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Increasing the Selectivity of DeN Increasing the Selectivity of DeN Increasing the Selectivity of DeN S i h E l i fT Suppressing the Evolution of Tox Suppressing the Evolution of Tox J. Patzsch, J. Z. Bloh| e‐mail: [email protected]| BMWi via AiF| Period J. Patzsch, J. Z. Bloh| e mail: [email protected]| BMWi via AiF| Period h l Photocatalysis Photocatalysis • Reduction of O 2 to superoxide 2 • Oxidation of water to ∙OH by V • Oxidation of water to OH by V O H O d OH idi • O 2 ∙‐ ,H 2 O 2 and ∙OH can oxidize 2 2 2 • Removal of NO 3 ‐ from the surf Removal of NO 3 from the surf • Adsorbed NO ‐ can be re‐reduc • Adsorbed NO 3 can be re‐reduc ‐ electrons electrons R d i i ii • Re‐reduction in competition w • Co‐Catalysts support the full o and suppress the back reaction and suppress the back reaction Influence of iron grafting Influence of iron grafting • Up to 120 % hig • Up to 120 % hig Optimum concentration for P25: Th l fN • The release of N 0 003 to 0 1 mol% iron h l 0.003 to 0.1 mol% iron • Higher toleranc 10 to 400 Fe 3+ /particle 10 to 400 Fe 3 /particle • Higher possible Higher possible Environmentally relevant mixture of NO NO and O Environmentally relevant mixture of NO, NO 2 and O 3 NO NO NO O NO NO 200 NO NO 2 NO x O 3 200 NO NO 200 200 150 150 150 ppb 150 pb] n / p n [pp 100 ation 100 ation 100 entra 100 entra once once Co Co 50 50 07 17 27 0 00 02 04 06 0 0,7 1,7 2,7 time [h] 0,0 0,2 0,4 0,6 ti time [h] ti U difi d P25 Unmodified P25: P25 grafted with ju • Low activity for NO x degradation (8%) • Degradation of N x Degradation of N • NO is mainly converted to NO 2 • High NO degrad NO is mainly converted to NO 2 • High NO x degrad • NO is increased by 40% • 40% decrease in • NO 2 is increased by 40%. • 40% decrease in Hi hli h Highligh Highligh 2017 2017 2017 Chemical Technology Chemical Technology NOx Photocatalysts and NOx Photocatalysts and NOx Photocatalysts and iB P d xic By‐Products xic By‐Products d: 01.06.2015‐31.08.2017 d: 01.06.2015 31.08.2017 1 2 Measurements 1 2 Measurements or H 2 O 2 by CB electrons 2 2 • Based on the ISO VB holes Based on the ISO VB holes standard 22197 1 O h i standard 22197‐1 NO x to the nitrate G fl f 3 L/ i x • Gas flow of 3 L/min ace by rain / ² ace by rain • UV light of 1 mW/cm² ced to NO by CB ced to NO 2 by CB • 50 % relative humidity 50 % relative humidity • 1 ppm NO or 1 ppm O ihO d i • 1 ppm NO or 1 ppm O 3 with O 2 reduction • Aeroxide P25 (Evonik) 2 • Aeroxide P25 (Evonik) xidation to nitrate n from nitrate n from nitrate 3 3 gher selectivity and 110 % activity by modification with Fe 3+ gher selectivity and 110 % activity by modification with Fe NO id ti ll dl d d l h ft l ti NO 2 is drastically delayed and only happens after long exposure times d h h h l df hl ce towards nitrate poisoning, the high selectivity is retained for a much longer time e nitrate accumulation on the surface e nitrate accumulation on the surface 4 5 Summary & Literature 4 5 Summary & Literature hl l d h l b O NO O • Highly selective and active photocatalyst by O 2 NO x O 3 grafting of low amounts of iron on the surface grafting of low amounts of iron on the surface • Long term stable materials against catalyst • Long term stable materials against catalyst poisoning of nitrate poisoning of nitrate Si ifi d d i f NO NO d • Significant degradation of NO, NO 2 and ozone 2 in environmentally relevant mixtures 08 10 12 14 16 • J Patzsch J Z Bloh Catal Today accepted 0,8 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, NO 2 and O 3 J. Patzsch, A. Folli, D. MacPhee, J. Z. Bloh, NO, NO 2 and O 3 PCCP accepted (2017) dation activity (50%) PCCP, accepted (2017) dation activity (50%) n NO n NO 2 tP j t t Project t Project
