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Papers by Eliceo Hernández
This work describes the results from the tests performed to a new sensor cable used for detecting... more This work describes the results from the tests performed to a new sensor cable used for detecting and locating third party damages to any kind of buried pipelines, either by intention or accident. Additionally, the sensor cable has a potential application to oil pipelines transport exposed to illegal extractions as well as to high consequence zones. For instance, if someone tries to steal fuel from a pipeline or a pipeline is hit and a leak is caused, the hydrocarbon will get in contact with the sensor cable wall and the leak will be detected and located by measuring the cable resistance. This work makes reference to the advantages of the new sensor cable compared to cables with similar characteristics; such advantages, which have been proved through experiments, include: the response time is shorter; since it is made out of several wires, it avoids false alarms; since it is made out of steel mesh, it protects pipelines from electromagnetic interference, which would negatively affec...
Quantum Matter, 2014
ABSTRACT A density functional theory study was carried out on the binding of atomic hydrogen on s... more ABSTRACT A density functional theory study was carried out on the binding of atomic hydrogen on small neutral and charged Pt m Au n (m+n ≤ 5) cluster. It is found that the composition and charge state of clusters have strong influence on the most stable binding site. The adiabatic ionization potentials, electron affinities, and hydrogen binding energies of cluster hydrides display complicate tendency, this may be caused by the small size of Pt m Au n (m+n ≤ 5) cluster and hence the H binding change the stable structure greatly and energy. The dissociation channels for neutral and charged hydride clusters are very different and most clusters tend to eject H atom and Au, Au2, Pt, Pt2, AuH and PtH may also be ejected. All cluster vibrations are calculated in detail. Pt—H and Au—H display three kinds of vibrations: stretching, rocking (planar) and wagging (non-planar) with its characteristic frequency.
Journal of Nanoscience and Nanotechnology, 2014
This paper reviews the recent research and development of bimetallic clusters. Small bimetallic n... more This paper reviews the recent research and development of bimetallic clusters. Small bimetallic nanoscale clusters often have physical and chemical properties that are distinct from those of their pure bulk counterparts and suggestive of novel applications. Their chemical and physical properties can be controlled by varying the cluster size and composition as well as the temperature. Therefore the starting point for an understanding of bimetallic clusters is the study of their structures. The typical most stable structure: cuboctahedron, decahedron, icosahedron and Marks decahedron etc. According to the elemental distribution in bimetallic clusters, they can be divided into solid solution type, core/shell, eutectic-like etc. Complete phase separation is found in some bimetallic systems in specific conditions. The most stable structure of a bimetallic cluster is affected by the interatomic interaction potential, especially the alloying interaction, radius of the metal atom or the nearest neighbor distance in its stable bulk crystalline, temperature, concentration of each component, and the size of the clusters. In certain dynamic synthesis conditions such as substrate, non-most stable structure can form and exist, and can transform into a stable structure under some conditions such as heating.
Journal of The Electrochemical Society, 2014
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and the electrochemical activities toward methanol oxidation were compared. Pt, MoO 2 and MoO 3 phases were well identified with the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.
Journal of Mechanical Science and Technology
ECS Transactions, 2000
ABSTRACT Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic s... more ABSTRACT Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
ECS Transactions
Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was ... more Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
ECS Transactions
Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was ... more Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and the electrochemical activities toward methanol oxidation were compared. Pt, MoO 2 and MoO 3 phases were well identified with the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized
following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The
obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission
electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and
the electrochemical activities toward methanol oxidation were compared. Pt, MoO2 and MoO3 phases were well identified with
the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably
different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and
aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum
oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the
catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.
