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Peroxo-heteropoly compound PO 4 [W(O)(O 2 ) 2 ] was synthesized on calcium-deficient hydroxyapatite using a reaction of surface [HPO 4 ] 2- groups on hydroxyapatite with a Na 2 [W 2 O 3 (O 2 ) 4 ] aqueous solution. The vibration of [HPO 4 ] 2- at 875 cm -1 became very weak, and the vibration of the peroxo-oxygen bond [O-O] 2- at 845 cm -1 appeared in the FT-IR spectrum of the solid product, indicating that PO 4 [W(O)(O 2 ) 2 ] was formed on the surface of hydroxyapatite. The formed solid sample was further reacted with PdCl 2 (PhCN) 2 in an acetone solution to fix PdCl 2 between the O sites on the hydroxyapatite. Elemental analyses proved that the resultant solid contained 1.2 wt.% Pd, implying that PdCl 2 molecules were immobilized on the surface of hydroxyapatite. The hydroxyapatite-based hybrid compound containing Pd and PO 4 [W(O)(O 2 ) 2 ] was used as a heterogeneous catalyst in a methanol solvent for propylene epoxidation by molecular oxygen in an autoclave batch reaction system. A propylene conversion of 53.4% and a selectivity for propylene oxide of 88.7% were obtained over the solid catalyst after reaction at 363 K for 8 h. The novel catalyst could be reused by a simple centrifugal separation, and the yield of propylene oxide did not decrease after the reaction for five runs. By prolonging the reaction time to 13 h, the highest yield of propylene oxide at 363 K over the solid catalyst was obtained as 53.8%, which was almost the same as that of the homogeneous catalyst containing PdCl 2 (PhCN) 2 and [(C 6 H 13 ) 4 N] 2 {HPO 4 [W(O)(O 2 ) 2 ] 2 } for the propylene epoxidation. Methanol was used as a solvent as well as a reducing agent in the propylene epoxidation by molecular oxygen. Small particles of Pd metal were formed on the surface of the hybrid solid catalyst during the reaction, and acted as active species to achieve the catalytic turnover of PO 4 [W(O)(O 2 ) 2 ] in the propylene epoxidation by molecular oxygen in methanol.

A kind of composite material PdZnAl(HT)/MCM-48 was synthesized by dispersing PdZnAl-type hydrotalcite (denoted as PdZnAl(HT)) on mesoporous silica MCM-48. PdZnAl(HT) was confirmed to be formed on the MCM-48 in small particles, and the small PdZnAl(HT) particles easily collapsed during increasing the temperature. A kind of novel PdZn(Al)O/MCM-48 catalyst was obtained after calcining and reducing the PdZnAl(HT)/MCM-48 precursor. PdZn alloy species were formed on the PdZnAl(HT)/MCM-48 after reducing in H 2 at 673 K. PdZn(Al)O/MCM-48-2 (with a mass ratio of PdZn(Al)O to MCM-48 = 1) had a large BET surface area (431 cm2 g−1) and small size of PdZn particles (4.1 nm) at the same time. In the steam reforming of methanol, the catalytic stability of PdZn(Al)O/MCM-48-2 was much higher than that of the Cu-based catalyst CuZn(Al)O at 503 K. The methanol conversion over PdZn(Al)O/MCM-48-2 greatly increased with increasing reaction temperature and reached 99% at 513 K. PdZn(Al)O/MCM-48-2 showed higher catalytic activity than PdZnAl(HT) and PdZn/MCM-48 (imp) at the same reaction temperature. The initial CO 2 selectivity and H 2 selectivity over PdZn(Al)O/MCM-48-2 at 503 K were 99.6 and 99.4%, respectively. Moreover, PdZn(Al)O/MCM-48-2 showed the highest rate of H 2 production among various catalysts in the steam reforming of methanol. In a long-time operation, the methanol conversion over PdZn(Al)O/MCM-48-2 decreased from 75.8 to 68.5% after 50 h on stream at 503 K. The size of PdZn particles did not increase after 50 h on stream but the carbonaceous deposits on the catalyst surface caused the deactivation. The deactivated catalyst could be regenerated by calcining in the air at 723 K followed by reducing in the H 2 at 673 K. The carbonaceous deposits were eliminated by calcining in the air and the PdZn active species were formed again by reducing in H 2. • PdZnAl-type hydrotalcite was synthesized on MCM-48 to form PdZnAl(HT)/MCM-48. • PdZn(Al)O/MCM-48 derived from PdZnAl(HT)/MCM-48 had small metal particles. • PdZn(Al)O/MCM-48 showed high activity and stability for methanol steam reforming. • Carbonaceous deposits caused the catalyst deactivation in long-time operation. • The used catalyst was regenerated by calcining in air and then reducing in H 2. [ABSTRACT FROM AUTHOR]

