Michael Benz, Osman Bunjaku, Michal Nowakowski, Alexander Allgaier, Indro Biswas, Joris van Slageren, Matthias Bauer, Deven P. Estes
{"title":"通过氢化物转移实现氢溢出:氧化锌和二氧化锆与强氢化物供体的反应","authors":"Michael Benz, Osman Bunjaku, Michal Nowakowski, Alexander Allgaier, Indro Biswas, Joris van Slageren, Matthias Bauer, Deven P. Estes","doi":"10.1039/d4cy00504j","DOIUrl":null,"url":null,"abstract":"Hydrogen spillover, transfer of H<small><sub>2</sub></small> from a metal surface to a support (often metal oxides), is pivotal for many heterogeneous catalytic processes, including Cu/ZnO and Cu/ZrO<small><sub>2</sub></small> catalyzed methanol synthesis. Little is known about hydrogen spillover on ZnO or ZrO<small><sub>2</sub></small>, due to the high complexity of the metal–metal oxide interface. Here, we model hydrogen spillover on ZnO and ZrO<small><sub>2</sub></small> by reacting them with molecular metal hydrides to see how the properties of the hydrides affect hydrogen spillover. While the good H· donors HV(CO)<small><sub>4</sub></small>dppe (<strong>1</strong>) and CpCr(CO)<small><sub>3</sub></small>H (<strong>2</strong>) do not react with the metal oxide surfaces, the strong hydride donors <em>i</em>Bu<small><sub>2</sub></small>AlH (<strong>3</strong>), Cp<small><sub>2</sub></small>ZrHCl (<strong>4</strong>), and [HCu(PPh<small><sub>3</sub></small>)]<small><sub>6</sub></small> (<strong>5</strong>) do reduce ZnO and ZrO<small><sub>2</sub></small> to give defect sites with the same EPR signatures as obtained <em>via</em> hydrogen spillover. We also observe new M–O bonds to the surface using X-ray absorption spectroscopy (XAS). We propose that these metal oxides undergo hydrogen spillover <em>via</em> initial hydride transfer followed by tautomerization of the surface hydride, giving reduced sites and OH bonds. This mechanism is in contrast to the traditional spillover mechanism involving discrete proton- and electron transfer steps. We also observe that ZnO is easier to reduce than ZrO<small><sub>2</sub></small>, explaining the difficulty observing spillover on Cu/ZrO<small><sub>2</sub></small>.","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4000,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Hydrogen spillover through hydride transfer: the reaction of ZnO and ZrO2 with strong hydride donors\",\"authors\":\"Michael Benz, Osman Bunjaku, Michal Nowakowski, Alexander Allgaier, Indro Biswas, Joris van Slageren, Matthias Bauer, Deven P. Estes\",\"doi\":\"10.1039/d4cy00504j\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Hydrogen spillover, transfer of H<small><sub>2</sub></small> from a metal surface to a support (often metal oxides), is pivotal for many heterogeneous catalytic processes, including Cu/ZnO and Cu/ZrO<small><sub>2</sub></small> catalyzed methanol synthesis. Little is known about hydrogen spillover on ZnO or ZrO<small><sub>2</sub></small>, due to the high complexity of the metal–metal oxide interface. Here, we model hydrogen spillover on ZnO and ZrO<small><sub>2</sub></small> by reacting them with molecular metal hydrides to see how the properties of the hydrides affect hydrogen spillover. While the good H· donors HV(CO)<small><sub>4</sub></small>dppe (<strong>1</strong>) and CpCr(CO)<small><sub>3</sub></small>H (<strong>2</strong>) do not react with the metal oxide surfaces, the strong hydride donors <em>i</em>Bu<small><sub>2</sub></small>AlH (<strong>3</strong>), Cp<small><sub>2</sub></small>ZrHCl (<strong>4</strong>), and [HCu(PPh<small><sub>3</sub></small>)]<small><sub>6</sub></small> (<strong>5</strong>) do reduce ZnO and ZrO<small><sub>2</sub></small> to give defect sites with the same EPR signatures as obtained <em>via</em> hydrogen spillover. We also observe new M–O bonds to the surface using X-ray absorption spectroscopy (XAS). We propose that these metal oxides undergo hydrogen spillover <em>via</em> initial hydride transfer followed by tautomerization of the surface hydride, giving reduced sites and OH bonds. This mechanism is in contrast to the traditional spillover mechanism involving discrete proton- and electron transfer steps. We also observe that ZnO is easier to reduce than ZrO<small><sub>2</sub></small>, explaining the difficulty observing spillover on Cu/ZrO<small><sub>2</sub></small>.\",\"PeriodicalId\":66,\"journal\":{\"name\":\"Catalysis Science & Technology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.4000,\"publicationDate\":\"2024-08-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Catalysis Science & Technology\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1039/d4cy00504j\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Catalysis Science & Technology","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4cy00504j","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Hydrogen spillover through hydride transfer: the reaction of ZnO and ZrO2 with strong hydride donors
Hydrogen spillover, transfer of H2 from a metal surface to a support (often metal oxides), is pivotal for many heterogeneous catalytic processes, including Cu/ZnO and Cu/ZrO2 catalyzed methanol synthesis. Little is known about hydrogen spillover on ZnO or ZrO2, due to the high complexity of the metal–metal oxide interface. Here, we model hydrogen spillover on ZnO and ZrO2 by reacting them with molecular metal hydrides to see how the properties of the hydrides affect hydrogen spillover. While the good H· donors HV(CO)4dppe (1) and CpCr(CO)3H (2) do not react with the metal oxide surfaces, the strong hydride donors iBu2AlH (3), Cp2ZrHCl (4), and [HCu(PPh3)]6 (5) do reduce ZnO and ZrO2 to give defect sites with the same EPR signatures as obtained via hydrogen spillover. We also observe new M–O bonds to the surface using X-ray absorption spectroscopy (XAS). We propose that these metal oxides undergo hydrogen spillover via initial hydride transfer followed by tautomerization of the surface hydride, giving reduced sites and OH bonds. This mechanism is in contrast to the traditional spillover mechanism involving discrete proton- and electron transfer steps. We also observe that ZnO is easier to reduce than ZrO2, explaining the difficulty observing spillover on Cu/ZrO2.
期刊介绍:
A multidisciplinary journal focusing on cutting edge research across all fundamental science and technological aspects of catalysis.
Editor-in-chief: Bert Weckhuysen
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