Access to this article is restricted for 12 months after publication by request of the publisher.. Restriction lift date: 2018-09-27
Spinel-structured ZnCr2O4 with excess Zn is the active ZnO/Cr2O3 catalyst for high-temperature methanol synthesis
| dc.check.date | 2018-09-27 | |
| dc.check.info | Access to this article is restricted for 12 months after publication by request of the publisher. | en |
| dc.contributor.author | Song, Huiqing | |
| dc.contributor.author | Laudenschleger, Daniel | |
| dc.contributor.author | Carey, John J. | |
| dc.contributor.author | Ruland, Holger | |
| dc.contributor.author | Nolan, Michael | |
| dc.contributor.author | Muhler, Martin | |
| dc.contributor.funder | Seventh Framework Programme | en |
| dc.contributor.funder | European Cooperation in Science and Technology | en |
| dc.contributor.funder | Science Foundation Ireland | en |
| dc.date.accessioned | 2017-11-02T09:58:42Z | |
| dc.date.available | 2017-11-02T09:58:42Z | |
| dc.date.issued | 2017-09-27 | |
| dc.date.updated | 2017-11-02T09:49:58Z | |
| dc.description.abstract | A series of ZnO/Cr2O3 catalysts with different Zn:Cr ratios was prepared by coprecipitation at a constant pH of 7 and applied in methanol synthesis at 260–300 °C and 60 bar. The X-ray diffraction (XRD) results showed that the calcined catalysts with ratios from 65:35 to 55:45 consist of ZnCr2O4 spinel with a low degree of crystallinity. For catalysts with Zn:Cr ratios smaller than 1, the formation of chromates was observed in agreement with temperature-programmed reduction results. Raman and XRD results did not provide evidence for the presence of segregated ZnO, indicating the existence of Zn-rich nonstoichiometric Zn–Cr spinel in the calcined catalyst. The catalyst with Zn:Cr = 65:35 exhibits the best performance in methanol synthesis. The Zn:Cr ratio of this catalyst corresponds to that of the Zn4Cr2(OH)12CO3 precursor with hydrotalcite-like structure obtained by coprecipitation, which is converted during calcination into a nonstoichiometric Zn–Cr spinel with an optimum amount of oxygen vacancies resulting in high activity in methanol synthesis. Density functional theory calculations are used to examine the formation of oxygen vacancies and to measure the reducibility of the methanol synthesis catalysts. Doping Cr into bulk and the (10–10) surface of ZnO does not enhance the reducibility of ZnO, confirming that Cr:ZnO cannot be the active phase. The (100) surface of the ZnCr2O4 spinel has a favorable oxygen vacancy formation energy of 1.58 eV. Doping this surface with excess Zn charge-balanced by oxygen vacancies to give a 60% Zn content yields a catalyst composed of an amorphous ZnO layer supported on the spinel with high reducibility, confirming this as the active phase for the methanol synthesis catalyst. | en |
| dc.description.sponsorship | Science Foundation Ireland (SFI funded computational resources at Tyndall and at the Irish Centre for High End Computing (ICHEC)); European Cooperation in Science and Technology (COST action CM1104) | en |
| dc.description.status | Peer reviewed | en |
| dc.description.version | Accepted Version | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.citation | Song, H., Laudenschleger, D., Carey, J. J., Ruland, H., Nolan, M. and Muhler, M. (2017) 'Spinel-Structured ZnCr2O4 with Excess Zn Is the Active ZnO/Cr2O3 Catalyst for High-Temperature Methanol Synthesis', ACS Catalysis, pp. 7610-7622. doi: 10.1021/acscatal.7b01822 | en |
| dc.identifier.doi | 10.1021/acscatal.7b01822 | |
| dc.identifier.endpage | 7622 | en |
| dc.identifier.issn | 2155-5435 | |
| dc.identifier.journaltitle | ACS Catalysis | en |
| dc.identifier.startpage | 7610 | en |
| dc.identifier.uri | https://hdl.handle.net/10468/4945 | |
| dc.identifier.volume | 7 | en |
| dc.language.iso | en | en |
| dc.publisher | American Chemical Society | en |
| dc.relation.project | info:eu-repo/grantAgreement/EC/FP7::SP1::NMP/604296/EU/Catalytic Partial Oxidation of Bio Gas and Reforming of Pyrolysis Oil (Bio Oil) for an Autothermal Synthesis Gas Production and Conversion into Fuels/BIOGO-FOR-PRODUCTION | en |
| dc.rights | © 2017 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/pdf/10.1021/acscatal.7b01822 | en |
| dc.subject | DFT+U | en |
| dc.subject | Methanol synthesis | en |
| dc.subject | Nonstoichiometric spinel | en |
| dc.subject | Oxygen vacancy | en |
| dc.subject | ZnO/Cr2O3 | en |
| dc.title | Spinel-structured ZnCr2O4 with excess Zn is the active ZnO/Cr2O3 catalyst for high-temperature methanol synthesis | en |
| dc.type | Article (peer-reviewed) | en |
