Effect of potassium addition on bimetallic PtSn/θ-Al2O3 catalyst for dehydrogenation of propane to propylene

Mi Hyun Lee, Bhari Mallanna Nagaraja, Prakash Natarajan, Ngoc Thanh Truong, Kwan Young Lee, Sungho Yoon, Kwang Deog Jung

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

PtSn/θ-Al2O3 catalysts with different amounts of K (0.14, 0.22, 0.49, 0.72, and 0.96 wt%) are prepared to investigate the K effects on the PtSn catalyst in propane dehydrogenation (PDH). KPtSn catalyst with 0.xx wt% K, 0.5 wt% Pt and 0.75 wt% Sn is designated as xx-KPtSn. PDH was performed at 873 K and a gas hourly space velocity (GHSV) of 53,000 mL/gcat h. The temperature-programmed desorption (NH3-TPD), temperature-programmed reduction (TPR) and CO chemisorption of the KPtSn catalysts with K added revealed the potassium addition blocked the acid sites, promoted the reduction of Sn oxide and decreased the Pt dispersion. The formations of cracking products and higher hydrocarbons on acid sites were suppressed by the K effect of blocking the acid sites. In contrast, K addition at more than 0.72 wt% rather increased cracking products and the amount of coke, resulting in the severe deactivation of catalysts. The high cracking products on the KPtSn catalysts with the high amount of K should not be related to the acid sites, because the acid sites were monotonously decreased with an increase in the amount of K. Instead, the potassium affected the characteristics of PtSn. The interaction between Pt and Sn could be weakened by enriching the reduced Sn, because the K component promoted the reduction of Sn oxide in the TPR experiments. Therefore, the 14-KPtSn catalyst with the low amount of K exhibits the highest stability and selectivity among the prepared KPtSn catalysts due to the compromise of the advantageous (blocking the acid sites) and bad (weakening the interaction between Pt and Sn) effects of the K addition in PDH.

Original languageEnglish
Pages (from-to)123-140
Number of pages18
JournalResearch on Chemical Intermediates
Volume42
Issue number1
DOIs
Publication statusPublished - 2016 Jan 1

Fingerprint

Propane
Dehydrogenation
Potassium
Catalysts
Acids
Temperature programmed desorption
Oxides
propylene
Catalyst selectivity
Carbon Monoxide
Chemisorption
Hydrocarbons
Coke
Gases
Temperature

Keywords

  • K(PtSn)/θ-AlO catalyst
  • Propane dehydrogenation
  • Propylene
  • PtSn alloy formation

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Effect of potassium addition on bimetallic PtSn/θ-Al2O3 catalyst for dehydrogenation of propane to propylene. / Lee, Mi Hyun; Nagaraja, Bhari Mallanna; Natarajan, Prakash; Truong, Ngoc Thanh; Lee, Kwan Young; Yoon, Sungho; Jung, Kwang Deog.

In: Research on Chemical Intermediates, Vol. 42, No. 1, 01.01.2016, p. 123-140.

Research output: Contribution to journalArticle

Lee, Mi Hyun ; Nagaraja, Bhari Mallanna ; Natarajan, Prakash ; Truong, Ngoc Thanh ; Lee, Kwan Young ; Yoon, Sungho ; Jung, Kwang Deog. / Effect of potassium addition on bimetallic PtSn/θ-Al2O3 catalyst for dehydrogenation of propane to propylene. In: Research on Chemical Intermediates. 2016 ; Vol. 42, No. 1. pp. 123-140.
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abstract = "PtSn/θ-Al2O3 catalysts with different amounts of K (0.14, 0.22, 0.49, 0.72, and 0.96 wt{\%}) are prepared to investigate the K effects on the PtSn catalyst in propane dehydrogenation (PDH). KPtSn catalyst with 0.xx wt{\%} K, 0.5 wt{\%} Pt and 0.75 wt{\%} Sn is designated as xx-KPtSn. PDH was performed at 873 K and a gas hourly space velocity (GHSV) of 53,000 mL/gcat h. The temperature-programmed desorption (NH3-TPD), temperature-programmed reduction (TPR) and CO chemisorption of the KPtSn catalysts with K added revealed the potassium addition blocked the acid sites, promoted the reduction of Sn oxide and decreased the Pt dispersion. The formations of cracking products and higher hydrocarbons on acid sites were suppressed by the K effect of blocking the acid sites. In contrast, K addition at more than 0.72 wt{\%} rather increased cracking products and the amount of coke, resulting in the severe deactivation of catalysts. The high cracking products on the KPtSn catalysts with the high amount of K should not be related to the acid sites, because the acid sites were monotonously decreased with an increase in the amount of K. Instead, the potassium affected the characteristics of PtSn. The interaction between Pt and Sn could be weakened by enriching the reduced Sn, because the K component promoted the reduction of Sn oxide in the TPR experiments. Therefore, the 14-KPtSn catalyst with the low amount of K exhibits the highest stability and selectivity among the prepared KPtSn catalysts due to the compromise of the advantageous (blocking the acid sites) and bad (weakening the interaction between Pt and Sn) effects of the K addition in PDH.",
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T1 - Effect of potassium addition on bimetallic PtSn/θ-Al2O3 catalyst for dehydrogenation of propane to propylene

