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

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

Instruments / Technical Area	Publication Details	Published
B18-Core EXAFS	The role of growth directors in controlling the morphology of hematite nanorods Christopher J. Allender , Jenna L. Bowen , Veronica Celorrio , Josh A. Davies-jones , Philip R. Davies , Shaoliang Guan , Padraic O’reilly , Meenakshisundaram Sankar Nanoscale Research Letters 15 DOI: 10.1186/s11671-020-03387-w Diamond Proposal Number(s): [15151] Open Access Show Abstract ▼ Abstract: The control of the growth of hematite nanoparticles from iron chloride solutions under hydrothermal conditions in the presence of two different structure promoters has been studied using a range of both structural and spectroscopic techniques including the first report of photo induced force microscopy (PiFM) to map the topographic distribution of the structure-directing agents on the developing nanoparticles. We show that the shape of the nanoparticles can be controlled using the concentration of phosphate ions up to a limit determined to be ~6 × 10−3 mol. Akaganéite (β-FeOOH) is a major component of the nanoparticles formed in the absence of structure directors but only present in the very early stages (< 8 h) of particle growth when phosphate is present. The PiFM data suggest a correlation between the areas in which phosphate ions are adsorbed and areas where akaganéite persists on the surface. In contrast, goethite (α-FeOOH) is a directly observed precursor of the hematite nanorods when 1,2-diamino propane is present. The PiFM data shows goethite in the center of the developing particles consistent with a mechanism in which the iron hydroxide re-dissolves and precipitates at the nanorod ends as hematite.	Aug 2020
B18-Core EXAFS E01-JEM ARM 200CF E02-JEM ARM 300CF I11-High Resolution Powder Diffraction I20-Scanning-X-ray spectroscopy (XAS/XES)	Adsorption and activation of molecular oxygen over atomic copper(I/II) site on ceria Liqun Kang , Bolun Wang , Qiming Bing , Michal Zalibera , Robert Büchel , Ruoyu Xu , Qiming Wang , Yiyun Liu , Diego Gianolio , Chiu C. Tang , Emma K. Gibson , Mohsen Danaie , Christopher Allen , Ke Wu , Sushila Marlow , Ling-dong Sun , Qian He , Shaoliang Guan , Anton Savitsky , Juan J. Velasco-vélez , June Callison , Christopher W. M. Kay , Sotiris E. Pratsinis , Wolfgang Lubitz , Jing-yao Liu , Feng Ryan Wang Nature Communications 11 DOI: 10.1038/s41467-020-17852-8 Diamond Proposal Number(s): [15151, 15763, 16966, 17377, 19072, 19246, 20939, 17559, 24285, 19318, 19850] Open Access Show Abstract ▼ Abstract: Supported atomic metal sites have discrete molecular orbitals. Precise control over the energies of these sites is key to achieving novel reaction pathways with superior selectivity. Here, we achieve selective oxygen (O2) activation by utilising a framework of cerium (Ce) cations to reduce the energy of 3d orbitals of isolated copper (Cu) sites. Operando X-ray absorption spectroscopy, electron paramagnetic resonance and density-functional theory simulations are used to demonstrate that a [Cu(I)O2]3− site selectively adsorbs molecular O2, forming a rarely reported electrophilic η2-O2 species at 298 K. Assisted by neighbouring Ce(III) cations, η2-O2 is finally reduced to two O2−, that create two Cu–O–Ce oxo-bridges at 453 K. The isolated Cu(I)/(II) sites are ten times more active in CO oxidation than CuO clusters, showing a turnover frequency of 0.028 ± 0.003 s−1 at 373 K and 0.01 bar PCO. The unique electronic structure of [Cu(I)O2]3− site suggests its potential in selective oxidation.	Aug 2020
B18-Core EXAFS	Evolution of palladium sulfide phases during thermal treatments and consequences for acetylene hydrogenation Yanan Liu , Alan J. Mccue , Junting Feng , Shaoliang Guan , Dianqing Li , James A. Anderson Journal Of Catalysis 364, 204 - 215 DOI: 10.1016/j.jcat.2018.05.018 Diamond Proposal Number(s): [15151] Show Abstract ▼ Abstract: Unsupported, bulk phase palladium sulfide has been studied for the selective hydrogenation of acetylene. The sample underwent significant change during thermal pretreatments, the extent of which depends on temperature. Exposure to hydrogen at temperatures of 150 °C or above results in the loss of sulfur from the sample, primarily as hydrogen sulfide. As sulfur is lost, the sample is progressively transformed from a sulfur rich phase (PdS) to a sulfur lean phase (Pd4S) via an intermediate phase (Pd16S7). Reduction at 250 °C produces a material, which contains Pd4S as the surface phase, whereas reduction at 350 °C results in a largely pure Pd4S phase. Thermal treatments which produce a Pd4S surface display excellent catalytic properties. At complete acetylene conversion at 250 °C, ethylene selectivities of 82.8% and 90.0% were obtained under non-competitive and competitive conditions, respectively. Beneficial catalytic properties arise from the uniformity of Pd sites due to the crystal structure of Pd4S along with electronic influences on the adsorption/desorption processes arising from sulfur neighbours. No indications of deactivation or significant deposition of carbon were observed over Pd4S sample after 50 h on stream.	Aug 2018
B18-Core EXAFS	Structural behaviour of copper chloride catalysts during the chlorination of CO to phosgene Shaoliang Guan , Philip R. Davies , Emma K. Gibson , David Lennon , Giovanni E. Rossi , John M. Winfield , June Callison , Peter P. Wells , David J. Willock Faraday Discussions DOI: 10.1039/C8FD00005K Diamond Proposal Number(s): [10306] Open Access Show Abstract ▼ Abstract: The interaction of CO with an attapulgite-supported Cu(II)Cl2 catalyst has been examined in a micro-reactor arrangement. CO exposure to the dried, as-received catalyst at elevated temperatures leads to the formation of CO2 as the only identifiable product. However, phosgene production can be induced by a catalyst pre-treatment where the supported Cu(II)Cl2 sample is exposed to a diluted stream of chlorine. Subsequent CO exposure at  370C then leads to phosgene production. In order to investigate the origins of this atypical set of reaction characteristics, a series of x-ray absorption experiments were performed that were supplemented by DFT calculations. XANES measurements establish that at the elevated temperatures connected with phosgene formation, the catalyst is comprised of Cu+ and a small amount of Cu2+. Moreover, the data show that unique to the chlorine pre-treated sample, CO exposure at elevated temperature results in a short-lived oxidation of the copper. On the basis of calculated CO adsorption energies, DFT calculations indicate that a mixed Cu+/Cu2+ catalyst is required to support CO chemisorption.	Feb 2018

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