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54. Studies on ultra clean carbon surfaces—III. Kinetics of hydrogen chemisorption on graphon
ABSTRACTS
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51. Carbon-sulphur surface complexes B. R. Puri (C@mistry Department, Panjab University, Chadigarh 14, India). Carbon-sulphur surface complexes of great stability are obtained on heating activated carbons or carbon blacks with sulphur, hydrogen sulphide, carbon disulphide and sulphur dioxide, and to some extent, even on mere contact with aqueous hydrogen sulphide. The combined sulphur influences reactivity and catalytic properties and comes off as carbon disulphide and hydrogen sulphide. The mechanisms and the sites involved and the nature of the sulphur groups have been discussed. 5% Changes in graphite pore structure arising from irradiation induced attackin CO2 V. Y. Labaton and B. W. Ashton (U.K.A.E.A. Reactor Materials Laboratory, Culcheth, Nr. Warrington, Lancashire, U.K.). Pore structure changes have been determined for a number of commercial nuclear graphites radiolytically oxidised in carbon dioxide. Measurements have included open and closed porosity, pore size distribution, B.E.T. surface area and gas transport. The implications of pore structure changes on radiolytic oxidation rates are discussed. 53. Surface oxygen complex on a non-graphitic carbon J. J. Dollimore, C. M. Freedman and B. H. Harrison (Department ofPure and Applied Physics, University of Salford, Salford 5, Lancashire, U.K.). A mass spectrometer technique is used to study the formation of surface oxide on the clear surface of Saran Charcoal, at a temperature of 300°C. A material balance was obtained for oxygen chemisorbing as surface oxide. The thermal decomposition of this surface complex to carbon dioxide and monoxide was evaluated. This work is compared to the more extensive published data available on graphites. 54. Studies on ultra clean carbon surfaces -111. Kinetics of hydrogen chemisorption on graphon* R. C. Bansal, F. J. Vastola and P. L. Walker, Jr. (The Pennsylvania State University, Materials Science Department, University Park, Pennsylvania). Kinetics of hydrogen chemisorption on an ultra-clean surface of Graphon at temperatures between 25”-800°C have been studied. Elovich plots show the existence of discrete types of sites. The activation energy of adsorption on these different types of sites have been calculated and shall be compared with the theoretical values. The effect of preadsorbed hydrogen on the subsequent chemisorption of oxygen shall also be discussed. *Supported by the Atomic Energy on Contract No. AT(30-l)-1710. The influence of chemisorbed gases on the parahydrogen conversion over diamond* D. E. Brown, Y. Ishikawa, R. Sappokt and P. L. Walker, Jr. (The Pennsylvania State University, Materials Science Department, University Part, Pennsylvania). Samples of powdered diamond (surface area 20 m/g) have been treated with hydrogen at 9OO”C,oxygen at 400°C and chlorine at 400°C. The rate of the parahydrogen conversion on these samples outgassed at temperatures from 25” to 950°C has been measured and compared with the E.S.R. absorption data obtained from similar samples. The techniques are used to determine the nature of ‘free valencies’ at the diamond surface. 55.
*Supported by the Atomic Energy Commission on Contract No. AT(30-I)-1710. i-Now at the Anorganisch-Chemisches Institut der Universitat, Heidelberg, Germany
56. Functional groups on carbon black: infrared and supporting studies M. L. Studebaker (Phillips Petroleum Company, Akron, Ohio) and R. W. Rinehart, Sr. (Huffman Laboratories, Inc., Wheatridge, Colorado). Published work is discussed. Data derived from infrared studies is reported and correlated with published work. Supporting studies involving other techniques will be correlated with the result of the infrared studies. 57. Adsorption from solution on characterised porous carbons H. G. Campbell and H. Marsh (Northern Coke Research Laboratories, School of Chemistry, The University of Newcastle upon Tyne, Newcastle upon Tyne, NEZ 7RU, U.K.). Carbons prepared from polyvinylidene chloride and polyfurfuryl alcohol were activated progressively by slow combustion in carbon dioxide. The porosity developed was characterised from gas phase adsorption isotherms (Hz at 77°K and CO, at 273°K) using Dubinin and BNT theory. These carbons were adsorbents in such systems as (a) water-pnitrophenol, (b) water-glutaric acid, (c) water-malonic acid, (d) acetic acid-carbon tetrachloride. The aim was to examine the possibility that such systems can give a measure to surface areas of porous carbons as well as carbon blacks (cf. Kipling). The results suggest they cannot.
