Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 143
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3098
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Severity: Warning
Message: Attempt to read property "Count" on bool
Filename: helpers/my_audit_helper.php
Line Number: 3100
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3100
Function: _error_handler
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
ZnO/ZrO catalysts have shown better activity in the CO hydrogenation to methanol compared with single component counterparts, but the interaction between ZnO and ZrO is still poorly understood. In particular, the effect of the ZrO support phase (tetragonal vs. monoclinic) was not systematically explored. Here, we have synthesized ZnO/ZrO catalysts supported on tetragonal ZrO (ZnO/ZrO-t) and monoclinic ZrO (ZnO/ZrO-m), which resulted in the formation of different ZnO species, consisting of sub-nanometer ZnO moieties and large-sized ZnO particles, respectively. ZnO/ZrO-t exhibited a higher methanol selectivity (81 vs. 39 %) and methanol yield (1.25 vs. 0.67 mmol g h) compared with ZnO/ZrO-m. The difference in performance was attributed to the redox state and degree of dispersion of Zn, based on spectroscopy and microscopy results. ZnO/ZrO-t had a high density of ZnO-ZrO sites, which favored the formation of active HCOO* species and enhanced the yield and selectivity of methanol along the formate pathway. Such ZnO clusters were further dispersed on ZrO-t during catalysis, while larger ZnO particles on ZnO/ZrO-m remained stable throughout the reaction. This study shows that the phase of ZrO supports can be used to control the dispersion of ZnO and the catalyst surface chemistry, and lead to enhanced catalytic performance.
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Source |
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http://dx.doi.org/10.1002/anie.202416899 | DOI Listing |
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