Search Results

You searched for all publications:

with publication states 'Published (Approved)'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

2 items found (0 items not approved), displaying all items.1

Instruments / Technical Area	Publication Details	Published	Actions
B18-Core EXAFS	Support and gas environment effects on the preferential oxidation of carbon monoxide over CO3O4 catalysts studied in situ Thulani M. Nyathi , Mohamed I. Fadlalla , Nico Fischer , Andrew P. E. York , Ezra J. Olivier , Emma K. Gibson , Peter P. Wells , Michael Claeys Applied Catalysis B: Environmental 5 DOI: 10.1016/j.apcatb.2021.120450 Diamond Proposal Number(s): [19850] Show Abstract ▼ Abstract: We have studied the effect of different supports (CeO2, ZrO2, SiC, SiO2 and Al2O3) on the catalytic performance and phase stability of Co3O4 nanoparticles during the preferential oxidation of CO (CO-PrOx) under different H2-rich gas environments and temperatures. Our results show that Co3O4/ZrO2 has superior CO oxidation activity, but transforms to Co0 and consequently forms CH4 at relatively low temperatures. The least reduced and least methanation active catalyst (Co3O4/Al2O3) also exhibits the lowest CO oxidation activity. Co-feeding H2O and CO2 suppresses CO oxidation over Co3O4/ZrO2 and Co3O4/SiC, but also suppresses Co0 and CH4 formation. In conclusion, weak nanoparticle-support interactions (as in Co3O4/ZrO2) favour high CO oxidation activity possibly via the Mars-van Krevelen mechanism. However, stronger interactions (as in Co3O4/Al2O3) help minimise Co0 and CH4 formation. Therefore, this work reveals the bi-functional role required of supports used in CO-PrOx, i.e., to enhance catalytic performance and improve the phase stability of Co3O4.	Jun 2021
B18-Core EXAFS	Impact of nanoparticle-support interactions in co3o4/al2o3 catalysts for the preferential oxidation of carbon monoxide Thulani M. Nyathi , Nico Fischer , Andrew P. E. York , David J. Morgan , Graham J. Hutchings , Emma K. Gibson , Peter Wells , C. Richard A. Catlow , Michael Claeys Acs Catalysis DOI: 10.1021/acscatal.9b00685 Diamond Proposal Number(s): [16006] Open Access Show Abstract ▼ Abstract: Different supporting procedures were followed to alter the nanoparticle-support interactions (NPSI) in two Co3O4/Al2O3 catalysts, prepared using the reverse micelle technique. The catalysts were tested in the dry preferential oxidation of carbon monoxide (CO-PrOx) while monitoring their phase stability using four complementary in situ techniques, viz. magnet-based characterisation, PXRD, combined XAS/DRIFTS as well as quasi in situ XPS, respectively. The catalyst with weak NPSI achieved higher CO2 yields and selectivities at temperatures below 225 °C compared to the sample with strong NPSI. However, relatively high degrees of reduction of Co3O4 to metallic Co were reached between 250 and 350 °C for the same catalyst. The presence of metallic Co led to the undesired formation of CH4, reaching a yield of over 90% above 300 °C. The catalyst with strong NPSI formed very low amounts of metallic Co (less than 1%) and low CH4 (yield of up to 20%) even at 350 °C. When the temperature was decreased from 350 to 50 °C under the reaction gas, both catalysts were slightly re-oxidised and gradually re-gained their CO oxidation activity while the formation of CH4 diminished. The present study, for the first time, shows a strong relationship between catalyst performance (i.e., activity and selectivity) and phase stability, both of which are affected by the strength of the NPSI. When using a metal oxide as the active CO-PrOx catalyst, it is important for it to have significant reduction resistance to avoid the formation of undesired products, e.g., CH4. However, the metal oxide should also be reducible (especially on the surface) to allow for a complete conversion of CO to CO2 via the Mars-van Krevelen mechanism.	Jun 2019

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User