Oxygen vacancies as active sites for H2S dissociation on the rutile TiO2(110) surface: a first-principles study

2016 ◽  
Vol 18 (9) ◽  
pp. 6706-6712 ◽  
Author(s):  
Fang Wang ◽  
Shiqian Wei ◽  
Zhi Zhang ◽  
Great R. Patzke ◽  
Ying Zhou
Keyword(s):  
First Principles ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Active Surface ◽  
Energy Barriers ◽  
Rutile Tio2 ◽  
Surface Sites ◽  
First Principles Study ◽  
Active Surface Sites

Bridged oxygen vacancies act as active surface sites markedly reducing the energy barriers for the paths along H2S dissociation on the rutile TiO2(110) surface.

scholarly journals Irreversible loss of ice nucleation active sites in mineral dust particles caused by sulphuric acid condensation

2010 ◽  
Vol 10 (23) ◽  
pp. 11471-11487 ◽  
Author(s):  
R. C. Sullivan ◽  
M. D. Petters ◽  
P. J. DeMott ◽  
S. M. Kreidenweis ◽  
H. Wex ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Active Sites ◽  
Mineral Dust ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Ammonia Gas ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Acid Coating

Abstract. During the FROST-2 (FReezing Of duST) measurement campaign conducted at the Leipzig Aerosol Cloud Interaction Simulator (LACIS), we investigated changes in the ice nucleation properties of 300 nm Arizona Test Dust mineral particles following thermochemical processing by varying amounts and combinations of exposure to sulphuric acid vapour, ammonia gas, water vapour, and heat. The processed particles' heterogeneous ice nucleation properties were determined in both the water subsaturated and supersaturated humidity regimes at −30 °C and −25 °C using Colorado State University's continuous flow diffusion chamber. The amount of sulphuric acid coating material was estimated by an aerosol mass spectrometer and from CCN-derived hygroscopicity measurements. The condensation of sulphuric acid decreased the dust particles' ice nucleation ability in proportion to the amount of sulphuric acid added. Heating the coated particles in a thermodenuder at 250 °C – intended to evaporate the sulphuric acid coating – reduced their freezing ability even further. We attribute this behaviour to accelerated acid digestion of ice active surface sites by heat. Exposing sulphuric acid coated dust to ammonia gas produced particles with similarly poor freezing potential; however a portion of their ice nucleation ability could be restored after heating in the thermodenuder. In no case did any combination of thermochemical treatments increase the ice nucleation ability of the coated mineral dust particles compared to unprocessed dust. These first measurements of the effect of identical chemical processing of dust particles on their ice nucleation ability under both water subsaturated and mixed-phase supersaturated cloud conditions revealed that ice nucleation was more sensitive to all coating treatments in the water subsaturated regime. The results clearly indicate irreversible impairment of ice nucleation activity in both regimes after condensation of concentrated sulphuric acid. This implies that the sulphuric acid coating caused permanent chemical and/or physical modification of the ice active surface sites; the possible dissolution of the coating during droplet activation did not restore all immersion/condensation-freezing ability.

First-principles study on the mechanism of photocatalytic reduction of nitrobenzene on the rutile TiO2(110) surface

2020 ◽  
Vol 22 (3) ◽  
pp. 1187-1193 ◽  
Author(s):  
Yongfei Ji ◽  
Ting Fan ◽  
Yi Luo
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
Photocatalytic Reduction ◽  
Rutile Tio2 ◽  
First Principles Study ◽  
Excess Electrons

Oxygen vacancies and excess electrons play vital roles in the photocatalytic reduction of nitrobenzene on the TiO2 surface.

scholarly journals Irreversible loss of ice nucleation active sites in mineral dust particles caused by sulphuric acid condensation

2010 ◽  
Vol 10 (7) ◽  
pp. 16901-16940 ◽  
Author(s):  
R. C. Sullivan ◽  
M. D. Petters ◽  
P. J. DeMott ◽  
S. M. Kreidenweis ◽  
H. Wex ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Active Sites ◽  
Mineral Dust ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Ammonia Gas ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Acid Coating

