Heats of Transfer in the Diffusion Layer before the Surface and the Surface Temperature for a Catalytic Hydrogen Oxidation (H2+ (1/2)O2→ H2O) Reaction

2006 ◽  
Vol 110 (11) ◽  
pp. 4080-4088 ◽  
Author(s):  
Lianjie Zhu ◽  
Ger J. M. Koper ◽  
Dick Bedeaux
Keyword(s):  
Surface Temperature ◽  
Diffusion Layer ◽  
Hydrogen Oxidation ◽  
Catalytic Hydrogen ◽  
Heats Of Transfer

scholarly journals Modeling Study on Heat Transfer in Marangoni Dropwise Condensation for Ethanol-Water Mixture Vapors

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6726
Author(s):  
Jinshi Wang ◽  
Ziqiang Ma ◽  
Yong Li ◽  
Weiqi Liu ◽  
Gen Li
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Temperature Difference ◽  
Diffusion Layer ◽  
Water Mixture ◽  
Dropwise Condensation ◽  
Heat Transfer Characteristics ◽  
Vapor Diffusion ◽  
Transfer Characteristics ◽  
Condensate Layer

In this paper, a model was developed to predict the heat transfer characteristics of Marangoni dropwise condensation. In accordance with the feature of Marangoni condensation, condensation was treated as dropwise condensation of mixture vapors. The condensation space was divided into two parts: the vapor diffusion layer and the condensate layer. For the condensate layer, the classical heat transfer calculation method of dropwise condensation was imitated to obtain the heat transfer characteristics. For the vapor diffusion layer, the heat transfer characteristics were achieved by solving the conservation equations. These heat transfer characteristics were coupled through the conjunct boundary, which was the vapor-liquid interface. The model was applied to the condensation of water-ethanol mixture vapors. A comparison with the existing experimental data showed that the developed model could basically reflect the influences of vapor-to-surface temperature difference, vapor concentration, vapor pressure, and vapor velocity on heat transfer characteristic of Marangoni condensation. Results showed that some differences existed between the calculation results and experimental results, but the prediction deviation of the model could be acceptable in the range of vapor-to-surface temperature difference where the condensation heat transfer coefficients reached peak values.

ChemInform Abstract: Dihydrogen Complexes of Metalloporphyrins: Characterization and Catalytic Hydrogen Oxidation Activity.

ChemInform ◽  
2010 ◽  
Vol 23 (44) ◽  
pp. no-no
Author(s):  
J. P. COLLMAN ◽  
P. S. WAGENKNECHT ◽  
J. E. HUTCHISON ◽  
N. S. LEWIS ◽  
M. A. LOPEZ ◽  
...  
Keyword(s):  
Hydrogen Oxidation ◽  
Oxidation Activity ◽  
Dihydrogen Complexes ◽  
Catalytic Hydrogen

scholarly journals Statistical theory of catalytic hydrogen oxidation processes. Basic equations

2021 ◽  
Vol 8 (2) ◽  
pp. 267-281
Author(s):  
P. P. Kostrobij ◽  
◽  
B. M. Markovych ◽  
I. A. Ryzha ◽  
M. V. Tokarchuk ◽  
...  
Keyword(s):  
Statistical Theory ◽  
Metal Surface ◽  
Diffusion Processes ◽  
Hydrogen Oxidation ◽  
Reaction Diffusion ◽  
Oxidation Processes ◽  
Transfer Equations ◽  
Catalytic Hydrogen ◽  
Basic Equations ◽  
Abbreviated Description

A statistical description for the processes of catalytic hydrogen oxidation is proposed taking into account the reaction--diffusion processes for magnetoactive ions and atoms adsorbed on the metal surface. The basic non-Markov transfer equations are obtained for the abbreviated description parameters of reaction-diffusion processes for magnetoactive ions and atoms adsorbed on the metal surface in the method of nonequilibrium statistical Zubarev operator. Weakly nonequilibrium reaction-diffusion processes are also considered.

