The important role of N2H formation energy for low-temperature ammonia synthesis in an electric field

Development and Recent Progress on Ammonia Synthesis Catalysts for Haber–Bosch Process

“…Recently the use of an Fe catalyst supported on CeO 2 was shown to exhibit excellent activity at the extremely low temperature of 100 °C when the catalyst bed was exposed to an electric field. [ 83 ] At atmospheric pressure and 100 °C, the low‐Fe‐content 7% Fe–CeO 2 catalyst exhibited an activity of 155 μmol g −1 h −1 . Other catalysts with the same weight percentage on CeO 2 were also tested, including Ru, Ni, Co, Pd, and Pt, all of which showed activity at this low temperature; however, the Fe catalyst displayed the highest activity.…”

Recent progress in use and observation of surface hydrogen migration over metal oxides

“…Hydrogen migration plays an important role in various catalyses such as hydrogenation-dehydrogenation of hydrocarbon, 1-5 CO 2 reduction [6][7][8][9] and NH 3 synthesis. [10][11][12][13][14][15][16][17] However, the utilisation of hydrogen migration is not limited to catalysis. It is also fundamentally important for catalyst preparation, 18,19 hydrogen storage, 20,21 fuel cells and sensors.…”

“…[39][40][41] This active migration is called surface protonics. It has been revealed that surface protonics plays a key role in activating the cleavage of strong bonds, as in the NRN bond in N 2 , [13][14][15][16][17]42,43 and the C-H bond in hydrocarbons, as in CH 4 [42][43][44][45][46] and methylcyclohexane (MCH). 4,5 Those activations make it possible to catalyze hydrogen production and formation of the hydrogen carrier, even at low temperatures (o500 K).…”

“…To date, this method has been applied to various catalytic reactions, revealing that surface ion conduction participates in low-temperature catalysis. 39,40,84 Herein, we have described reaction mechanisms that are relevant to surface protonics under a H 2 atmosphere: NH 3 synthesis proceeds via N 2 H [11][12][13][14][15][16][17] and dehydrogenation of methylcyclohexane (MCH) facilitated by H + collision. Both compounds are promising hydrogen carrier candidates.…”

First observation of surface protonics on SrZrO3 perovskite under a H2 atmosphere

“…[4][5][6] Recently, an important role of surface protonics during heterogeneous catalytic reactions was found in an electric field under both H 2 O and H 2 atmospheres. [7][8][9][10][11][12][13][14][15][16][17][18][19] It promotes low-temperature catalysis for hydrogen production, ammonia synthesis, and other processes. Electrochemical impedance spectroscopy (EIS) of oxide surfaces under a H 2 O atmosphere has been investigated to elucidate the correlation between catalysis in an electric field and surface protonics (Scheme 1).…”