Preparation and performance of noble metal phosphides supported on silica as new hydrodesulfurization catalysts

Abstract

Preparat ion o f no ble met al (NM) (Rh, Pd, Ru, Pt) phosphide species and t heir cat alyt ic act ivit ies for hydrodesulfur izat ion (HDS) of t hiophene w er e invest igat ed. Noble met al phosphides (NM X P Y) cat alyst s were prepared by reduct ion o f Padded NM (NM-P) support ed on silica (S iO 2) wit h hydrogen. Hydrogen co nsumpt io n peaks at around 350−700 °C, which wer e at t ribut ed t o t he for mat io n o f NM X P Y , were obser ved in t emper at ure-programmed reduct io n (TPR) spect ra of al l NM-P/S iO 2. Furt her more, X-ray diffr act ion (XRD) pat t erns o f NM-P/S iO 2 indicat e t hat NM X P Y (Rh 2 P, Pd 4. 8 P, Ru 2 P, Pt P 2) were for med by hydrogen reduct ion at high t emperat ure. The reduct ion t emperat ure st rongly affect ed HDS act ivit ies o f NM-P/S iO 2 cat alyst s. The NM-P/S iO 2 cat alyst s, ot her t han Pt , showed higher HDS act ivit ies t han NM/S iO 2 cat alyst s. The HDS act ivit y o f t he Rh-P/S iO 2 cat alyst was t he highest amo ng t hose o f NM-P/S iO 2 cat alyst s. This act ivit y was higher than that of the NiP catalyst and was t he same as t hat of pre-sulfided CoMoP/Al 2 O 3 cat alyst. Furt her more, t he Rh-P/S iO 2 cat alyst showed st able act ivit y even aft er react ion for 30 h. The XRD, t ransmiss io n elect ron microscopy (TEM), and energy disper sive X-ray spect roscopy (EDS) result s revealed t hat t he for mat io n o f sma ll Rh 2 P part icles and suit able P addit io n t o for m Rh 2 P caused t he high HDS act ivit y o f t he Rh-P cat alyst .

Preparation of Highly Active Noble Metal Phosphide Catalysts: Effect of Precursors on the Formation of the Active Phase and Hydrodesulfurization Activity

“…Below 150°C, the spectra for the PdP and RhP catalysts contained peaks (the decomposition of Pd hydride and reduction of Rh 2 O 3 ) similar to those in the spectra of the Pd and Rh catalysts, 10 assuming that the peaks observed above 150°C are attributed to the reduction of phosphate. In the spectrum of the PdP(acac) catalyst, H 2 consumption peaks were observed at 295 and 775°C.…”

“…2,1014 We reported that Rh 2 P and Pd 4.8 P showed higher catalytic activity than Ni 2 P and other NM X P Y (Ru and Pt). 10 On the other hand, supported Pt catalysts prepared from acetylacetonato (acac) complexes have higher HDS activity than supported Pt catalysts prepared from other precursors. 15 Thus, it may be possible to prepare highly active NM X P Y catalysts from acac complexes.…”

“…10 Thus, the effect of precursors on the TOF of the NMP catalysts was examined. Assuming that CO adsorbs on NM X P Y (CO/NM = 1), the number of active sites can be estimated based on the CO uptake.…”

“…P-added NM (NMP) catalysts were prepared using a previously described impregnation method. 10,12 The chloride precursors, RhCl 3 ¢3H 2 O and PdCl 2 , were dissolved in water and a 1.0 mol L ¹1 HCl solution, respectively. Ammonium dihydrogenphosphate (NH 4 H 2 PO 4 , AHP) was used for the preparation of NMP(Cl) catalysts.…”

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

“…In particular, nickel phosphide (Ni2P) catalyst, which has high HDS activity, has been widely studied 1) 6) . We previously reported noble metal phosphides supported on SiO2 as a new type of HDS catalyst 7) . The rhodium phosphide (Rh2P) catalyst showed the highest activity among various noble metal phosphides, with equivalent activity to the commercial Co _ Mo catalyst 7) .…”