increasing the selectivity of dennox photocatalysts and
TRANSCRIPT
Increasing the Selectivity of DeNIncreasing the Selectivity of DeNIncreasing the Selectivity of DeNS i h E l i f TSuppressing the Evolution of ToxSuppressing the Evolution of Toxpp gJ. Patzsch, J. Z. Bloh| e‐mail: [email protected]| BMWi via AiF| PeriodJ. Patzsch, J. Z. Bloh| e mail: [email protected]| BMWi via AiF| Period
h lPhotocatalysisPhotocatalysis• Reduction of O2 to superoxide 2 p
• Oxidation of water to ∙OH by V• Oxidation of water to OH by V
O H O d OH idi• O2∙‐, H2O2 and ∙OH can oxidize 2 2 2
• Removal of NO3‐ from the surfRemoval of NO3 from the surf
• Adsorbed NO ‐ can be re‐reduc• Adsorbed NO3 can be re‐reduc‐
electronselectrons
R d i i i i• Re‐reduction in competition w
• Co‐Catalysts support the full oy pp
and suppress the back reactionand suppress the back reaction
Influence of iron graftingInfluence of iron grafting
• Up to 120 % hig• Up to 120 % higOptimum concentration for P25:
Th l f N
p
• The release of N0 003 to 0 1 mol% iron
h l
0.003 to 0.1 mol% iron
• Higher toleranc10 to 400 Fe3+/particle g10 to 400 Fe3 /particle
• Higher possibleHigher possible
Environmentally relevant mixture of NO NO and OEnvironmentally relevant mixture of NO, NO2 and O3NO NO NO O NO NO
200
NO NO2 NO
x O
3
200
NO NO
200 200
150 150150
ppb
150
pb]
n / p
n [p
p
100atio
n
100atio
n
100
entr
a 100
entr
a
once
once
Co
Co
50 50
0 7 1 7 2 70
0 0 0 2 0 4 0 60
0,7 1,7 2,7
time [h]
0,0 0,2 0,4 0,6
titime [h] ti
U difi d P25Unmodified P25: P25 grafted with jug j
• Low activity for NOx degradation (8%) • Degradation of Ny x g ( ) Degradation of N
• NO is mainly converted to NO2 • High NO degradNO is mainly converted to NO2 • High NOx degrad
• NO is increased by 40% • 40% decrease in• NO2 is increased by 40%. • 40% decrease in
Hi hli hHighlighHighligh201720172017
Chemical TechnologyChemical Technology
NOx Photocatalysts andNOx Photocatalysts andNOx Photocatalysts and i B P dxic By‐Productsxic By‐Productsy
d: 01.06.2015‐31.08.2017d: 01.06.2015 31.08.2017
1 2Measurements
1 2Measurements
or H2O2 by CB electrons2 2 y• Based on the ISO
VB holesBased on the ISO
VB holesstandard 22197 1
O h istandard 22197‐1
NOx to the nitrate G fl f 3 L/ ix • Gas flow of 3 L/minface by rain
/ ²face by rain
• UV light of 1 mW/cm²ced to NO by CB
g /ced to NO2 by CB • 50 % relative humidity50 % relative humidity
• 1 ppm NO or 1 ppm Oi h O d i
• 1 ppm NO or 1 ppm O3
with O2 reduction • Aeroxide P25 (Evonik)2 • Aeroxide P25 (Evonik)xidation to nitrate
n from nitraten from nitrate
33
gher selectivity and 110 % activity by modification with Fe3+gher selectivity and 110 % activity by modification with Fe3
NO i d ti ll d l d d l h ft l tiNO2 is drastically delayed and only happens after long exposure times
d h h h l d f h lce towards nitrate poisoning, the high selectivity is retained for a much longer timep g g y g
e nitrate accumulation on the surfacee nitrate accumulation on the surface
4 5Summary & Literature
4 5Summary & Literature
hl l d h l bO NO O
• Highly selective and active photocatalyst by O
2 NO
x O
3 g y p y y
grafting of low amounts of iron on the surfacegrafting of low amounts of iron on the surface
• Long term stable materials against catalyst• Long term stable materials against catalyst
poisoning of nitratepoisoning of nitrate
Si ifi d d i f NO NO d• Significant degradation of NO, NO2 and ozone 2
in environmentally relevant mixtures y
0 8 1 0 1 2 1 4 1 6
• J Patzsch J Z Bloh Catal Today accepted0,8 1,0 1,2 1,4 1,6
ime [h] • J. Patzsch, J. Z. Bloh, Catal. Today, accepted ime [h]
(201 )(2017)ust 0.04 mol% Fe:
• J. Patzsch, A. Folli, D. MacPhee, J. Z. Bloh,NO, NO2 and O3 J. Patzsch, A. Folli, D. MacPhee, J. Z. Bloh, NO, NO2 and O3
PCCP accepted (2017)dation activity (50%) PCCP, accepted (2017)dation activity (50%)
n NOn NO2
t P j tt Projectt Project