Ammonia Decomposition in Electric Field over Ce‐based Materials

Abstract

Electric field‐induced decomposition of ammonia into hydrogen and nitrogen was investigated over CeO2, Fe‐, Ru‐ deposited CeO2, CePO4 and Sr‐doped CePO4, and CeZrO4 in a packed bed down‐flow reactor. The effect of applied current, concentration of ammonia in a feed, and residence time was examined using CeO2 alone. The conversion of ammonia was also studied with respect to a reduction temperature, loading and a type of the deposited metal. The activity results have been analyzed in terms of surface, morphological and electrical characterization of the catalysts. Among metal‐deposited catalysts, ammonia decomposition result at 4 mA was the best for 1 wt % Fe/CeO2 reduced at 550 °C, showing 22 % of conversion with 0.18 mmol of converted ammonia per kJ of energy consumed. The activity of studied Ce‐based catalysts normalized per mass of loaded catalyst showed an accordance in activity‐porosity relation.

Plasma Catalysis for Hydrogen Production: A Bright Future for Decarbonization

“…Additionally, reports have shown that adding an inert gas such as Ar increases the electron energy and enhances the electric field . This increases electron impact reaction with gas phase molecules and promotes plasma-phase chemistry. − There is also the potential to create metastable species, which undergo Penning ionization through impact collision and energy exchange with neutral species such as NH 3 . , …”

“…296−298 There is also the potential to create metastable species, which undergo Penning ionization through impact collision and energy exchange with neutral species such as NH 3 . 196,299 Fateev et al 299 demonstrated the influence of diluent when they investigated the plasma decomposition of an NH 3 /Ar stream. The authors studied different NH 3 composition ranges (0.1−10%) and observed that in the lower concentration…”

“…Energy efficiency versus H 2 yield in plasma-assisted processes from refs , , , , , , , − , − , − , , , and − (details are provided in the Supporting Information). …”

“… 296 − 298 There is also the potential to create metastable species, which undergo Penning ionization through impact collision and energy exchange with neutral species such as NH 3 . 196 , 299 …”

Recent Progress on Hydrogen Production from Ammonia Decomposition: Technical Roadmap and Catalytic Mechanism

“…One approach to improving the activity of these catalyst systems is to use rare earth element-based heteroatoms, such as La and Ce, for doping. This results in improving the surface properties, increasing the number of active sites, and enhancing the catalytic activity of Fe and Ni-based catalysts [ 39 , 40 , 41 , 42 , 43 ]. Another approach is to create multi-metal alloy-based structures, which can further enhance the catalytic activity by providing better dispersion of the metal atoms, improving the stability of the catalyst, and increasing the resistance to poisoning [ 28 , 44 , 45 , 46 , 47 , 48 , 49 ].…”