Kinetics of nitric oxide decomposition on silica-supported rhodium

Catalysis for NOx abatement

“…NO uptake also diminished on reduced Pt/TiO 2 [27]. A similar observation has been made with Rh/TiO 2 [28,29]. The room-temperature chemisorption of NO was observed to decrease with increasing catalyst reduction temperature.…”

“…The Gothenburg protocol establishes reductions of four main pollutants to reduce acidification, eutrophication and the effect of ozone. Other than Canada and USA, 29 NO has an unpaired electron in its 2p * orbital and this has led to the notion that amphoteric bonding for NO on a surface is a useful consideration. NO can either donate its electron to the surface (like CO) or it can accept electron density from the surface into the half-filled 2p * orbital, and therefore show a very wide variety of chemistry on surface.…”

In situ infrared study of catalytic decomposition of NO. Semiannually technical progress report, August 1, 1995--February 1, 1996

“…The absence of an 0 2 profile in Figure 2 is consistent with the literature in that the oxygen produced from NO decomposition was not readily desorbed below 723 K [15,19,20]. During NO TPD, the 0 2 desorption peak occurred at 1,500 K on Rh(ll1) [15], 1060 K on 5% Rh/SiOz catalyst [19], and 1,100 K on Rh filament [20].…”

“…Dissociation of the high wavenumber Rh-N06-is not a common rate-determining step for the formation of N2 and N20. Simulation of TPD profiles for adsorbed NO have revealed that both steps (c) and (d) have the same activation energy on a 5 % Rh/SiO2 [19]. The factors that direct the reaction selectivity toward either (c) or (d) remajn to be investigated.…”

“…During NO TPD, the 0 2 desorption peak occurred at 1,500 K on Rh(ll1) [15], 1060 K on 5% Rh/SiOz catalyst [19], and 1,100 K on Rh filament [20].…”