X-ray diffraction and thermo-analytical investigation of the palladium-phosphorus system

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 .

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“…It was report ed t hat Pd 4 . 8 P deco mposes eut ect oidally int o Pd 6 P and Pd 3 P bet ween 660 °C and 700 °C[31]. This…”

mentioning

confidence: 52%

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

Kanda

Temma

Nakata

et al. 2010

Applied Catalysis A: General

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“…The process of ball-milling and annealing was repeated until the diffraction films showed no trace of lines from neighbouring phases in the Pd-P system, and exhibited only sharp Pd6P lines. Chemical analysis of the final product by the methods described by Gullman (1966) gave the following result: Pd 95.18, P 4.62 wt%, corresponding to a Pd/P atomic ratio of 6/1.000.…”

Section: Molecular Packingmentioning

confidence: 99%

“…The thermodynamics and crystallography of these solid solutions are currently being studied; the solutions in the Pd3P~_ x phase have so far been investigated in some detail (Flanagan, Biehl, Clewley, Rundqvist & Andersson, 1980;Andersson, Rundqvist, Tellgren, Thomas & Flanagan, 1980). The occurrence of the compound Pd6P was first reported by Gullman (1966). The crystal structure was examined by X-ray powder diffraction methods by Andersson, Kaewchansilp, del Rosario C asteleiro Soto & Rundqvist (1974).…”

Section: X-ray Powder Diffractionmentioning

confidence: 99%

Neutron powder diffraction investigation of pure and deuterated palladium phosphide Pd6P

Andersson¹,

Rundqvist²,

Tellgren³

et al. 1981

Acta Crystallogr Sect B

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“…The Pd 4.8 P peaks in the XRD spectra decreased in size and broadened with increasing reduction temperature from 550 to 650°C (Figure 2). Gullman reported that Pd 4.8 P decomposes to Pd 6 P and Pd 3 P. 22 Thus, the decrease in TOF can be explained by the decomposition of Pd 4.8 P. Interestingly, the maximum TOF of the PdP(acac) catalyst was lower than that of the PdP(Cl) catalyst. This trend was also observed for the RhP catalyst.…”

mentioning

confidence: 99%

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

et al. 2013

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The effect of precursors on the active phase formation and hydrodesulfurization activities of noble metal phosphide catalysts was examined. The maximum activities of PdP and RhP catalysts prepared from acetylacetonato (acac) complex were observed at lower reduction temperatures than those for catalysts prepared from chlorides (Cl). The PdP catalyst prepared from acac also showed higher activity than that obtained from Cl. However, this trend was not observed in the RhP catalyst. The characterization results revealed that the higher activity of the PdP catalyst prepared from the acac is due to the highly dispersed Pd 4.8 P.The combustion of organic sulfur compounds in fuels used for boilers and engines results in the formation of sulfur oxides (SO X ). It is well known that SO X causes air pollution, acid rain, and the deactivation of automotive catalysts. Clean fuels are produced by the petroleum industry using hydrodesulfurization (HDS) processes. Recently, the development of new HDS catalysts that exhibit higher activity than commercial CoMo/ Al 2 O 3 catalysts have been claimed to produce cleaner fuels with low sulfur content. 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. In this study, the effect of precursors on the formation of NM X P Y (Pd 4.8 P and Rh 2 P) and its catalytic activity was examined in order to develop a new highly active HDS catalyst.Silica (SiO 2 , 295 m 2 g ¹1 ) was used as the catalyst support. 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. After impregnation, the catalysts were dried at 110°C for 24 h followed by heat treatment at 450°C in N 2 for 1 h to decompose the salts. The sieved catalysts (3042 mesh granules) were calcined in air at 500°C for 4 h (10°C min ¹1 ). The NMP(acac) catalysts were prepared using the same procedure but with acac complexes ([Rh(C 5 H 8 O 2 ) 3 ] and [Pd(C 5 H 7 O 2 ) 2 ]) dissolved in acetylacetone. In addition, triphenylphosphine ((C 6 H 5 ) 3 P, TPP) was used as the P precursor for the preparation of the NMP(acac) catalysts, because AHP does not dissolve in acetylacetone.The HDS of thiophene was performed using a fixed bed flow reactor under atmospheric pressure. The sieved catalyst (0.1 g) was treated in He at 500°C for 1 h, followed by reduction with H 2 at 350700°C for 1 h prior to the reaction. The HDS reaction was carried out using a mixture of H 2 and vaporized thiophene at 0°C, which was introduced into the quartz reactor at 350°C. The W/F of the...

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X-ray diffraction and thermo-analytical investigation of the palladium-phosphorus system

Cited by 48 publications

References 6 publications

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

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

Neutron powder diffraction investigation of pure and deuterated palladium phosphide Pd6P

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

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