AU - Lee, Mi Hyun

AU - Nagaraja, Bhari Mallanna

AU - Natarajan, Prakash

AU - Truong, Ngoc Thanh

AU - Lee, Kwan Young

AU - Yoon, Sungho

AU - Jung, Kwang Deog

PY - 2016/1/1

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N2 - PtSn/θ-Al2O3 catalysts with different amounts of K (0.14, 0.22, 0.49, 0.72, and 0.96 wt%) are prepared to investigate the K effects on the PtSn catalyst in propane dehydrogenation (PDH). KPtSn catalyst with 0.xx wt% K, 0.5 wt% Pt and 0.75 wt% Sn is designated as xx-KPtSn. PDH was performed at 873 K and a gas hourly space velocity (GHSV) of 53,000 mL/gcat h. The temperature-programmed desorption (NH3-TPD), temperature-programmed reduction (TPR) and CO chemisorption of the KPtSn catalysts with K added revealed the potassium addition blocked the acid sites, promoted the reduction of Sn oxide and decreased the Pt dispersion. The formations of cracking products and higher hydrocarbons on acid sites were suppressed by the K effect of blocking the acid sites. In contrast, K addition at more than 0.72 wt% rather increased cracking products and the amount of coke, resulting in the severe deactivation of catalysts. The high cracking products on the KPtSn catalysts with the high amount of K should not be related to the acid sites, because the acid sites were monotonously decreased with an increase in the amount of K. Instead, the potassium affected the characteristics of PtSn. The interaction between Pt and Sn could be weakened by enriching the reduced Sn, because the K component promoted the reduction of Sn oxide in the TPR experiments. Therefore, the 14-KPtSn catalyst with the low amount of K exhibits the highest stability and selectivity among the prepared KPtSn catalysts due to the compromise of the advantageous (blocking the acid sites) and bad (weakening the interaction between Pt and Sn) effects of the K addition in PDH.

AB - PtSn/θ-Al2O3 catalysts with different amounts of K (0.14, 0.22, 0.49, 0.72, and 0.96 wt%) are prepared to investigate the K effects on the PtSn catalyst in propane dehydrogenation (PDH). KPtSn catalyst with 0.xx wt% K, 0.5 wt% Pt and 0.75 wt% Sn is designated as xx-KPtSn. PDH was performed at 873 K and a gas hourly space velocity (GHSV) of 53,000 mL/gcat h. The temperature-programmed desorption (NH3-TPD), temperature-programmed reduction (TPR) and CO chemisorption of the KPtSn catalysts with K added revealed the potassium addition blocked the acid sites, promoted the reduction of Sn oxide and decreased the Pt dispersion. The formations of cracking products and higher hydrocarbons on acid sites were suppressed by the K effect of blocking the acid sites. In contrast, K addition at more than 0.72 wt% rather increased cracking products and the amount of coke, resulting in the severe deactivation of catalysts. The high cracking products on the KPtSn catalysts with the high amount of K should not be related to the acid sites, because the acid sites were monotonously decreased with an increase in the amount of K. Instead, the potassium affected the characteristics of PtSn. The interaction between Pt and Sn could be weakened by enriching the reduced Sn, because the K component promoted the reduction of Sn oxide in the TPR experiments. Therefore, the 14-KPtSn catalyst with the low amount of K exhibits the highest stability and selectivity among the prepared KPtSn catalysts due to the compromise of the advantageous (blocking the acid sites) and bad (weakening the interaction between Pt and Sn) effects of the K addition in PDH.

KW - K(PtSn)/θ-AlO catalyst

KW - Propane dehydrogenation

KW - Propylene

KW - PtSn alloy formation

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