scholarly journals Catalytic Hydrogen Combustion for Domestic and Safety Applications: A Critical Review of Catalyst Materials and Technologies

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4897
Author(s):  
Alina E. Kozhukhova ◽  
Stephanus P. du Preez ◽  
Dmitri G. Bessarabov
Keyword(s):  
Surface Temperature ◽  
Catalyst Support ◽  
Exothermic Reaction ◽  
Flow Speed ◽  
Hydrogen Combustion ◽  
Nox Formation ◽  
Significant Research ◽  
Catalytic Hydrogen ◽  
Commercial Applications ◽  
Reaction With Water

Spatial heating and cooking account for a significant fraction of global domestic energy consumption. It is therefore likely that hydrogen combustion will form part of a hydrogen-based energy economy. Catalytic hydrogen combustion (CHC) is considered a promising technology for this purpose. CHC is an exothermic reaction, with water as the only by-product. Compared to direct flame-based hydrogen combustion, CHC is relatively safe as it foregoes COx, CH4, and under certain conditions NOx formation. More so, the risk of blow-off (flame extinguished due to the high fuel flow speed required for H2 combustion) is adverted. CHC is, however, perplexed by the occurrence of hotspots, which are defined as areas where the localized surface temperature is higher than the average surface temperature over the catalyst surface. Hotspots may result in hydrogen’s autoignition and accelerated catalyst degradation. In this review, catalyst materials along with the hydrogen technologies investigated for CHC applications were discussed. We showed that although significant research has been dedicated to CHC, relatively limited commercial applications have been identified up to date. We further showed the effect of catalyst support selection on the performance and durability of CHC catalysts, as well as a holistic summary of existing catalysts used for various CHC applications and catalytic burners. Lastly, the relevance of CHC applications for safety purposes was demonstrated.

Catalytic hydrogen oxidation using zeolite RHO modified by silver nanoparticles

2012 ◽  
Vol 38 (5) ◽  
pp. 455-459 ◽  
Author(s):  
O. Yu. Golubeva ◽  
N. Yu. Ternovaya ◽  
N. V. Mal’tseva ◽  
D. Meyerstein
Keyword(s):  
Silver Nanoparticles ◽  
Hydrogen Oxidation ◽  
Catalytic Hydrogen ◽  
Zeolite Rho

Experimental assessment of a catalytic hydrogen oxidation system for the off-gas processing of the ITER WDS

2013 ◽  
Vol 88 (9-10) ◽  
pp. 2332-2335
Author(s):  
C. Plusczyk ◽  
N. Bekris ◽  
I. Cristescu ◽  
N. Lohr ◽  
R. Michling ◽  
...  
Keyword(s):  
Hydrogen Oxidation ◽  
Experimental Assessment ◽  
Gas Processing ◽  
Catalytic Hydrogen ◽  
Oxidation System

scholarly journals Grain-boundary-rich Pt nanoparticle assembly for catalytic hydrogen sensing at room temperature

2021 ◽  
Author(s):  
LONG LUO ◽  
Xin Geng ◽  
Shuwei Li ◽  
Jaeyoung Heo ◽  
Yi Peng ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Platinum Nanoparticles ◽  
High Performance ◽  
Room Temperature ◽  
Hydrogen Oxidation ◽  
Water Electrolysis ◽  
Nanoparticle Assembly ◽  
Platinum Nanoparticle ◽  
Hydrogen Sensing ◽  
Catalytic Hydrogen

We report a facile method of synthesizing grain-boundary(GB)-rich platinum nanoparticle assembly. GBs are formed between platinum nanoparticles during their random collision and attachment in solution driven by water electrolysis. The GB-rich nanoparticle assembly exhibits ~400-fold higher catalytic hydrogen oxidation rate than platinum nanoparticles before assembly, enabling catalytic hydrogen sensing at room temperature without external heating. Our sensor also demonstrates fast response/recovery (~7 s at >1% H2), nearly no signal variation during a 280-hour-long stability test, and high selectivity toward hydrogen over 36 interference gases. Furthermore, this sensor can be easily fabricated from commercial thermometers at a low cost (< $5 per unit). Theoretical calculation results reveal that the high performance of GB-rich platinum nanoparticle assembly arises from tensile strain at the GBs.

