Mechanocatalysis: Simple and Rapid Mechanochemical Synthesis of Ammonia in Hydrogen, Nitrogen, and Water System

Abstract

Mechanical force‐induced N2 fixation is an emerging strategy for single‐step ammonia synthesis under room temperature and atmospheric pressure. Here, we demonstrate a simple and rapid approach to synthesize NH3 in the N2+H2+H2O system and illustrate the reaction mechanism by theoretical calculations. The NH3 generation rate can reach 2.847 mg L−1 h−1 with an NH4+ selectivity of 99.45 wt.%. The presence of H2 can inhibit oxidation reactions to form NO3− by‐products and promote proton generation from H2O dissociation. The calculated formation energy of H‐adatom and OH‐adatom from H2O cleavage is −2.86 eV in N2+H2+H2O system, much lower than that in N2+H2O system, verifying much easier dissociation of H2O molecules and significantly facilitated proton generation to enlarge the NH4+ yield. This work provides a simple approach to improve mechanochemical N2 fixation performance and highlights a proton generation enhancement mechanism.

Ammonia Synthesis by Mechanochemistry

“…The incorporation of the bimetallic RuCo species on the support matrix of MgTiO 3 was achieved by mechanical activation, whilst the catalyst was then used in the ammonia synthesis process under nontermal plasma conditions, carrying it out inside a dielectric barrier discharge (DBD) plasma reactor. Lastly, in 2023, Cui and Chen furnished an alternative and miscellaneous procedure involving a mechanocatalytic N 2 /H 2 /H 2 O system promoted by 304 stainless steel balls and jar [44] . The presence of H 2 is beneficial for the inhibition of NO 3 − pathway shown in Figure 3, by likely consuming all the reactive oxygen species formed during the reaction mechanism.…”

“…Lastly, in 2023, Cui and Chen furnished an alternative and miscellaneous procedure involving a mechanocatalytic N 2 /H 2 /H 2 O system promoted by 304 stainless steel balls and jar. [44] The presence of H 2 is beneficial for the inhibition of NO 3 À pathway shown in Figure 3, by likely consuming all the reactive oxygen species formed during the reaction mechanism.…”