This work describes the results from the tests performed to a new sensor cable used for detecting... more This work describes the results from the tests performed to a new sensor cable used for detecting and locating third party damages to any kind of buried pipelines, either by intention or accident. Additionally, the sensor cable has a potential application to oil pipelines transport exposed to illegal extractions as well as to high consequence zones. For instance, if someone tries to steal fuel from a pipeline or a pipeline is hit and a leak is caused, the hydrocarbon will get in contact with the sensor cable wall and the leak will be detected and located by measuring the cable resistance. This work makes reference to the advantages of the new sensor cable compared to cables with similar characteristics; such advantages, which have been proved through experiments, include: the response time is shorter; since it is made out of several wires, it avoids false alarms; since it is made out of steel mesh, it protects pipelines from electromagnetic interference, which would negatively affec...
Quantum Matter, 2014
ABSTRACT A density functional theory study was carried out on the binding of atomic hydrogen on s... more ABSTRACT A density functional theory study was carried out on the binding of atomic hydrogen on small neutral and charged Pt m Au n (m+n ≤ 5) cluster. It is found that the composition and charge state of clusters have strong influence on the most stable binding site. The adiabatic ionization potentials, electron affinities, and hydrogen binding energies of cluster hydrides display complicate tendency, this may be caused by the small size of Pt m Au n (m+n ≤ 5) cluster and hence the H binding change the stable structure greatly and energy. The dissociation channels for neutral and charged hydride clusters are very different and most clusters tend to eject H atom and Au, Au2, Pt, Pt2, AuH and PtH may also be ejected. All cluster vibrations are calculated in detail. Pt—H and Au—H display three kinds of vibrations: stretching, rocking (planar) and wagging (non-planar) with its characteristic frequency.
Journal of Nanoscience and Nanotechnology, 2014
This paper reviews the recent research and development of bimetallic clusters. Small bimetallic n... more This paper reviews the recent research and development of bimetallic clusters. Small bimetallic nanoscale clusters often have physical and chemical properties that are distinct from those of their pure bulk counterparts and suggestive of novel applications. Their chemical and physical properties can be controlled by varying the cluster size and composition as well as the temperature. Therefore the starting point for an understanding of bimetallic clusters is the study of their structures. The typical most stable structure: cuboctahedron, decahedron, icosahedron and Marks decahedron etc. According to the elemental distribution in bimetallic clusters, they can be divided into solid solution type, core/shell, eutectic-like etc. Complete phase separation is found in some bimetallic systems in specific conditions. The most stable structure of a bimetallic cluster is affected by the interatomic interaction potential, especially the alloying interaction, radius of the metal atom or the nearest neighbor distance in its stable bulk crystalline, temperature, concentration of each component, and the size of the clusters. In certain dynamic synthesis conditions such as substrate, non-most stable structure can form and exist, and can transform into a stable structure under some conditions such as heating.
Journal of The Electrochemical Society, 2014
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and the electrochemical activities toward methanol oxidation were compared. Pt, MoO 2 and MoO 3 phases were well identified with the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.
Journal of Mechanical Science and Technology
ECS Transactions, 2000
ABSTRACT Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic s... more ABSTRACT Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
ECS Transactions
Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was ... more Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
ECS Transactions
Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was ... more Different carbon-supported Pt-Mo and Pt-Ru materials were synthesized and a systematic study was carried out in order to evaluate their catalytic activity towards methanol oxidation. Direct current methods were applied in sulfuric acid and methanol - containing electrolytes, in order to evaluate the electrochemical response of the studied electrodes. Pt-Mo catalysts reveal similar performances and, in some cases, higher than Pt-Ru materials. For both catalysts series, it was found that low loadings of the promoting metal (Ru or Mo) improve the methanol oxidation activity. Characterizations by means of transmission electron microscopy and X-Ray Diffraction allowed to measure mean particle sizes below 10 nm for all phases. The Pt-Ru catalysts consist of metallic Pt and metallic ruthenium, while in the The Pt-Mo materials platinum is present in its metallic state and MoO3 is the predominant molybdenum species.
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and the electrochemical activities toward methanol oxidation were compared. Pt, MoO 2 and MoO 3 phases were well identified with the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.
Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and ... more Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized
following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The
obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission
electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and
the electrochemical activities toward methanol oxidation were compared. Pt, MoO2 and MoO3 phases were well identified with
the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably
different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and
aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum
oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the
catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity.