Formation of active sites and hydrodesulfurization activity of rhodium phosphide catalyst: Effect of reduction temperature and phosphorus loading

Abstract

The Rh-1.5P catalyst exhibited the highest activity among the investigated catalysts. ► Rh2P was easily formed in catalysts with a higher P loading. ► Higher P loadings and higher reduction temperatures led to aggregation of Rh species. ► RhP2 exhibits lower catalytic activity than Rh2P. ► High HDS activity was caused by small Rh2P formation at lower reduction temperature.

Formation of Rh₂P Supported on Na-form Zeolites and Catalytic Activity for Hydrodesulfurization

“…The main HDS products of the Rh _ P/NaMFI catalyst were butanes, butenes, tetrahydrothiophene (THT) and cracking products (C1-C3). This trend was similar with the HDS products of Rh _ P/SiO2 catalyst 13) at the same thiophene conversion (10.4 %). On the other hand, trace amount of 1,3-butadiene was produced over the Rh _ P/NaMFI and Rh _ P/NaBEA catalysts, and trace amount of 2-methylthiophene was produced over the Rh _ P/NaBEA catalyst.…”

“…Therefore, the phosphates easily formed enlarged particles on the external surface. Reduction of large phosphate particles was facilitated because of the weak interaction between the phosphates and the support 13) . On the basis of these results, the maximum peak of phosphate reduction in the Rh _ P/NaMOR catalyst was observed at the lowest temperature among the Rh _ P/zeolite catalysts.…”

“…Dispersion of Rh species and phosphates may be changed by the micropore structure of zeolites. We previously found that large phosphate particles are easy to reduce 13) . Therefore, formation temperature and dispersion of Rh2P affect the catalytic activity.…”

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

“…Kanda et al [6,29] applied the incipient wetness impregnation method for the preparation of Ru 2 P, PtP 2 , Rh 2 P, and Pd 4.8 P on SiO 2 to test the metal phosphides as catalysts in the HDS of thiophen. On later publications, Kanda et al [30] focused on the preparation of Rh 2 P on different support materials (SiO 2 , TiO 2 , Al 2 O 3 , MgO, and ZrO 2 ) and the effect of the reduction temperature and the effect of phosphorus loading [31] on the formation of Rh 2 P. The compound Rh 2 P can be successfully prepared on all the support materials investigated. Further, Kanda observed the formation of Rh 2 P on SiO 2 at lower reduction temperatures (350 • C) with a high excess of phosphorus (P:Rh = 2), while higher temperatures are required (550 • C) to form phase-pure Rh 2 P on SiO 2 samples with a lower excess of phosphorus (P:Rh = 1).…”

“…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].…”