{"id":160,"date":"2014-08-01T15:45:55","date_gmt":"2014-08-01T15:45:55","guid":{"rendered":"http:\/\/sites.cardiff.ac.uk\/xpsaccess\/?page_id=160"},"modified":"2014-08-20T07:55:04","modified_gmt":"2014-08-20T07:55:04","slug":"gold","status":"publish","type":"page","link":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/reference\/gold\/","title":{"rendered":"Gold"},"content":{"rendered":"<p>There is a lot of current interest in the chemistry and especially the catalysis of gold, therefore there is a great interest in the reliable assignment of metallic and ionic gold species in XPS. \u00a0Typical Au(4f<sub>7\/2<\/sub>) binding energies are given below:<\/p>\n<p><span style=\"font-size: 14px;line-height: 1.5em\">Metallic Au: 84.0 eV<\/span><\/p>\n<p>Au(I):\u00a0<em>ca.<\/em> 85.0 eV<\/p>\n<p>Au(III):\u00a0<em>ca.<\/em> 86.0 eV<\/p>\n<p>Spin-orbit splitting of Au(4f) peaks: 3.7 eV<\/p>\n<p><strong>Important notes:<\/strong><\/p>\n<p>For supported catalysts, depending on the support material, size of the Au nano-particles and treatment conditions, the binding energy of the Au(4f) peaks will shift. \u00a0The influence of final and initial state effects should be considered in all cases. \u00a0See for example\u00a0Phys. Chem. Chem. Phys., 2003,\u00a0<strong>5<\/strong>, 172-177 and\u00a0<cite>ACS Nano<\/cite>,\u00a02012,\u00a06\u00a0(8), pp 6600\u20136613.<\/p>\n<p><span style=\"font-size: 14px;line-height: 1.5em\">Cationic gold, especially Au(III) species, undergo photo-reduction by the photo-emission process and therefore, the Au(4f) region should be acquired on its own, then again with the remaining regions of interest to assess the degree of reduction. \u00a0An example is given below for the analysis of the Au(III) salt &#8211; HAuCl4.<\/span><\/p>\n<figure class=\"image\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft\" alt=\"Reduction of HAuCl4.xH2O during XPS analysis.  Both Au(III) and Au(0) species are noted\" src=\"http:\/\/sites.cardiff.ac.uk\/xpsaccess\/files\/2014\/08\/Au3Au1.jpg\" width=\"576\" height=\"432\" \/><figcaption class=\"caption\">Reduction of HAuCl4.xH2O during XPS analysis. Both Au(III) and Au(0) species are noted. \u00a0<\/figcaption><figcaption class=\"caption\">Lower trace = initial scans; Upper trace = after 10 min irradiation<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>There is a lot of current interest in the chemistry and especially the catalysis of gold, therefore there is a great interest in the reliable assignment of metallic and ionic gold species in XPS. \u00a0Typical Au(4f7\/2) binding energies are given below: Metallic Au: 84.0 eV Au(I):\u00a0ca. 85.0 eV Au(III):\u00a0ca. 86.0 eV Spin-orbit splitting of Au(4f)<\/p>\n","protected":false},"author":829,"featured_media":0,"parent":147,"menu_order":0,"comment_status":"closed","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-160","page","type-page","status-publish","hentry"],"meta_box":[],"_links":{"self":[{"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/pages\/160","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/users\/829"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/comments?post=160"}],"version-history":[{"count":18,"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/pages\/160\/revisions"}],"predecessor-version":[{"id":197,"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/pages\/160\/revisions\/197"}],"up":[{"embeddable":true,"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/pages\/147"}],"wp:attachment":[{"href":"https:\/\/sites.cardiff.ac.uk\/xpsaccess\/wp-json\/wp\/v2\/media?parent=160"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}