Low-temperature heat capacity and standard entropy of PdO(cr.)

Смирнова, Н. Н.; Быкова, Т. А.; Polotnyanko, N. A.; Shikina, N. D.; Khodakovskii, I. L.

doi:10.1134/s0036024410110051

Cited by 13 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(1)–(3)] at 300 °C. Constant heats of reaction and validity of short‐cut van't Hoff's equation were assumed; the thermodynamic properties at 298.15 K for Al(OH) 3 are from, for Sn(OH) 2 are from, for Pd(OH) 2 are from

true normalR 1) . 2 / 3 Al (OH)_{3} \vec{\leftarrow} 1 / 3 Al_{2} normalO_{3} + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 36 kJ / mol_{normalH 2 normalO}

true normalR 2) . Pd (OH)_{2} \vec{\leftarrow} PdO + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 25 kJ / mol_{normalH 2 normalO}

true normalR 3) . Sn (OH)_{2} \vec{\leftarrow} SnO + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 19 kJ / mol_{normalH 2 normalO}

…”

Section: Resultsmentioning

confidence: 99%

“…Constant heats of reaction and validity of short-cut van't Hoff's equation were assumed; the thermody-namic properties at 298.15 K for Al(OH) 3 are from, [45] for Sn(OH) 2 are from, [46] for Pd(OH) 2 are from. [47,48] R1Þ: 2=3AlðOHÞ 3 (3) The dehydroxylation trend indicates that the hydroxylated inactive Pd(OH) 2 may coexist with dehydroxylated Al 2 O 3 , while in the Pd/SnO 2 system SnO can potentially serve as a sink for water released from Pd(OH) 2 , followed by Sn(OH) 2 dehydroxylation, which potentially can explain the speciation observed in Figure 5.…”

Section: In Situ Xas: Sn L 3 Edge During Wet Methane Combustionmentioning

confidence: 99%

See 1 more Smart Citation

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃

Barrett

Shen

et al. 2019

ChemCatChem

View full text Add to dashboard Cite

Quantitative analysis of poisonous Pd hydroxide phase formation during methane combustion in the presence of water is performed via in situ X‐ray absorption spectroscopy from 200 to 500 deg C for palladium catalysts supported on tin and aluminum oxides. Water presence inhibits oxidation of the metallic Pd; for the Pd/Al2O3 catalyst the major oxidation product is Pd(OH)2, with PdO being the dominant phase on the Pd/SnO2 system. Tin dioxide is reduced during methane oxidation in the presence of water, regardless of the excess oxygen in the feed. Temperature‐programmed surface reactions at anaerobic and low‐oxygen conditions revealed that the Pd/SnO2 catalyst has an inability to catalyze methane steam reforming, as opposed to Pd/Al2O3. We suggest that tin oxide extracts hydroxyls from the PdO surface, which makes the latter more active in methane combustion in the presence of water but inactive in methane steam reforming.

show abstract

true normalR 1) . 2 / 3 Al (OH)_{3} \vec{\leftarrow} 1 / 3 Al_{2} normalO_{3} + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 36 kJ / mol_{normalH 2 normalO}

true normalR 2) . Pd (OH)_{2} \vec{\leftarrow} PdO + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 25 kJ / mol_{normalH 2 normalO}

true normalR 3) . Sn (OH)_{2} \vec{\leftarrow} SnO + normalH_{2} normalO Δ normalG^{\circ}_{573 normalK} = - 19 kJ / mol_{normalH 2 normalO}

…”

Section: Resultsmentioning

confidence: 99%

Section: In Situ Xas: Sn L 3 Edge During Wet Methane Combustionmentioning

confidence: 99%

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃

Barrett

Shen

et al. 2019

ChemCatChem

View full text Add to dashboard Cite

show abstract

“…The solubility of crystalline PdO at 298.15 K has been predicted to be lower than that of amorphous PdO by 1.6 orders of magnitude . The equilibrium Pd concentrations resulting from dissolution of amorphous PdO at neutral or basic pH were determined to be 10 ppb .…”

Section: Resultsmentioning

confidence: 98%

“…A similar positive shift in the potential of Peak I was observed following a comparable immersion in deionized water (Figure ). Depending on whether or not the surface PdO is crystalline or amorphous, this dissolution reaction may proceed according to either eq or eq below PdO false( cr false) + 2 normalH + → Pd 2 + + normalH 2 normalO PdO · normalH 2 normalO false( amorph false) + 2 normalH + → Pd 2 + + 2 normalH 2 normalO …”

