The role of metal-support interactions in sintering and themal deactivation of HDS/HDN catalysts

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The sintering process in CoO-MoO₃/Al₂O₃ and NiO-MoO₃/Al₂O₃ catalysts for HDS/HDN has been studied using two industrial catalysts and their model systems, subjected to thermal treatment in Qxidizingand reducing atmospheres. The critical role of oxidizing atmosphere for rapid sintering has been found to be connected with the formation of free MoO₃ phase, distinguished by high mobility in lower temperature regime and intermediary presence of liquid phase at higher temperatures. A prerequisite for HDS/HDN catalyst sintering during regeneration is the destruction of active monolayer structure that results in formation of the precursor of MoO₃ phase. Specific role of metal-support interactions in this deactivation mechanism has been shown by comparative investigation on model systems prepared on more inert supports (<i style="mso-bidi-font-style:normal"><span style="font-size: 11.0pt;line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:="" minor-latin;mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:="" minor-fareast;mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">ɑ</span></i><span style="font-size:11.0pt;line-height:115%;font-family:" calibri","sans-serif";="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"times="" new="" roman";="" mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:minor-latin;="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">-Al₂O₃ and SiO₂).</span></span>