Promoted Ru on high-surface area graphite for efficient miniaturized production of hydrogen from ammonia

Abstract

Promoted Ru/C catalysts for decomposition of ammonia are incorporated into micro-fabricated reactors for the first time. With the reported preparation technique, the performance is increased more than two orders of magnitude compared to previously known micro-fabricated reactors for ammonia decomposition. The catalytic activities for production of hydrogen from ammonia are determined for different promoters and promoter levels on graphite supported ruthenium catalysts. The reactivity trends of the Ru/C catalysts promoted with Cs and Ba are in excellent agreement with those known from earlier studies of both ammonia synthesis and decomposition, and it is shown how proper promotion can facilitate ammonia decomposition at temperatures below 500 K.

Catalytic Ammonia Decomposition Over Ruthenium Nanoparticles Supported on Nano-Titanates

“…This shows that incorporating alkali metal promoters into the crystal lattice of the nano-titanates, gives a stronger promoting effect than surface deposition of the promoter on top of the ruthenium. The lower activity after promotion has not been seen in other studies were high cesium loadings has been impregnated on a ruthenium catalyst [29,32,43].…”

“…Several studies have shown that ammonia can easily be decomposed to CO x -free hydrogen [26][27][28]. Furthermore, studies of the optimal catalyst for the ammonia decomposition reaction have shown that ruthenium nanoparticles promoted with cesium and supported on graphitized carbon is the currently best catalyst candidate [29][30][31]. The general trend for the effect of the alkali metal promoters on ruthenium catalysts for ammonia decomposition has also been studied and found to be [32].…”

Ammonia as a Hydrogen Source for Fuel Cells: A Review

“…The support should be stable under reaction conditions and have a high specific surface area. For Ru catalyst, the various supports include silica, alumina, graphitized carbon, carbon nanotubes, and nitrogen doped carbon nanotubes [10,[19][20][21][22][23][24][25]. Yin et al [16] ranked the supports for Ru in order of decreasing activity measured by ammonia conversion rate: Carbon nanotube (CNT) > MgO > TiO2 > Al2O3 > ZrO2 > AC > ZrO2/BD.…”

Preparation of efficient ruthenium catalysts for ammonia synthesis via high surface area graphite dispersion

“…HSAGs are usually produced by mechanical treatment of natural or synthetic graphite. Because of its mesoporous structure, they have been investigated as the catalyst supports [14][15][16], adsorbents, fuel cell catalysts [17] and super capacitors [18]. The graphite degree and related electron conductivity of carbon play an important role in the catalytic activity both for ammonia synthesis and decomposition [19,20].…”