regulating the H* and enhanced the key ratedetermining step of NO 3 * to NO 2 * (Figure 8g-i). [57] Additional electron/chemical transfer through the interface could modulate thermodynamic reaction barrier of intermediates and inhibited the competitive hydrogen evolution reaction. [58] The Cu-Mn 3 O 4 heterostructure ultra-thin nano chip array with rich active sites, regulated electronic structure and interface synergy, promoted the adsorption and activation of nitrate, realized 95.8 % nitrate conversion (Figure 9a).…”