Detailed spectroscopic studies of oxygen on metal carbide surfaces

Interaction of oxygen with ZrC(001) and VC(001): Photoemission and first-principles studies

“…5,8,18 However, recent photoemission studies for O / TiC͑001͒ point to the existence of strong oxygen↔ carbon interactions. 21,36 A phenomenon corroborated by the results of first-principles density-functional ͑DF͒ calculations, which predict a CTiTi hollow as the most stable site for the adsorption of O. 36 In contrast, data of high-resolution electron energy loss spectroscopy ͑HREELS͒ for O / VC͑001͒ show the presence of V -O bonds and negligible oxygen↔ carbon interactions.…”

“…[1][2][3][4][5][6][7][8] Traditionally, the oxides have been the compounds with the largest number of technological applications, 1,3,5,[9][10][11][12] but in the last two decades carbides and nitrides are receiving a lot of attention. [6][7][8][13][14][15][16][17][18][19][20][21][22][23][24][25] In broad terms, early transition metal carbides display a unique combination of the physical properties characteristic of noble metals and ceramics. 6,7,25 Many early transition metal carbides are good electrical and thermal conductors while possessing ultrahardness and very high melting points.…”

“…8,[26][27][28][29] In addition, oxygen also affects the performance of metal-carbide coatings used in the fabrication of mechanical and electronic devices. 6,7,21,22 The generation of an oxide film on top of the carbide can lead to a degradation of the conductivity and hardness of the system, 6,7 and oxocarbides can have interesting physical properties on their own. 7,8,22 Several experimental studies have investigated the interaction of oxygen with well-defined surfaces of metal carbides, 21,22,[34][35][36] but the microscopic or atomic details of the oxidation process are not fully understood.…”

“…6,7,21,22 The generation of an oxide film on top of the carbide can lead to a degradation of the conductivity and hardness of the system, 6,7 and oxocarbides can have interesting physical properties on their own. 7,8,22 Several experimental studies have investigated the interaction of oxygen with well-defined surfaces of metal carbides, 21,22,[34][35][36] but the microscopic or atomic details of the oxidation process are not fully understood. A key point is the relative importance of the oxygen↔ metal and oxygen↔ carbon interactions.…”

“…A key point is the relative importance of the oxygen↔ metal and oxygen↔ carbon interactions. 21,22,36 Usually, it is assumed that the C sites of a metal carbide surface play a secondary or minor role in the chemical properties of the system. 5,8,18 However, recent photoemission studies for O / TiC͑001͒ point to the existence of strong oxygen↔ carbon interactions.…”