New VIII group metal alloy catalysts - preparation and catalytic functions

Pd supported on ZnO, Ga - D22 - D2O - D23 - D2, In - D22 - D2O - D23 - D2, or CdO, Pt supported on ZnO，Ga - D22 - D2O - D23 - D2, or In - D22 - D2O - D23 - D2or Ru supported on In i D22 i D2O i D23 i D2 exhibited anomalously high selectivity for (a)dehydrogenation of CH D23 D2OH to HCOOCH D23 D23 D2 and (b) of CH D23 D2CH D22 D2OH toCH - D23 D2COOC D22 D2H D25 - D2, c the steam reforming of methanol，and (d) hydrogenolysis of ester (HCOOCH - D23 - D2 or CH - D23 - D2COOC - D22 - D2H - D25 - D2) to alcohol（CH D23 D2OH and CH D23 D2CH D2OH） among various supported VIII group metal catalysts.selectivity for The reaction (a), (b)c或(d) was greatly improved upon the formation of bimetallic alloys (Pd-Zn, Pd-Ga, Pd-Ga, Pt-Zn，pt-ga,and Pt-In). Over the alloyed catalysts aldehyde species (HCHO or CH D23 D2CHO) formed in thereactions were stabilized, and (1) effectively attacked by CH D23 D2O- (or，D23 D2CH D22 D2O-), -OH and hydrogen, being transformed into HCOOCH D23 D2…More (or CH - D23 - D2COOC - D22 - D2H - D25 - D2) and CO - D22 - D2/H - D22 - D2 respectively in thedehydrogenation of CH D23 D2OH or CH D23 D2CH D22 D2OH and the steam reforming ofD2OH or (2) attacked by hydrogen，being selectively converted into CH D23 D2OH (or CH D23 D2CH D22 D2OH) in the hydrogenolysisof HCOOCH D23 - D2 (or CH D23 - D2COOC - D22 - D2H - D25 - D2). Over the other catalysts containingunalloyed Pd or Pt，HCHO or chi D23 chi D2CHO species were readily decarbonylated to CO chi D22 - D2/ chi D22 - D2 orCO/CH D24 D2 in dehydrogenation of CH D23 D2 or CH D23 D2CH D22 D2OH，steam reforming of CH D23 D2OH and hydrogenolysis of HCOOCH D23 D2 orD22 D2H D2H D25 D2.Mechanism of the Pd-Zn alloy formation was also studied in thePd/ZnO catalysts.这是发现hydrogen initially retained in Pd spilled rapidlyover to ZnO. The ZnO was then reduced to metallic Znbeing transformed into PdZn. Once the alloy producedhydrogen atoms on the alloys to ZnO was greatly suppressed，resulting in the selective formation of PdZn in the course of the reduction of Pd/ZnO. Less

Pd supported on ZnO, GaィイD22ィエD2OィイD23ィエD2, InィイD22ィエD2OィイD23ィエD2, or CdO, Pt supported on ZnO, GaィイD22ィエD2OィイD23ィエD2, or InィイD22ィエD2OィイD23ィエD2, or Ru supported on InィイD22ィエD2OィイD23ィエD2 exhibited anomalously high selectivity for (a) dehydrogenation of CHィイD23ィエD2OH to HCOOCHィイD23ィエD2 and (b) of CHィイD23ィエD2CHィイD22ィエD2OH to CHィイD23ィエD2COOCィイD22ィエD2HィイD25ィエD2, c the steam reforming of methanol, and (d) hydrogenolysis of ester (HCOOCHィイD23ィエD2 or CHィイD23ィエD2COOCィイD22ィエD2HィイD25ィエD2) to alcohol (CHィイD23ィエD2OH and CHィイD23ィエD2CHィイD22ィエD2OH ) among various supported VIII group metal catalysts. The selectivity for the reaction (a), (b), c or (d) was greatly improved upon the formation of bimetallic alloys (Pd-Zn, Pd-Ga, Pd-Ga, Pt-Zn, Pt-Ga, and Pt-In ). Over the alloyed catalysts aldehyde species (HCHO or CHィイD23ィエD2CHO) formed in the reactions were stabilized, and (1) effectively attacked by CHィイD23ィエD2O- (or, CHィイD23ィエD2CHィイD22ィエD2O-) , -OH and hydrogen, being transformed into HCOOCHィイD23ィエD2 … More (or CHィイD23ィエD2COOCィイD22ィエD2HィイD25ィエD2) and COィイD22ィエD2/HィイD22ィエD2 respectively in the dehydrogenation of CHィイD23ィエD2OH (or CHィイD23ィエD2CHィイD22ィエD2OH ) and the steam reforming of CHィイD23ィエD2OH or (2) attacked by hydrogen, being selectively converted into CHィイD23ィエD2OH ( or CHィイD23ィエD2CHィイD22ィエD2OH ) in the hydrogenolysis of HCOOCHィイD23ィエD2 (or CHィイD23ィエD2COOCィイD22ィエD2HィイD25ィエD2). Over the other catalysts containing unalloyed Pd or Pt, HCHO or CHィイD23ィエD2CHO species were readily decarbonylated to COィイD22ィエD2/HィイD22ィエD2 or CO/CHィイD24ィエD2 in dehydrogenation of CHィイD23ィエD2 or CHィイD23ィエD2CHィイD22ィエD2OH, steam reforming of CHィイD23ィエD2OH and hydrogenolysis of HCOOCHィイD23ィエD2 or CHィイD23ィエD2COOCィイD22ィエD2HィイD25ィエD2.Mechanism of the Pd-Zn alloy formation was also studied in the reduction of Pd/ZnO catalysts. It was found that hydrogen initially retained in Pd spilled rapidly over to ZnO. The ZnO was then reduced to metallic Zn, being transformed into PdZn. Once the alloy produced, the spillover hydrogen atoms on the alloys to ZnO was greatly suppressed, resulting in the selective formation of PdZn in the course of the reduction of Pd/ZnO. Less