Realization of Platinum Nitride and Study of reaction with gas molecules

本研究的目的是实现不能用常规方法合成的氮化铂。当吸附在铂(111)上的一氧化氮(NO)被紫外光或电子照射时，建议将其解离。为此，我们研究了NO在铂(111)面上的吸附和解吸，以及在紫外光和电子辐照下的解吸/解离。尽管铂具有催化作用，但NO不能在铂(111)面上解离，它只能在低温下吸附，并通过加热解吸。随着NO覆盖率的增加，NO首先吸附在3重fcc中空位，然后是1重顶位，最后是3重hcp中空位。从热脱附谱(TDS)中的脱附峰得到了吸附能。用~(14)NO和~(15)NO研究了吸附在不同位置的NO物种之间的相互作用。用扫描隧道显微镜(STM)观察了吸附结构，并用扫描隧道显微镜(STM)尖端注入电子的方法研究了电子辐照对吸附结构的影响。STM尖端的电子辐照可使顶位的NO物种脱附，而15 eV以上的电子辐照可使面心立方中空位的NO物种解离。辐照后的扫描隧道显微镜观察发现有许多细小的波纹，这可能是NO的解离产物。NO物种占据hcp空位，虽然其吸附能很小，但影响了NO在fcc空位和顶位上的扩散。结果表明，在P1(111)晶面上，NO的活性可以通过占据HCP空位来控制。

The purpose of this study is to realize the platinum nitride which cannot be constructed by usual way. When nitric oxide (NO) adsorbed on Pt(111) is irradiated by ultra-violet (UV) light or electron, it is suggested to be dissociated. For this purpose the adsorption and desorption of NO on Pt(111), and the desorption/dissociation by UV or electron irradiation was studied.In spite of the catalytic ability of Pt, NO cannot be dissociated on Pt(111), it just adsorbs at low temperature and desorbs by heating. When the NO coverage is increased, NO first adsorbs on the 3-fold fcc hollow site, next on the 1-fold atop site and last on the 3-fold hcp hollow site. The adsorption energy was obtained from the desorption peak in the thermal desorption spectra (TDS). The interaction between the NO species adsorbed on the different sites was precisely studied by using the NO isotopes, 14NO and 15NO. The adsorption structure was observed by the scanning tunneling microscopy (STM) and the effect of electron irradiation was studied by electron injection from the STM tip.The NO species on the atop site can be desorbed by the electron irradiation from the STM tip, while the NO species on the fcc hollow site is suggested to be dissociated by the electron irradiation above 15 eV. The STM observation after irradiation revealed many small corrugation, which is suggested to be the dissociated products of NO. The occupation of the hcp hollow site by NO species, though its adsorption energy is very small, affects the diffusion of NO on the fcc hollow and atop sites. It is suggested that the activity of NO on the P1(111) can be controlled by the occupation of hcp hollow site by NO.