Section: Resultsmentioning

confidence: 99%

“…The solubility of crystalline PdO at 298.15 K has been predicted to be lower than that of amorphous PdO by 1.6 orders of magnitude. 28 The equilibrium Pd concentrations resulting from dissolution of amorphous PdO at neutral or basic pH were determined to be 10 ppb. 29 Hence, the Pd concentrations observed in this work (4 ± 1 ppb) are intermediate between those predicted for fully crystalline PdO and those observed in the case of fully amorphous PdO, suggesting that the oxide films on the sputtered Pd films used in this work may possess both crystalline and amorphous character.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Mechanism of 2-Mercaptoethanesulphonate Adsorption onto Sputtered Palladium Films: Influence of Surface Oxide Species

et al. 2012

View full text Add to dashboard Cite

A method is presented whereby the adsorption of 2-mercaptoethanesulphonate (MESA) onto Pd may be quantified using the peak separation of a cyclic voltammogram of potassium ferricyanide measured following sequential treatment of the Pd surface with MESA and 1-dodecanethiol. The observed kinetics of MESA adsorption onto sputtered Pd were slower than those observed on sputtered Au by 3−4 orders of magnitude. The rate of MESA adsorption onto a freshly polished Pd disk electrode was comparable to, but slower than, that onto sputtered Au. The lower rate of MESA coating observed on sputtered Pd as compared with sputtered Au was attributed to the presence of oxide species on the former. The rate of MESA coating on Pd was found to decrease with increasing oxide surface coverage. Rate constants were calculated using the method of initial rate as 4 × 10 −2 s −1 for Au and 8 × 10 −5 and 8 × 10 −6 s −1 for Pd with 0.5 and 0.7 fractional surface coverage of PdO, respectively. The kinetics of MESA coating onto Pd were rationalized in terms of the removal of surface oxide species. Specifically, linear sweep voltammetry revealed that the amount of metallic Pd at the surface increased with coating time through two distinct mechanisms. First, metallic Pd was formed through oxide dissolution. Second, metallic Pd was formed through reaction of adsorbed oxygen species with MESA. Measurements of Pd concentration in the coating solution using ICP-MS were consistent with the oxide films on the sputtered Pd films possessing both crystalline and amorphous character. In the case of sputtered Pd films, an increase in the crystalline character of the film may occur coincidently with an increase in oxide surface coverage.

show abstract

Effect of Hydrogen on the Internal Oxidation of a Pd–Cr Alloy in Dual-Atmosphere Conditions

et al. 2022

View full text Add to dashboard Cite

The effect of hydrogen on oxygen permeability has been studied in a diluted Pd–Cr alloy in dual- and single- atmosphere conditions between 600 and 950 °C. The 0.3 mm thick Pd–1.5Cr foil was exposed in dry and humid air as well as in dual-atmosphere conditions, with one sample surface being exposed to air and one to hydrogen, as encountered in solid oxide fuel cells. At all temperatures, Cr oxidized internally forming internal oxidation zones which were measured in metallographic cross sections. Below 800 °C, an external layer of PdO formed on the surface decreasing the internal oxidation kinetics. No measurable effect of hydrogen on the internal oxidation of Cr in Pd has been detected.

show abstract

Low-temperature heat capacity and standard entropy of PdO(cr.)

Cited by 13 publications

References 13 publications

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃

Mechanism of 2-Mercaptoethanesulphonate Adsorption onto Sputtered Palladium Films: Influence of Surface Oxide Species

Effect of Hydrogen on the Internal Oxidation of a Pd–Cr Alloy in Dual-Atmosphere Conditions

Contact Info

Product

Resources

About

Low-temperature heat capacity and standard entropy of PdO(cr.)

Cited by 13 publications

References 13 publications

Understanding the Role of SnO2 Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)2 and Comparison with Pd/Al2O3

Understanding the Role of SnO2 Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)2 and Comparison with Pd/Al2O3

Mechanism of 2-Mercaptoethanesulphonate Adsorption onto Sputtered Palladium Films: Influence of Surface Oxide Species

Effect of Hydrogen on the Internal Oxidation of a Pd–Cr Alloy in Dual-Atmosphere Conditions

Contact Info

Product

Resources

About

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃

Understanding the Role of SnO₂ Support in Water‐Tolerant Methane Combustion: In situ Observation of Pd(OH)₂ and Comparison with Pd/Al₂O₃