[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-510984-105":59,"doc-detail-510984-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","unexpected-trends-in-the-enhanced-ce3-surface-concentration-in-ceriazirconia-catalyst-materials-paper","Unexpected trends in the enhanced Ce3+ surface concentration in ceria–zirconia catalyst materials - Paper","","The study investigates ceria–zirconia solid solutions in heterogeneous catalysis, focusing on how much Ce3+ is present at material surfaces versus in the bulk, under technologically relevant conditions. Using angle-resolved X-ray Absorption Near Edge Spectroscopy (XANES) on thin films grown on YSZ (001), the work quantifies Ce3+ in 2–3 nm surface and bulk regions. Substantial surface Ce3+ enrichment is observed in all cases, with the highest enhancement occurring in the absence of Zr, unlike bulk trends.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/unexpected-trends-in-the-enhanced-ce3-surface-concentration-in-ceriazirconia-catalyst-materials-paper/510984/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/unexpected-trends-in-the-enhanced-ce3-surface-concentration-in-ceriazirconia-catalyst-materials-paper/510984.png","ImageObject",300,407,{"name":92,"@type":93},"Well Done","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-11-10","2026-10-06",true,{"@type":102,"interactionType":103,"userInteractionCount":19},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What technique is used to quantify Ce3+ concentrations at surfaces and in the bulk?","Question",{"text":112,"@type":113},"Angle-resolved X-ray Absorption Near Edge Spectroscopy (XANES) is used to quantify Ce3+ concentration in both surface (2–3 nm) and bulk regions.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How do surface Ce3+ concentrations compare with bulk concentrations?",{"text":117,"@type":113},"Across all tested circumstances, the surfaces show substantial Ce3+ enrichment compared with the bulk.",{"name":119,"@type":110,"acceptedAnswer":120},"What is the key unexpected trend regarding zirconium content?",{"text":121,"@type":113},"The degree of Ce3+ enhancement at the surface is highest when Zr is absent, which contrasts with the bulk behavior where Ce3+ monotonically increases with increasing Zr content.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},510984,1792888725,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":19,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":44,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":144,"preview_page_count":4},5909892210082,"https://ap-avatar.wpscdn.com/avatar/56001069da27c9f41e8?x-image-process=image/resize,m_fixed,w_180,h_180&k=1789614185077863061","Pu on 6/30/2020blished on 30 April 2020. Downloaded by Northwestern University 3:15:10 AM .  \nJournal of  \nMaterials Chemistry A  \nPAPER  \nView Article Online View Journal | View Issue  \nCite this: J. Mater. Chem. A, 2020, 8, 9850  \nReceived 9th March 2020  \nAccepted 24th April 2020  \nDOI: 10.1039/d0ta02762f[rsc.li/materials-a](rsc.li/materials-a)  \nUnexpected trends in the enhanced Ce3+ surface concentration in ceria–zirconia catalyst materials†  \nWeizi Yuan,  a Qing Ma, b Yangang Liang,c Chengjun Sun,d  \nK. V. L. V. Narayanachari,a Michael J. Bedzyk,  a Ichiro Takeuchicand Sossina M. Haile  *a  \nDespite the immense importance of ceria–zirconia solid solutions in heterogeneous catalysis, and the growing consensus that catalytic activity correlates with the concentration of reduced Ce3+ species and accompanying oxygen vacancies, the extent of reduction at the surfaces of these materials, where catalysis occurs, is unknown. Using angle-resolved X-ray Absorption Near Edge Spectroscopy (XANES), we quantify under technologically relevant conditions the Ce3+ concentration in the surface (2–3 nm) and bulk regions of ceria–zirconia films grown on single crystal yttria-stabilized zirconia, YSZ (001) . In all circumstances, we observe substantial Ce3+ enrichment at the surface relative to the bulk. Surprisingly, the degree of enhancement is highest in the absence of Zr. This behavior stands in direct contrast to that of the bulk in which the Ce3+ concentration monotonically increases with increasing Zr content. These results suggest that while Zr enhances the oxygen storage capacity in ceria, undoped ceria may have higher surface catalytic activity. They further urge caution in the use of bulk properties as surrogate descriptors for surface characteristics and hence catalytic activity.  \nIntroduction  \nCeria (CeO2􀀁d) and ceria–zirconia (Ce1􀀁xZrxO2􀀁d) solid solutions are important catalytic materials, either serving directly as catalysts themselves, or serving as supports for metal nanoparticle catalysts.1–4 The ease with which Ce undergoes changes in oxidation state is believed to account for the buffering capacity of ceria, which in turn is associated with its high catalytic activity.5 Introduction of zirconium increases thereducibility of the material,2,6–9 as has been quanti􀀁ed in recent measurements which reveal the relationship between bulk oxidation state, bulk vacancy concentration and environmental conditions.10–12 This behavior is quite distinct from that of rareearth doping of ceria, which largely leaves the bulk thermodynamic properties unchanged from those of undoped ceria.13 Arguably, however, the redox properties of the surfaces are likely to be more important to the catalytic characteristics than those of the bulk. Here, quantitative data are scarce, particularly with respect to operando (experimental) observations.  \naDepartment of Materials Science and Engineering, Northwestern University, Illinois 60208, USA. E-mail: [sossina.haile@northwestern.edu](sossina.haile@northwestern.edu)  \nbDND-CAT, Northwestern Synchrotron Research Center at the Advanced Photon Source, Argonne, Illinois 60439, USA  \ncDepartment of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA  \ndAdvanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA † Electronic supplementary information (ESI) available. See DOI: 10.1039/d0ta02762f  \nComputational studies of the ceria–zirconia system suggest enhanced surface vacancy concentrations relative to the bulk.4,5,14–20 In particular, Balducci et al. have predicted that oxygen vacancy segregation to the surface increases with Zr content and is more pronounced in the sequence (310) > (110) >(111), in accord with the sequence of stability of these surfaces.15 In a series of studies of CeO2 and Ce0.75Zr0.25O2, Yang et al.17–19 found (110) and (111) surface vacancy formation energies in all cases to be lower than those of the bulk, but in contrast t","cbCaibVsszu1fI3B","https://ap.wps.com/l/cbCaibVsszu1fI3B","pdf",863541,"English","# Introduction\n## Redox behavior of ceria and ceria–zirconia\n## Importance of surface versus bulk properties\n## Challenges in detecting oxygen vacancies","[{\"question\":\"What technique is used to quantify Ce3+ concentrations at surfaces and in the bulk?\",\"answer\":\"Angle-resolved X-ray Absorption Near Edge Spectroscopy (XANES) is used to quantify Ce3+ concentration in both surface (2–3 nm) and bulk regions.\"},{\"question\":\"How do surface Ce3+ concentrations compare with bulk concentrations?\",\"answer\":\"Across all tested circumstances, the surfaces show substantial Ce3+ enrichment compared with the bulk.\"},{\"question\":\"What is the key unexpected trend regarding zirconium content?\",\"answer\":\"The degree of Ce3+ enhancement at the surface is highest when Zr is absent, which contrasts with the bulk behavior where Ce3+ monotonically increases with increasing Zr content.\"}]","Unexpected trends in the enhanced Ce3+ surface concentration in ceria–zirconia catalyst materials - Paper | PDF",1791246778,23]