Interfacial sites in platinum-hydroxide-cobalt hybrid nanostructures for promoting CO oxidation activity.

Metal-oxide/hydroxide hybrid nanostructures provide an excellent platform to study the interfacial effects on tailoring the catalysis of metal catalysts. Herein, a hybrid nanostructure of Pt@Co(OH)2 supported on SiO2 was synthesized by incipient wetness impregnation of Co(OH)2 with the aid of H2O2 and successive urea-assisted deposition-precipitation of platinum nanoparticles. The Fenton-like reaction between Co2+ and H2O2 during the impregnation process facilitates the formation of active interfacial sites. This hybrid nanostructure exhibits much higher catalytic activity towards CO oxidation than Pt/SiO2 nanoparticles with a similar Pt loading and particle size. In situ diffuse reflectance infrared Fourier transform spectroscopy was used to track the CO adsorption processes and to identify the reaction intermediates during CO oxidation. It shows that the OH species at the Pt-OH-Co interfacial sites could readily react with CO adsorbed on neighboring Pt to yield CO2 by forming *COOH intermediates and oxygen vacancies. Under the CO + O2 oxidation conditions, O2 molecules are activated by the oxygen vacancy and react with the CO molecules adsorbed on Pt to generate CO2, via forming the highly active *OOH intermediates as observed by DRIFTS.

In situ observations of the structural dynamics of platinum-cobalt-hydroxide nanocatalysts under CO oxidation.

The structures, compositions and chemical states of metal catalysts are prone to dynamic changes in response to reaction conditions. In this work, a combination of in situ X-ray absorption fine structure spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy has been used to monitor the temperature-dependent structural dynamics in bimetallic Pt-Co(OH)2 nanocatalysts during CO oxidation. Alloying with electron-donating Co promotes the catalytic activity of metallic Pt for CO oxidation at low temperature. At elevated temperatures under an oxidation atmosphere, O2 drives the segregation of the Pt-Co alloy into cobalt oxide and platinum metal, with the extent of alloying sharply decreasing from ∼30% at 300 K to 0 at 473 K. Reduction at high temperature could recover the formation of the Pt-Co alloy with the same alloying extent. The observed structural dynamics could be well correlated with the kinetic behavior of the catalysts. This work highlights the importance of tracking the dynamic structural changes of working catalysts for a correct understanding of their catalytic behavior.

Survey of spinal cord injury-induced neurogenic bladder studies using the Web of Science.

OBJECTIVE: To identify global trends in research on spinal cord injury-induced neurogenic bladder, through a bibliometric analysis using the Web of Science. DATA RETRIEVAL: We performed a bibliometric analysis of studies on spinal cord injury-induced neurogenic bladder using the Web of Science. Data retrieval was performed using key words "spinal cord injury", "spinal injury", "neurogenic bladder", "neuropathic bladder", "neurogenic lower urinary tract dysfunction", "neurogenic voiding dysfunction", "neurogenic urination disorder" and "neurogenic vesicourethral dysfunction". INCLUSION CRITERIA: (a) published peer-reviewed articles on spinal cord injury-induced neurogenic bladder indexed in the Web of Science; (b) type of articles: original research articles and reviews; (c) year of publication: no limitation. EXCLUSION CRITERIA: (a) articles that required manual searching or telephone access; (b) Corrected papers and book chapters. MAIN OUTCOME MEASURES: (1) Annual publication output; (2) distribution according to journals; (3) distribution according to subject areas; (4) distribution according to country; (5) distribution according to institution; and (6) top cited publications. RESULTS: There were 646 research articles addressing spinal cord injury-induced neurogenic bladder in the Web of Science. Research on spinal cord injury-induced neurogenic bladder was found in the Science Citation Index-Expanded as of 1946. The United States, Ireland and Switzerland were the three major countries contributing to studies in spinal cord injury-induced neurogenic bladder in the 1970s. However, in the 1990s, the United States, the United Kingdom, the Netherlands, Germany and Japan published more papers on spinal cord injury-induced neurogenic bladder than Switzerland, and Ireland fell off the top ten countries list. In this century, the United States ranks first in spinal cord injury-induced neurogenic bladder studies, followed by France, the United Kingdom, Germany, Switzerland and Japan. Subject categories including urology, nephrology and clinical neurology, as well as rehabilitation, are represented in spinal cord injury-induced neurogenic bladder studies. CONCLUSION: From our analysis of the literature and research trends, we conclude that spinal cord injury-induced neurogenic bladder is a hot topic that will continue to generate considerable research interest in the future.