Peroxo-heteropoly compound PO4[W(O)(O2)2] was synthesized on calcium-deficient hydroxyapatite using a reaction of surface [HPO4]2− groups on hydroxyapatite with a Na2[W2O3(O2)4] aqueous solution. The vibration of [HPO4]2− at 875 cm−1 became very weak, and the vibration of the peroxo-oxygen bond [O–O]2− at 845 cm−1 appeared in the FT-IR spectrum of the solid product, indicating that PO4[W(O)(O2)2] was formed on the surface of hydroxyapatite. The formed solid sample was further reacted with PdCl2(PhCN)2 in an acetone solution to fix PdCl2 between the O sites on the hydroxyapatite. Elemental analyses proved that the resultant solid contained 1.2 wt.% Pd, implying that PdCl2 molecules were immobilized on the surface of hydroxyapatite. The hydroxyapatite-based hybrid compound containing Pd and PO4[W(O)(O2)2] was used as a heterogeneous catalyst in a methanol solvent for propylene epoxidation by molecular oxygen in an autoclave batch reaction system. A propylene conversion of 53.4% and a selectivity for propylene oxide of 88.7% were obtained over the solid catalyst after reaction at 363 K for 8 h. The novel catalyst could be reused by a simple centrifugal separation, and the yield of propylene oxide did not decrease after the reaction for five runs. By prolonging the reaction time to 13 h, the highest yield of propylene oxide at 363 K over the solid catalyst was obtained as 53.8%, which was almost the same as that of the homogeneous catalyst containing PdCl2(PhCN)2 and [(C6H13)4N]2{HPO4[W(O)(O2)2]2} for the propylene epoxidation. Methanol was used as a solvent as well as a reducing agent in the propylene epoxidation by molecular oxygen. Small particles of Pd metal were formed on the surface of the hybrid solid catalyst during the reaction, and acted as active species to achieve the catalytic turnover of PO4[W(O)(O2)2] in the propylene epoxidation by molecular oxygen in methanol. [ABSTRACT FROM AUTHOR]

Abstract: An indirect route containing methanol dehydrogenation, DME carbonylation, and methyl acetate hydrogenolysis was used for ethanol synthesis from methanol and syngas. DME was produced stably from the methanol dehydrogenation with a 90% yield over H-ZSM-5 at 453K under 1MPa. A cold trap was set behind the methanol dehydrogenation to collect the formed water and unreacted methanol. Rh/Cs2H2SiW12O40 was an excellent catalyst for the DME carbonylation to methyl acetate at 473K. The selectivity for methyl acetate was very high (>90%) and raising CO/DME ratio improved the DME conversion. A reaction intermediate similar to the homogeneous Rh-I system could be formed on the Rh/Cs2H2SiW12O40 surface. Cu/CeO2 was an excellent catalyst for the methyl acetate hydrogenolysis to methanol and ethanol at 523K. Both active Cu0 species and active Cu+ species could be stabilized in the Cu/CeO2 catalyst. When three fixed-bed reactors and one cold trap were linked together to achieve the ethanol synthesis from methanol and syngas, an ethanol selectivity of 91.1% was obtained at a methanol conversion of 47.2% under 1MPa. [Copyright &y& Elsevier]

