THE CATALYTIC ROLE OF CORONENE FOR MOLECULAR HYDROGEN FORMATION

2011 ◽  
Vol 745 (1) ◽  
pp. L2 ◽  
Author(s):  
Vito Mennella ◽  
Liv Hornekær ◽  
John Thrower ◽  
Mario Accolla
Author(s):  
Tushar Suhasaria ◽  
Vito Mennella

Refractory dust grains have an important role to play in the chemistry of star and planet-forming regions. Their surfaces interact with interstellar gas and act as a catalyst for the formation of simple and complex molecules in space. Several mechanisms have been invoked to explain how molecular hydrogen is formed in reactions on dust grain surfaces in different regions of space. In this article, we give an overview of our understanding of the laboratory experiments, conducted over the last 20 years, that deal with H2 formation on interstellar grain analogs in space simulated conditions.


2005 ◽  
Vol 884 ◽  
Author(s):  
Santanu Chaudhuri ◽  
James T Muckerman

AbstractPresence of ∼2-4 % Ti is critical for reversible hydrogenation/rehydrogenation in NaAlH4. We have investigated the probable catalytic role of Ti in this complex multi-step process. The present part of our study concentrates on the rehydrogenation reaction, i.e., the reverse reaction that forms NaAlH4 from its constituent binary hydrides. First principles calculations using density functional theory (DFT) show that a particular arrangement of Ti atoms on the surface of Al metal promotes the chemisorption of molecular hydrogen. We also present comparisons with existing experimental data (EXAFS and TEM) to support the existence of such an arrangement on the surface.


2011 ◽  
Vol 197-198 ◽  
pp. 1096-1099
Author(s):  
Wen Xue Zhang ◽  
Xin Hu ◽  
Xiao Bin Lin ◽  
Cheng He

The most promising hydrogen storage materials are perhaps complex metal hydrides. Thus, a plausible first step in the rehydrogenation mechanism is proposed by simulating the reversible hydrogen storage in Zr-doped NaAlH4. It provides insight into the catalytic role of Zr atoms on an Al surface in the chemisorptions of molecular hydrogen. It is found that the diffusion of hydride species on Al-metallic phase and formation of Al hydride species is probably the key to syntheses the next products in the rehydrogenation reaction.


Friction ◽  
2021 ◽  
Author(s):  
Pengcheng Li ◽  
Chongyang Tang ◽  
Xiangheng Xiao ◽  
Yanmin Jia ◽  
Wanping Chen

AbstractThe friction between nanomaterials and Teflon magnetic stirring rods has recently drawn much attention for its role in dye degradation by magnetic stirring in dark. Presently the friction between TiO2 nanoparticles and magnetic stirring rods in water has been deliberately enhanced and explored. As much as 1.00 g TiO2 nanoparticles were dispersed in 50 mL water in 100 mL quartz glass reactor, which got gas-closed with about 50 mL air and a Teflon magnetic stirring rod in it. The suspension in the reactor was magnetically stirred in dark. Flammable gases of 22.00 ppm CO, 2.45 ppm CH4, and 0.75 ppm H2 were surprisingly observed after 50 h of magnetic stirring. For reference, only 1.78 ppm CO, 2.17 ppm CH4, and 0.33 ppm H2 were obtained after the same time of magnetic stirring without TiO2 nanoparticles. Four magnetic stirring rods were simultaneously employed to further enhance the stirring, and as much as 30.04 ppm CO, 2.61 ppm CH4, and 8.98 ppm H2 were produced after 50 h of magnetic stirring. A mechanism for the catalytic role of TiO2 nanoparticles in producing the flammable gases is established, in which mechanical energy is absorbed through friction by TiO2 nanoparticles and converted into chemical energy for the reduction of CO2 and H2O. This finding clearly demonstrates a great potential for nanostructured semiconductors to utilize mechanical energy through friction for the production of flammable gases.


1989 ◽  
Vol 264 (32) ◽  
pp. 19132-19137
Author(s):  
I K Dev ◽  
B B Yates ◽  
J Atashi ◽  
W S Dallas

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