scholarly journals Resolving multifrequential oscillations and nanoscale interfacet communication in single-particle catalysis

Science ◽  
2021 ◽  
pp. eabf8107
Author(s):  
Y. Suchorski ◽  
J. Zeininger ◽  
S. Buhr ◽  
M. Raab ◽  
M. Stöger-Pollach ◽  
...  
Keyword(s):  
Single Particle ◽  
Active Sites ◽  
Hydrogen Oxidation ◽  
Frequency Locking ◽  
Spatial Coupling ◽  
Reaction Fronts ◽  
Catalytic Hydrogen ◽  
Field Electron Microscopy ◽  
The Individual ◽  
Oscillation Frequencies

In heterogeneous catalysis research, the reactivity of the individual nanofacets of single particle is typically not resolved. We applied in situ field electron microscopy (FEM) to the apex of a curved rhodium crystal (radius of 650 nanometers), providing high spatial (~2 nanometers) and time resolution (~2 ms) of oscillatory catalytic hydrogen oxidation, imaging adsorbed species and reaction fronts on the individual facets. Using ionized water as imaging species, the active sites were directly imaged by field ion microscopy (FIM). The catalytic behavior of differently structured nanofacets and the extent of coupling between them were monitored individually. We observed limited interfacet coupling, entrainment, frequency-locking, and reconstruction-induced collapse of spatial coupling. The experimental results are backed-up by microkinetic modelling of time-dependent oxygen species coverages and oscillation frequencies.

scholarly journals Coexisting multi-states in catalytic hydrogen oxidation on rhodium

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
P. Winkler ◽  
J. Zeininger ◽  
M. Raab ◽  
Y. Suchorski ◽  
A. Steiger-Thirsfeld ◽  
...  
Keyword(s):  
Steady State ◽  
Hydrogen Oxidation ◽  
Kinetic Modelling ◽  
Mean Field ◽  
Photoemission Spectroscopy ◽  
Spatially Resolved ◽  
Catalytically Active ◽  
Catalytic Hydrogen ◽  
Experimental Findings ◽  
General Possibility

AbstractCatalytic hydrogen oxidation on a polycrystalline rhodium foil used as a surface structure library is studied by scanning photoelectron microscopy (SPEM) in the 10−6 mbar pressure range, yielding spatially resolved X-ray photoemission spectroscopy (XPS) measurements. Here we report an observation of a previously unknown coexistence of four different states on adjacent differently oriented domains of the same Rh sample at the exactly same conditions. A catalytically active steady state, a catalytically inactive steady state and multifrequential oscillating states are simultaneously observed. Our results thus demonstrate the general possibility of multi-states in a catalytic reaction. This highly unusual behaviour is explained on the basis of peculiarities of the formation and depletion of subsurface oxygen on differently structured Rh surfaces. The experimental findings are supported by mean-field micro-kinetic modelling. The present observations raise the interdisciplinary question of how self-organising dynamic processes in a heterogeneous system are influenced by the permeability of the borders confining the adjacent regions.

Dihydrogen complexes of metalloporphyrins: characterization and catalytic hydrogen oxidation activity. [Erratum to document cited in CA117(4):34433t]

1993 ◽  
Vol 115 (11) ◽  
pp. 4947-4947 ◽  
Author(s):  
James P. Collman ◽  
Paul S. Wagenknecht ◽  
James E. Hutchison ◽  
Nathan S. Lewis ◽  
Michel Angel Lopez ◽  
...  
Keyword(s):  
Hydrogen Oxidation ◽  
Oxidation Activity ◽  
Dihydrogen Complexes ◽  
Catalytic Hydrogen
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