Abstract: A new type of layered double hydroxides intercalated by peroxo-polyoxometalates was synthesized by treating PdMAl-[PW11O39] (M = Mg2+ or Zn2+) with 30% H2O2. XRD, FT-IR, and 31P MAS NMR revealed that the interlayer anion [PW11O39]7− was converted mainly to {PO4[WO(O2)2]4}3− and [W2O3(O2)4(H2O)2]2−. 27Al MAS NMR revealed that the brucite-like layers did not collapse during synthesis. PdMgAl-[PW4 + W2] showed 91.5% selectivity for propene oxide at 47.5% conversion during propene epoxidation by O2 in methanol at 353 K for 10 h. The catalytic ability of PdMgAl-[PW4 + W2] can be attributed to the presence of highly active Pd particles in the brucite-like layers that generate H2O2 in situ, the strong epoxidation ability of interlayer peroxo-polyoxometalates with dilute H2O2, and the promotion effect of the basic MgAl-type brucite-like layers toward alkene epoxidation. Moreover, PdMgAl-[PW4 + W2] can be separated and reused by filtration without leaching active components into the solvent. [Copyright &y& Elsevier]

The Pd(OAc)2/Ti—Al-HMS/CH3OH catalyst system showed 61.2% selectivity for PO at 42.8% propylene conversion for the oxidation of propylene with molecular oxygen in an autoclave reactor at 373 K for 4 h. The catalyst is reusable using the filtration method or the vacuum distillation method after reaction. It is likely that a Ti cyclic peracid-like intermediate was formed in the system made up of a Ti site, an oxygen molecule and a methanol molecule. The Pd species activates the oxygen molecule and the Al site plays a role for stabilizing the Ti cyclic peracid-like intermediate to improve the yield of propylene oxide from the oxidation of propylene with molecular oxygen. [ABSTRACT FROM AUTHOR]

The catalyst system consisting of Pd, Ti-modified MCM-22, and methanol was found to catalyze the epoxidation of propylene with molecular oxygen without hydrogen and PO was formed with a PO yield above 19.5% and 458 turnovers based on palladium. The catalyst performance of Pd is affected by the properties of Ti-modified MCM-22 such as BET surface area and the amount of NH3 adsorption. The catalyst material consisting of palladium and Ti-modified MCM-22 can be recovered and used 3 times without reduction in the PO yield. It is assumed that not only palladium but also peroxy intermediates derived from methanol/oxygen play an important role in the oxidation of propylene. [Copyright &y& Elsevier]

A series of Ce1-xCuxO2-δ mixed oxides were synthesized using a co-precipitation method and tested as catalysts for the steam reforming of methanol. XRD patterns of the Ce1-xCuxO2-δ mixed oxides indicated that Cu2+ ions were dissolved in CeO2 lattices to form a solid solution by calcination at 773K when x < 0.2. A TPR (temperature-programmed reduction) investigation showed that the CeO2 promotes the reduction of the Cu2+ species. Two reduction peaks were observed in the TPR profiles, which suggested that there were two different Cu2+ species in the Ce1-xCuxO2-δ mixed oxides. The TPR peak at low temperature is attributed to the bulk Cu2+ species which dissolved into the CeO2 lattices, and the peak at high temperature is due to the CuO species dispersed on the surface of CeO2. The Ce1-xCuxO2-δ mixed oxides were reduced to form Cu/CeO2 catalysts for steam reforming of methanol, and were compared with Cu/ZnO, Cu/Zn(Al)O and Cu/AL2O3 catalysts. All the Cu-containing catalysts tested in this study showed high selectivities to CO2 (over 97%) and H2. A 3.8wt% Cu/CeO2 catalyst showed a conversion of 53.9% for the steam reforming of methanol at 513K (W/F = 4.9 g h mol-1), which was higher than that over Cu/ZnO (37.9%), Cu/Zn(Al)O (32.3%) and Cu/AL2O3 (11.2%) with the same Cu loading under the same reaction conditions. It is likely that the high activity of the Cu/CeO2 catalysts may be due to the highly dispersed Cu metal particles and the strong metalsupport interaction between the Cu metal and CeO2 support. Slow deactivations were observed over the 3.8wt% Cu/CeO2 catalyst at 493 and 513K. The activity of the deactivated catalysts can be regenerated by calcination in air at 773K followed by reduction in H2 at 673K, which indicated that a carbonaceous deposit on the catalyst surface caused the catalyst deactivation. Using the TPO (temperature-programmed oxidation) method, the amounts of coke on the 3.8wt% Cu/CeO2 catalyst were 0.8wt% at 493K and 1.7wt% at 513K after 24h on stream. [ABSTRACT FROM AUTHOR]

