Thoughts on the use of gold-based catalysts in environmental protection catalysis

Scurrell, Michael S.

doi:10.1007/s13404-017-0194-z

Cited by 24 publications

(10 citation statements)

References 46 publications

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“…Most of the CO emission occurs when the engine is still cold [1]. Gold is the most active catalyst for CO oxidation at room temperature which makes Au catalysts very interesting for this application [2][3][4][5][6]. However, when the engine becomes hot, it reaches the temperatures as high as 700°C, and high-temperature treatment often causes growth of Au nanoparticles [7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of oxide-supported gold nanoparticles

et al. 2019

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In this study, we report on the influence of support and gas atmosphere on the thermal stability of Au nanoparticles on oxidic supports. All samples were prepared with a modified impregnation method and have initial Au particle sizes in the range of 3-4 nm. We observed that in air, Au nanoparticles on SiO 2 and Al 2 O 3 are thermally much more stable than Au nanoparticles on TiO 2. For instance, upon treatment up to 700°C, on SiO 2 , Au particles grew from 4 to 6 nm while on TiO 2 from 3 to 13 nm. For Au nanoparticles on TiO 2 , growth is accelerated by oxidizing atmospheres and the presence of water and/or chloride. On nonreducible supports and in non-oxidizing atmosphere, the supported Au nanoparticles were remarkably stable. The insight into the growth of oxide-supported Au nanoparticles in reactive atmosphere offers an additional tool for a rational choice of a support for high-temperature gas-phase reactions involving gold nanocatalysts.

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Section: Introductionmentioning

confidence: 99%

Thermal stability of oxide-supported gold nanoparticles

et al. 2019

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“…Supported highly dispersed gold attracts a lot of attention as a catalyst-the properties of which could be better than those of the dispersed Pt-group metals. Scurrell [1] noted that gold recovery is to a large extent much easier than that of Pt-group metals. These factors can make the economics of using expensive gold rather than the Pt-group metals attractive.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Production from Formic Acid over Au Catalysts Supported on Carbon: Comparison with Au Catalysts Supported on SiO2 and Al2O3

et al. 2019

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Characteristics and catalytic activity in hydrogen production from formic acid of Au catalysts supported on porous N-free (Au/C) and N-doped carbon (Au/N-C) have been compared with those of Au/SiO2 and Au/Al2O3 catalysts. Among the catalysts examined, the Au/N-C catalyst showed the highest Au mass-based catalytic activity. The following trend was found at 448 K: Au/N-C > Au/SiO2 > Au/Al2O3, Au/C. The trend for the selectivity in hydrogen production was different: Au/C (99.5%) > Au/Al2O3 (98.0%) > Au/N-C (96.3%) > Au/SiO2 (83.0%). According to XPS data the Au was present in metallic state in all catalysts after the reaction. TEM analysis revealed that the use of the N-C support allowed obtaining highly dispersed Au nanoparticles with a mean size of about 2 nm, which was close to those for the Au catalysts on the oxide supports. However, it was by a factor of 5 smaller than that for the Au/C catalyst. The difference in dispersion could explain the difference in the catalytic activity for the carbon-based catalysts. Additionally, the high activity of the Au/N-C catalyst could be related to the presence of pyridinic type nitrogen on the N-doped carbon surface, which activates the formic acid molecule forming pyridinium formate species further interacting with Au. This was confirmed by density functional theory (DFT) calculations. The results of this study may assist the development of novel Au catalysts for different catalytic reactions.

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“…Due to the scarcity of these metals, increasing prices and health hazards, it is a requirement to find a replacement which is less rare, less expensive, and competitively active. Over time, many pure metals and metal oxides were tested as alternatives to these PGEs for redox reactions in catalytic converters i.e., Au, Ni, Cu, MnO 2 , CoO, Co 3 O 4 and CuO [15,[17][18][19]. Co 3 O 4 over different supports was investigated as a catalyst for oxidation of CO and HC in exhaust emission control system and demonstrated low temperature activity [20,21].…”

Section: Introductionmentioning

confidence: 99%

Effect of Zirconia on Hydrothermally Synthesized Co3O4/TiO2 Catalyst for NOx Reduction from Engine Emissions

2020

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Effect of zirconia on the 6 wt.% Co3O4/TiO2 catalyst for NOx reduction is investigated in this paper. Co3O4/TiO2 catalyst was prepared by using hydrothermal method and then was promoted with zirconia by impregnation to get 8% wt. ZrO2-Co3O4/TiO2 catalyst. Catalysts were characterized by using XRD, SEM, and TGA. Catalysts real time activity was tested by coating them on stainless steel wire meshes, containing them in a mild steel shell and mounting them at the exhaust tailpipe of a 72 cm3 motorcycle engine. Zirconia promoted catalyst showed higher conversion efficiency of NOX than the simple Co3O4/TiO2 catalyst due to small crystalline size, fouling inhibition and thermal stability.

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Thoughts on the use of gold-based catalysts in environmental protection catalysis

Cited by 24 publications

References 46 publications

Thermal stability of oxide-supported gold nanoparticles

Thermal stability of oxide-supported gold nanoparticles

Hydrogen Production from Formic Acid over Au Catalysts Supported on Carbon: Comparison with Au Catalysts Supported on SiO2 and Al2O3

Effect of Zirconia on Hydrothermally Synthesized Co3O4/TiO2 Catalyst for NOx Reduction from Engine Emissions

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