Formation of N2O and (NO)2 During NO Adsorption on Au 3D Crystals

Abstract

The adsorption of NO on Au 3D hemispherical crystals (''field emitter tips'') has been studied by means of pulsed field desorption mass spectrometry (PFDMS) under dynamic gas flow conditions and at 300 K. Local chemical probing of $200 Au sites in the stepped surface region between the central (111) pole and the peripheral (001) plane leads to the detection of NO þ , N 2 O þ and (NO) þ 2 species. Obviously, molecular NO adsorption on stepped Au surfaces can lead to dimerization. Nitrous oxide formation probably occurs via the dimer, (NO) 2 .

Formation of unique trimer of nitric oxide on Cu(111)

“…8,9 It has been proposed that the catalytic reduction of NO proceeds via the formation of a (NO) 2 intermediate on Ag(111), [10][11][12][13] represented by 2NO → (NO) 2 → N 2 O + O. A similar catalytic reduction mechanism via dimer formation has been proposed on Cu, [14][15][16] Au, [17][18][19] and transition metal [20][21][22] surfaces. Moreover, NO dimers on coinage-metal surfaces have attracted attention because of their photochemical reactions such as NO desorption 23,24 and reductive N 2 O and N 2 formation.…”

CO Adsorption-Induced Surface Segregation and Formation of Pd Chains on AuPd(100) Alloy: Density Functional Theory Based Ising Model and Monte Carlo Simulations

“…Among bimetallic systems, gold alloyed with palladium has received particular attention because of its use in many catalytic reactions. For instance, in the selective reduction reaction of NO x species, the addition of Pd to Au may provide N–O bond-breaking capability, which is not the case over monometallic gold catalyst . Similarly, for the case of low-temperature CO oxidation reaction, because Pd is known to dissociate O 2 at temperature as low as 150 K, the idea of adding Pd to Au to favor the dissociation of O 2 is prone to improve the catalytic properties of gold.…”

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

“…First, the adsorption of NO on Au nanoparticles at 300 K was studied [221] and induced, in addition to the expected NO + , the presence of dimer (NO) 2 + , and of nitrous oxide N 2 O + species in the mass spectra. Previous works by kinetic analysis [222,223] suggested the formation of nitrous oxide via the combination of two NO(ads) molecules rather than decomposition of NO(ads) and recombination.…”

“…To prove the dissociation of NO, PFDMS measurements were performed and the mass spectra indicates the presence of N + , O + , NO + and NO 2 + species, proof of the NO dissociation and recombination on this alloy. This is in contrast to NO adsorption on pure Au where the formation of N 2 O was due to the dimerisation of NO rather than its dissociation [221]. Finally, FIM was used to image a catalytic reaction during the ongoing process [138]: a NO-precovered Au-62 at% Pd sample (NO exposure: t = 30 s, P NO = 3 × 10 −3 Pa, T = 450 K) was imaged in the presence of hydrogen.…”