Abstract. During the FROST-2 (FReezing Of duST) measurement campaign conducted at the Leipzig Aerosol Cloud Interaction Simulator (LACIS), we investigated changes in the ice nucleation properties of 300 nm Arizona test dust mineral particles following thermochemical processing by varying amounts and combinations of exposure to sulphuric acid vapour, ammonia gas, water vapour, and heat. The processed aerosol's heterogeneous ice nucleation properties were determined in both the water subsaturated and supersaturated humidity regimes at −30 °C and −25 °C using Colorado State University's continuous flow diffusion chamber. The amount of sulphuric acid coating material was estimated by an aerosol mass spectrometer and from CCN-derived hygroscopicity measurements. The condensation of sulphuric acid decreased the dust particles' ice nucleation ability in proportion to the amount of sulphuric acid added. Heating the coated particles in a thermodenuder at 250 °C – intended to evaporate the sulphuric acid coating – reduced their freezing ability even further. We attribute this behaviour to accelerated acid digestion of ice active surface sites by heat. Exposing sulphuric acid coated dust to ammonia gas produced particles with similarly poor freezing potential; however a portion of their ice nucleation ability could be restored after heating in the thermodenuder. In no case did any combination of thermochemical treatments increase the ice nucleation ability of the coated mineral dust particles compared to unprocessed dust. These first measurements of the effect of identical chemical processing of dust particles on their ice nucleation ability in both water subsaturated and mixed-phase supersaturated cloud conditions revealed that ice nucleation was more sensitive to all coating treatments in the water subsaturated regime. The results clearly indicate irreversible impairment of ice nucleation activity in both regimes after condensation of concentrated sulphuric acid. This implies that the sulphuric acid coating caused permanent chemical and/or physical modification of the ice active surface sites; the possible dissolution of the coating during droplet activation did not restore all immersion/condensation-freezing ability.

scholarly journals Importance of Surface Topography in Both Biological Activity and Catalysis of Nanomaterials: Can Catalysis by Design Guide Safe by Design?

2021 ◽  
Vol 22 (15) ◽  
pp. 8347
Author(s):  
Mary Gulumian ◽  
Charlene Andraos ◽  
Antreas Afantitis ◽  
Tomasz Puzyn ◽  
Neil J. Coville
Keyword(s):  
Physicochemical Property ◽  
Surface Topography ◽  
Surface Area ◽  
Surface Properties ◽  
Active Sites ◽  
Active Surface ◽  
Predictive Toxicology ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Safe By Design

It is acknowledged that the physicochemical properties of nanomaterials (NMs) have an impact on their toxicity and, eventually, their pathogenicity. These properties may include the NMs’ surface chemical composition, size, shape, surface charge, surface area, and surface coating with ligands (which can carry different functional groups as well as proteins). Nanotopography, defined as the specific surface features at the nanoscopic scale, is not widely acknowledged as an important physicochemical property. It is known that the size and shape of NMs determine their nanotopography which, in turn, determines their surface area and their active sites. Nanotopography may also influence the extent of dissolution of NMs and their ability to adsorb atoms and molecules such as proteins. Consequently, the surface atoms (due to their nanotopography) can influence the orientation of proteins as well as their denaturation. However, although it is of great importance, the role of surface topography (nanotopography) in nanotoxicity is not much considered. Many of the issues that relate to nanotopography have much in common with the fundamental principles underlying classic catalysis. Although these were developed over many decades, there have been recent important and remarkable improvements in the development and study of catalysts. These have been brought about by new techniques that have allowed for study at the nanoscopic scale. Furthermore, the issue of quantum confinement by nanosized particles is now seen as an important issue in studying nanoparticles (NPs). In catalysis, the manipulation of a surface to create active surface sites that enhance interactions with external molecules and atoms has much in common with the interaction of NP surfaces with proteins, viruses, and bacteria with the same active surface sites of NMs. By reviewing the role that surface nanotopography plays in defining many of the NMs’ surface properties, it reveals the need for its consideration as an important physicochemical property in descriptive and predictive toxicology. Through the manipulation of surface topography, and by using principles developed in catalysis, it may also be possible to make safe-by-design NMs with a reduction of the surface properties which contribute to their toxicity.

Oxygen vacancies induced ferromagnetic behaviors in Co3O4–: An experimental and first-principles study

2018 ◽  
Vol 660 ◽  
pp. 287-293 ◽  
Author(s):  
P. Wang ◽  
C. Jin ◽  
P. Li ◽  
D.X. Zheng ◽  
J.L. Gong ◽  
...  
Keyword(s):  
First Principles ◽  
Oxygen Vacancies ◽  
First Principles Study

Etching-Assisted Route to Heterophase Au Nanowires with Multiple Types of Active Surface Sites for Silane Oxidation

Nano Letters ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 6363-6369 ◽  
Author(s):  
Chaoqi Wang ◽  
Xiang Li ◽  
Lei Jin ◽  
Peng-Han Lu ◽  
Catherine Dejoie ◽  
...  
Keyword(s):  
Active Surface ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Au Nanowires

Single Ru Sites-Embedded Rutile TiO2 Catalyst for Non-Oxidative Direct Conversion of Methane: A First-Principles Study

2019 ◽  
Vol 123 (23) ◽  
pp. 14391-14397 ◽  
Author(s):  
Xiufang Ma ◽  
Keju Sun ◽  
Jin-Xun Liu ◽  
Wei-Xue Li ◽  
Xingmin Cai ◽  
...  
Keyword(s):  
First Principles ◽  
Direct Conversion ◽  
Rutile Tio2 ◽  
Tio2 Catalyst ◽  
First Principles Study ◽  
Conversion Of Methane
Sign in / Sign up

Export Citation Format

Share Document