.png){kind=icon}
.png){kind=icon}
Return
Switching Photocatalytic NH3 Oxidation Pathways from NOx to N2 via Synergistic Kineto-Thermodynamic Modulation on TiO2
.png){kind=icon}
PRE
AI
G
H
Y
B
K
M
R
Q
L
Q
H
DOI：10.1021/acs.est.6c05180.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
The escalating demand for ammonia (NH3) as a promising energy vector and essential chemical raw material in both industrial and agricultural applications, coupled with its noxious and caustic properties, has led to significant atmospheric emissions that pose environmental and health risks. Photocatalytic NH3 oxidation over TiO2 is a promising strategy for air purification but is hindered by poor selectivity, often leading to the formation of toxic NOx byproducts due to the complex reaction network involving multiple competing pathways and intermediates. This study addresses this selectivity issue by designing a modified TiO2 photocatalyst through a synergistic defect-dopant engineering approach. Through controlled doping and defect engineering, we demonstrate that N doping and OVs distinctly modulate the reaction mechanism and products’ selectivity. Nitrogen doping thermodynamically promotes N2 formation by stabilizing NH2 intermediates and facilitating their selective coupling with NO, whereas OVs kinetically facilitate NH3 and O2 dissociation, promoting superoxide-mediated oxidation, leading to overoxidized products such as NOx and nitrate/nitrite HNOx– species. An optimal N-doped TiO2 catalyst achieves 87% NH3 conversion with 80% N2 selectivity and minimal NOx emission (∼5 ppm), while exhibiting excellent stability over multiple cycles. This work elucidates a defect-dopant strategy that optimizes kinetic and thermodynamic aspects of NH3 oxidation, providing a design principle for selective photocatalytic nitrogen management toward sustainable air purification.
Keywords:
ammonia photocatalytic oxidation
N2/HNOx selectivity
N-doped TiO2
oxygen vacancy
selective oxidation pathways
Journal
E
IF:
11.3
Papers:
1.9K
Citations:
1
Organization
Cited Papers