The Kinetics of Ammonia Synthesis over Ru-Based Catalysts

Ammonia synthesis on graphitic-nanofilament supported Ru catalysts

“…However, the results from different H 2 /N 2 molar ratios show that a higher H 2 /N 2 molar ratio in the feed gas is not favorable to a higher activity at lower temperatures. This result is in agreement with previous reports [12,27,31], indicating that H 2 is an inhibitor, i.e. the active sites of Ru were covered by adsorbed hydrogen atoms which inhibit N 2 dissociation.…”

“…Therefore, a more stable support is required, and this has led to a search for an alternative to active carbon. Recently, a number of studies have shown that graphitzed activated carbon, MgO and BN supported Ru have high catalytic activities and long-term stability for ammonia synthesis [4][5][6][7][8][9][10][11][12][13].…”

Role of Steps inN2Activation on Ru(0001)

“…Measurements of the N 2 dissociation rate over Ru catalysts show a process with an activation barrier between 0.3 and 0.6 eV [6,7]. This is in fair agreement with a dissociation probability for nitrogen of 10 212 at 300 K measured over three different Ru surfaces [8].…”

The catalytic reduction of NO by H2 on Ru(0001): Observation of NHads species

“…[33] and references therein). Moreover, it has been proven that the first hydrogenation step of N ads to NH ads is the rate-determining step of ammonisation in co-adsorbed N ads /H ads layers [34]. Is the formation of the NH ads species observed in the present in contradiction with the already mentioned high selectivity to N 2 in the selective catalytic reduction of NO?…”