Low-Temperature Infrared Spectroscopy of Surface Species

Author(s):  
Alexey Tsyganenko
Author(s):  
Ahmed Eid ◽  
Mohammad Aminur Rahman ◽  
Hind A. Al-Abadleh

Nitrogen oxides (NOx) emissions from high temperature combustion processes under fuel-lean conditions continue to be a challenge for the energy industry. Selective catalytic reduction (SCR) has been possible with metal oxides and zeolites. There is still the need to identify catalytic materials that are efficient in reducing NOx to environmentally benign nitrogen gas at temperatures lower than 200°C. Metal-organic frameworks (MOFs) emerged as a class of highly porous materials with unique physical and chemical properties. This study is motivated by the lack of systematic investigations on SCR using MOFs under industrially-relevant conditions. Here, we investigate the extent of NO conversion with two commercially-available MOFs; Basolite F300 (Fe-BTC) and HKUST-1 (Cu-BTC), mixed with solid urea as a source for the reductant, ammonia gas. For comparison, experiments were also conducted using cobalt ferrite (CoFe2O4) as a non-porous counterpart to relate its reactivity to those obtained from MOFs. Fourier-transform infrared spectroscopy (FTIR) was utilized to identify gas and surface species the temperature range 115 -180°C. Computational analysis was performed using Monte Carlo (MC) simulations to quantify adsorption energies of different surface species. The results show that the rate of ammonia production from the in situ solid urea decomposition was higher using CoFe2O4 than Fe-BTC and Cu-BTC, and that there is very limited conversion of NO on the mixed solid urea-MOF systems due to site blocking. The main conclusions from this study is that MOFs have limited abilities in converting NO under low temperature conditions, and that surface regeneration requires additional experimental steps.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3089
Author(s):  
Peilei Zhou ◽  
Wensheng Wang ◽  
Lili Zhu ◽  
Haoyun Wang ◽  
Yongming Ai

This study aims to investigate the performance evolution and mechanism of asphalt under action of chloride salt erosion. Asphalt samples soaked with five different snow melting chloride salt concentrations were taken as the research object. Then, the high-temperature performance, low-temperature performance, temperature sensitivity and asphalt–aggregate adhesion property of asphalt samples were carried out. Additionally, Fourier transform infrared spectroscopy (FTIR) was used to explore the mechanism of chloride salt erosion on asphalt. Test results showed the linear variation relationships of high-temperature performance, low-temperature performance and temperature sensitivity with chloride salt concentrations. The high-temperature performance of asphalt would be improved by chloride snowmelt salt. With the increase in the chloride salt solution concentration, the low-temperature performance of asphalt became worse, and the temperature sensitivity increased. Moreover, after the effect of the chloride salt solution, the asphalt–aggregate adhesion property decreased with the increase in the chloride salt solution concentration. It is necessary to control the amount of chloride snowmelt salt in the actual snow removal projects. Finally, based on Fourier transform infrared spectroscopy, the mechanism of chloride salt erosion on asphalt was preliminarily explored. With the increase in the chloride salt solution concentration, the proportion of light components (saturated fraction, aromatic fraction) in asphalt decreased, and the proportion of heavy components (resin and asphaltene) with good thermal stability increased.


2016 ◽  
Vol 259 ◽  
pp. 19-26 ◽  
Author(s):  
Alan J. McCue ◽  
Greg A. Mutch ◽  
Andrew I. McNab ◽  
Steven Campbell ◽  
James A. Anderson

2007 ◽  
Vol 5 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Abdülhadi Baykal ◽  
Yüksel Köseoğlu ◽  
Mehmet Şenel

AbstractHeating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements confirm a typical Mn2+signal with a highly resolved hyperfine structure.


Nanoscale ◽  
2021 ◽  
Author(s):  
wei Lv ◽  
hanchao Teng ◽  
chenchen Wu ◽  
Xiaotao Zhang ◽  
Xiangdong Guo ◽  
...  

Nanoscale Fourier transforms infrared spectroscopy (nano-FTIR) based on scanning probe microscopy enables identification of chemical composition and structure of surface species with a high spatial resolution (~10 nm), which is...


2018 ◽  
Vol 8 (24) ◽  
pp. 6360-6374 ◽  
Author(s):  
Thanh Huyen Vuong ◽  
Stephan Bartling ◽  
Ursula Bentrup ◽  
Henrik Lund ◽  
Jabor Rabeah ◽  
...  

Inserting adjacent Mn3+/Mn2+ and VO3+/VO2+ redox couples in Ce1−xTixO2 improves catalytic performance.


Sign in / Sign up

Export Citation Format

Share Document