717
51. Carbon-sulphur surface complexes B. R. Puri (C@mistry Department, Panjab University, Chadigarh 14, India). Carbon-sulphur surface complexes of great stability are obtained on heating activated carbons or carbon blacks with sulphur, hydrogen sulphide, carbon disulphide and sulphur dioxide, and to some extent, even on mere contact with aqueous hydrogen sulphide. The combined sulphur influences reactivity and catalytic properties and comes off as carbon disulphide and hydrogen sulphide. The mechanisms and the sites involved and the nature of the sulphur groups have been discussed. 5% Changes in graphite pore structure arising from irradiation induced attackin CO2 V. Y. Labaton and B. W. Ashton (U.K.A.E.A. Reactor Materials Laboratory, Culcheth, Nr. Warrington, Lancashire, U.K.). Pore structure changes have been determined for a number of commercial nuclear graphites radiolytically oxidised in carbon dioxide. Measurements have included open and closed porosity, pore size distribution, B.E.T. surface area and gas transport. The implications of pore structure changes on radiolytic oxidation rates are discussed. 53. Surface oxygen complex on a non-graphitic carbon J. J. Dollimore, C. M. Freedman and B. H. Harrison (Department ofPure and Applied Physics, University of Salford, Salford 5, Lancashire, U.K.). A mass spectrometer technique is used to study the formation of surface oxide on the clear surface of Saran Charcoal, at a temperature of 300°C. A material balance was obtained for oxygen chemisorbing as surface oxide. The thermal decomposition of this surface complex to carbon dioxide and monoxide was evaluated. This work is compared to the more extensive published data available on graphites. 54. Studies on ultra clean carbon surfaces -111. Kinetics of hydrogen chemisorption on graphon* R. C. Bansal, F. J. Vastola and P. L. Walker, Jr. (The Pennsylvania State University, Materials Science Department, University Park, Pennsylvania). Kinetics of hydrogen chemisorption on an ultra-clean surface of Graphon at temperatures between 25”-800°C have been studied. Elovich plots show the existence of discrete types of sites. The activation energy of adsorption on these different types of sites have been calculated and shall be compared with the theoretical values. The effect of preadsorbed hydrogen on the subsequent chemisorption of oxygen shall also be discussed. *Supported by the Atomic Energy on Contract No. AT(30-l)-1710. The influence of chemisorbed gases on the parahydrogen conversion over diamond* D. E. Brown, Y. Ishikawa, R. Sappokt and P. L. Walker, Jr. (The Pennsylvania State University, Materials Science Department, University Part, Pennsylvania). Samples of powdered diamond (surface area 20 m/g) have been treated with hydrogen at 9OO”C,oxygen at 400°C and chlorine at 400°C. The rate of the parahydrogen conversion on these samples outgassed at temperatures from 25” to 950°C has been measured and compared with the E.S.R. absorption data obtained from similar samples. The techniques are used to determine the nature of ‘free valencies’ at the diamond surface. 55.
*Supported by the Atomic Energy Commission on Contract No. AT(30-I)-1710. i-Now at the Anorganisch-Chemisches Institut der Universitat, Heidelberg, Germany
56. Functional groups on carbon black: infrared and supporting studies M. L. Studebaker (Phillips Petroleum Company, Akron, Ohio) and R. W. Rinehart, Sr. (Huffman Laboratories, Inc., Wheatridge, Colorado). Published work is discussed. Data derived from infrared studies is reported and correlated with published work. Supporting studies involving other techniques will be correlated with the result of the infrared studies. 57. Adsorption from solution on characterised porous carbons H. G. Campbell and H. Marsh (Northern Coke Research Laboratories, School of Chemistry, The University of Newcastle upon Tyne, Newcastle upon Tyne, NEZ 7RU, U.K.). Carbons prepared from polyvinylidene chloride and polyfurfuryl alcohol were activated progressively by slow combustion in carbon dioxide. The porosity developed was characterised from gas phase adsorption isotherms (Hz at 77°K and CO, at 273°K) using Dubinin and BNT theory. These carbons were adsorbents in such systems as (a) water-pnitrophenol, (b) water-glutaric acid, (c) water-malonic acid, (d) acetic acid-carbon tetrachloride. The aim was to examine the possibility that such systems can give a measure to surface areas of porous carbons as well as carbon blacks (cf. Kipling). The results suggest they cannot.