Noble Metal Phosphides as New Hydrotreating Catalysts: Highly Active Rhodium Phosphide Catalyst

Abstract

Metal phosphide has been widely investigated as a hydrotreating catalyst. The preparation and performance of noble metal phosphide catalyst was examined to develop new phosphide hydrotreating catalysts. The supports affect reducibility of phosphate as a P precursor. Since phosphate does not strongly interact with SiO2 and TiO2 supports, Rh2P was easily formed on these supports. Furthermore, formation of Rh2P enhanced the hydrodesulfurization (HDS) activity of supported Rh _ P catalyst. The type of noble metal (NM) and P/NM ratio also strongly affect formation of noble metal phosphide and HDS activity. Excess P facilitates formation of noble metal phosphides at lower reduction temperature. In contrast, excess P causes the aggregation of noble metal phosphide and formation of phosphorus rich noble metal phosphide. Rh _ 1.5P/SiO2 catalyst had high and stable activity for HDS reaction. Furthermore, this catalyst showed significantly higher hydrodenitrogenation (HDN) activity than sulfided NiMoP/Al2O3 catalyst. Therefore, Rh2P has great potential as a new hydrotreating catalyst.

Low-temperature synthesis of rhodium phosphide on alumina and investigation of its catalytic activity toward the hydrodesulfurization of thiophene

“…New active phases, especiall y nickel phosphide (Ni2P), have received extensive attention . Furthermore, our group [23][24][25][26][27] and Bussell's group [3,28] reported that rhodium phosphide (Rh 2 P) supported on SiO2 exhibits high and stable catal ytic activit y toward the HDS reaction.…”

Platinum Group Metal Phosphides as Efficient Catalysts in Hydroprocessing and Syngas-Related Catalysis

“…The development of the noble metal phosphide catalysts for hydrotreating catalysts shows that Rh 2 P displays the highest activity in the HDS and HDO reactions. The main factors affecting the activity of Rh 2 P are the preparation pathway and precursors, reduction temperature, and support material as shown by the broad investigations by Kanda et al [29][30][31][32][33][34]43,52]. For deoxygenation reactions, cooperative mechanisms of multifunctional or adjacent sites are discussed as a major motive.…”

“…Further investigations have shown that Rh 2 P has a higher activity in the HDS of thiophene than all the other PGM phosphides [29]. Due to the higher intrinsic activity of the Rh 2 P catalyst, different publications have focused on the application of Rh 2 P as a catalyst material for hydrotreating reactions [27][28][29][30][31][32][33][34]43,47,52], for the hydrogen evolution reaction [53], and for the hydroformylation [35]. Reviews focusing on the metal phosphides in general and their applications as catalyst materials can be found elsewhere [24][25][26]49,54,55].…”

“…The investigations performed by Kanda and Sawanda and other research groups on the performance of supported Rh 2 P catalysts and other supported noble metal phosphides as hydrotreating catalysts were reviewed in 2015 by Kanda and Uemichi [52].…”

Catalytic Activity of Rhodium Phosphide for Selective Hydrodeoxygenation of Phenol

“…We reported the effect of reduction temperature and P/Rh ratio on HDS activity of P-added Rh (Rh-P) catalyst. 10,11 Different optimal reduction temperature and P/Rh ratio for HDO activity of Rh-P catalyst would be observed in addition to HDS activity.…”