Characterization and HDS Activity of Cobalt Molybdenum Nitrides

Abstract

The characterization of cobalt molybdenum nitrides with various cobalt contents has been studied using XRD, TEM, XPS, and temperature-programmed reactions with NH 3 . The hydrodesulfurization of thiophene on the cobalt molybdenum nitride was carried out using a differential microreactor at atmospheric pressure. The XRD analysis of Co( 50)973 indicated that Co 3 Mo 3 N was formed from the nitriding of a CoMoO 4 precursor prepared from Co(NO 3 ) 2 ‚6H 2 O and (NH 4 ) 6 Mo 7 O 24 ‚4H 2 O but not from the mixture of CoO and MoO 3 . Co-(10-25)973 had a high surface area of 120-129 m 2 g -1 , but Co(50)973 had that of 12 m 2 g -1 . The BET surface area was related to the molybdenum ions (Mo 2+ and Mo 3+ ) and cobalt ion (Co 3+ ) in the bulk sample. The XPS and elemental analyses of Co(50)973 showed that the bulk composition was Co 3 Mo 3 N‚N 0.2 and the surface composition was Co 3 Mo 3 N‚N 2 . The cobalt molybdenum nitride Co(0-35)973 was more active than cobalt molybdenum sulfide on basis of catalyst weight in the hydrodesulfurization of thiophene at 623 K.

On the surface sites of MoP/SiO2 catalyst under sulfiding conditions: IR spectroscopy and catalytic reactivity studies

“…Among the explored catalysts, transition metals modified by main group elements other than sulfur have attracted much attention as they were consid-ered to be potential catalytic materials to substitute for conventional sulfide catalysts. Since the 1980s, transition metal nitride and carbide catalysts have been extensively studied and were found to have superior activities to traditional Mo sulfide catalysts in hydrotreating processes (both hydrodesulfurization (HDS) and hydrodenitrogenation (HDN)) [2][3][4][5]. More recently, transition metal phosphides prepared by temperature-programmed reduction (TPR) were reported to have high catalytic activity for both HDN [6][7][8][9][10][11][12][13][14][15][16][17][18] and HDS [10][11][12][13][14][15][16][17]19,20].…”

コバルト・モリブデン窒化触媒のジベンゾチオフェンの水素化脱硫反応における触媒活性点分布―ノンパラメトリック研究―

“…The Co atom of the nitrided CoMo/Al2O3 catalyst might not play an important role in dibenzothiophene HDS. In a previous paper 19) , cobalt species penetrated into the bulk and increased the surface area of γ-Mo2N. Also, the highly active 973 K-nitrided bulk CoMo catalyst had a slightly reduced Mo nitride containing Mo 0 and Mo 2 .…”

“…The valence distributions of the XPS Mo spectrum of the catalyst before reaction are shown in Table 4. The Mo 19) , the total distribution of Mo 0 and Mo 2 was reported to be 70 % for bulk Co(30 %)Mo(65 %) nitrided at 973 K. As a result, the nitridation hardly reduced Mo oxides of aluminasupported Co(4 %)Mo(12 %) catalyst to metals or nitrides.…”

Syntesis by reactive grinding of molibdenum iron bimetallic nitride

“…Así, se les ha encontrado utilidad como materiales estructurales, como herramientas de corte, o como catalizadores, entre otras. En particular, el nitruro de molibdeno, además de las propiedades antes mencionadas, fue propuesto en 1981 como un compuesto superconductor [8][9] y, recientemente, ha sido mostrado en la bibliografía como poseedor de una alta actividad catalítica [10][11][12][13][14][15][16][17][18][19] .Por otra parte, el estudio de los nitruros ternarios de los metales de transición, empezó a cobrar relevancia a partir de 1993, cuando se publicó la obtención del FeWN 2 [20] , ya que estos compuestos poseen propiedades comparables o incluso superiores a las de los nitruros binarios. No obstante, si el conocimiento de las propiedades fisicoquímicas y de las estructuras de los nitruros binarios dista mucho de ser completo, con respecto a los nitruros ternarios apenas si existen algunos estudios.…”

“…No obstante, si el conocimiento de las propiedades fisicoquímicas y de las estructuras de los nitruros binarios dista mucho de ser completo, con respecto a los nitruros ternarios apenas si existen algunos estudios. A pesar del gran potencial tecnológico sólo un pequeño número de compuestos están identificados hoy en día.Las rutas de síntesis más utilizadas para este tipo de nitruros son: amonolisis del óxido mixto, como es el caso del Co 3 Mo 3 N, a partir de CoMoO 4 ; ó, a partir de mezclas de óxidos, como el caso del Ni 2 Mo 3 N, a partir de NiMoO 4 y MoO 3 [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] . Otra ruta utilizada ha sido la reacción entre el nitruro de molibdeno y el metal [27] , por amonolisis del nitrato del metal soportado en el nitruro de molibdeno [12] y, por último, amonolisis de una mezcla de los cloruros metálicos [28] .…”