Как условия синтеза влияют на электронное состояние Pt?
В какой реакции планируется использовать катализаторы и какое электронное состояние платины будет желательным?
Как условия синтеза влияют на электронное состояние Pt?
Pt precursor solution composition and reducing agents strongly influence the oxidation state and also the particle size of Pt. Pt (IV) nitrate solution modified with TMA (tetramethylammonium hydroxide) due to small particle size of Pt(OH)x oligomers present in the solution, has strong interaction with the Sibunit support and facilitates the reduction of Pt4+ to Pt2+ after deposition (according to XPS). So before reduction just after precursor deposition the Pt4+/Pt2+ ratio depends on 1) support pretreatment, 2) solution composition (the most important).
В какой реакции планируется использовать катализаторы и какое электронное состояние платины будет желательным?
These catalysts can be used for different types of reactions but our goal is to use them for selective hydrogenation of organic compounds. For that reason, we used reduction procedure (NaBH4 and H2) to obtain a metallic Pt. (According to XPS we Pt (met) dominates for both H2 and NaBH4 (with small portion of ionic states). Choosing reduction conditions it was important do not cause the sintering. In that case NaBH4 gives good results with a narrow particle size distribution with a mean size of 2.1 nm and 2.5 nm, while H2 causes agglomeration and sintering of Pt particles which is not desirable.
The accuracy of determining the surface area is about 2%.
Локтева Екатерина Сергеевна
3 лет назад
Правильно ли я поняла, что каталитических испытаний пока не было? Есть ли у вас соображения, для каких реакций или условий хороши будут более крупные частицы, а для каких более мелкие и однородные?
Small well dispersed Pt particles are good for hydrogenation.
For the oxidation commonly we see direct size effect for platinum catalysts. The best range of particle size is about 6 — 8 nm, further increase of size doesn’t make sense due to drop of working surface area.
Смирнов Андрей Валентинович
3 лет назад
Есть ли данные, какой размер частиц платины получился бы на Сибуните без предварительной предобработки?
Mean particle size of Pt obtained without pretreatment of sibunit is 2.1 nm. It is also illustrated by second histogram containing TMA and NaBH4 in poster, please review it.
Как условия синтеза влияют на электронное состояние Pt?
В какой реакции планируется использовать катализаторы и какое электронное состояние платины будет желательным?
Как условия синтеза влияют на электронное состояние Pt?
Pt precursor solution composition and reducing agents strongly influence the oxidation state and also the particle size of Pt. Pt (IV) nitrate solution modified with TMA (tetramethylammonium hydroxide) due to small particle size of Pt(OH)x oligomers present in the solution, has strong interaction with the Sibunit support and facilitates the reduction of Pt4+ to Pt2+ after deposition (according to XPS). So before reduction just after precursor deposition the Pt4+/Pt2+ ratio depends on 1) support pretreatment, 2) solution composition (the most important).
В какой реакции планируется использовать катализаторы и какое электронное состояние платины будет желательным?
These catalysts can be used for different types of reactions but our goal is to use them for selective hydrogenation of organic compounds. For that reason, we used reduction procedure (NaBH4 and H2) to obtain a metallic Pt. (According to XPS we Pt (met) dominates for both H2 and NaBH4 (with small portion of ionic states). Choosing reduction conditions it was important do not cause the sintering. In that case NaBH4 gives good results with a narrow particle size distribution with a mean size of 2.1 nm and 2.5 nm, while H2 causes agglomeration and sintering of Pt particles which is not desirable.
Какова точность определения площади поверхности?
The accuracy of determining the surface area is about 2%.
Правильно ли я поняла, что каталитических испытаний пока не было? Есть ли у вас соображения, для каких реакций или условий хороши будут более крупные частицы, а для каких более мелкие и однородные?
Yes, we didn’t do catalytic tests yet.
Small well dispersed Pt particles are good for hydrogenation.
For the oxidation commonly we see direct size effect for platinum catalysts. The best range of particle size is about 6 — 8 nm, further increase of size doesn’t make sense due to drop of working surface area.
Есть ли данные, какой размер частиц платины получился бы на Сибуните без предварительной предобработки?
Mean particle size of Pt obtained without pretreatment of sibunit is 2.1 nm. It is also illustrated by second histogram containing TMA and NaBH4 in poster, please review it.