The Ce1−xCuxO2−x mixed oxides were synthesized using the coprecipitation method. The X-ray diffraction (XRD) patterns and the temperature-programmed reduction (TPR) profiles indicated that the Cu2+-ions were dissolved into the CeO2 lattices to form a solid solution by calcination at 723 K when x<0.2 in the Ce1−xCuxO2−x mixed oxides. The Ce1−xCuxO2−x mixed oxides were reduced to form the Cu/CeO2 (cop) catalysts for the steam reforming of methanol. The activity and selectivity of Cu/CeO2 (cop) were compared with those of Cu/ZnO, Cu/Zn(Al)O and Cu/Al2O3. All the Cu-containing catalysts tested in this study showed high selectivities to CO2 (over 97%) and H2. A 3.9 wt.% Cu/CeO2 (cop) catalyst showed a conversion of 53.9% for the steam reforming of methanol at 513 K, which was higher than the conversions over Cu/ZnO (37.9%), Cu/Zn(Al)O (32.3%) and Cu/Al2O3 (11.2%) with the same Cu loading under the same reaction conditions. The high activity of the 3.9 wt.% Cu/CeO2 (cop) catalyst may be due to the highly dispersed Cu metal particles and the Cu+ species stabilized by the CeO2 support. Slow deactivation was observed over the 3.9 wt.% Cu/CeO2 (cop) catalyst at 493 and 513 K. The activity of the deactivated catalysts can be regenerated by calcination in air at 723 K, followed by reduction in H2 at 673 K. Such success indicated that the carbonaceous deposit on the catalysts surface caused the catalysts’ deactivation. The temperature-programmed oxidation (TPO) method indicated that the amounts of coke on the 3.9 wt.% Cu/CeO2 (cop) catalyst were 0.8 wt.% at 493 K and 1.7 wt.% at 513 K after 24 h on stream. [Copyright &y& Elsevier]

Peroxo-polyoxometalates pillared hydrotalcite has been synthesized by decomposing [PW11O39]7- pillared MgPdAl-type hydrotalcite with 30% H2O2; the novel heterogeneous catalyst showed 91.5% selectivity for propylene oxide at 47.5% propylene conversion for propylene epoxidation by O2 in methanol at 353 K for 10 h. [ABSTRACT FROM AUTHOR]

• A combined CO 2 capture and reduction process to methanol was developed and tested. • Addition of Na/Al 2 O 3 increased CCR performance to methanol. • A sequential configuration of Na/Al 2 O 3 with Cu/ZnO/Al 2 O 3 was optimal. • Higher pressures increased CO 2 capture performance and methanol selectivity. Recently, carbon capture and reduction (CCR) technology has gained interest to directly convert CO 2 to value-added products without requiring purification of CO 2 and its subsequent transportation. CCR to methanol in one dual function material (DFM) poses mechanistic and kinetic challenges. To counteract this, a process combining Na/Al 2 O 3 as a capture component and Cu/ZnO/Al 2 O 3 (CZA) as methanol synthesis catalyst was developed to allow CCR to methanol. With a 5 vol% CO 2 flow for capture and subsequent H 2 stream combined with a temperature swing, a methanol selectivity of 26 % was achieved at 9 bar. Further investigation found that Na/Al 2 O 3 significantly increased methanol yield, while a stacked configuration of Na/Al 2 O 3 followed by CZA significantly outperformed a mixed configuration of the two catalysts. With further investigation of operation at higher pressure and surface mechanism, an effective CCR to methanol process using two affordable yet readily available catalysts can be realized. [ABSTRACT FROM AUTHOR]