| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 66033 | Journal of Molecular Catalysis A: Chemical | 2012 | 7 Pages |
Palladium catalysts supported on HZSM-5 (Pd/HZSM-5-X (X = 15, 30, 75, 100, and 150)) were prepared with a variation of Si/Al molar ratio (X), and they were applied to the direct synthesis of hydrogen peroxide from hydrogen and oxygen. Conversion of hydrogen over Pd/HZSM-5-X catalysts showed no great difference, while selectivity for hydrogen peroxide over the catalysts exhibited a volcano-shaped curve with respect to Si/Al molar ratio. As a consequence, yield for hydrogen peroxide over the catalysts showed a volcano-shaped curve with respect to Si/Al molar ratio. Yield for hydrogen peroxide over Pd/HZSM-5-X catalysts was closely related to the Brönsted acidity/Lewis acidity (B/L) ratio of the catalysts. Yield for hydrogen peroxide increased with increasing B/L ratio of Pd/HZSM-5-X catalysts. This indicates that Brönsted acid sites of Pd/HZSM-5-X catalysts played an important role for enhancing the catalytic performance in the direct synthesis of hydrogen peroxide. Furthermore, yield for hydrogen peroxide increased with increasing Brönsted acidity of Pd/HZSM-5-X catalysts. Among the catalysts tested, Pd/HZSM-5-30 catalyst with the largest Brönsted acidity showed the highest yield for hydrogen peroxide. Therefore, it is concluded that Brönsted acidity of Pd/HZSM-5-X catalysts served as an important factor determining the catalytic performance in the direct synthesis of hydrogen peroxide.
Graphical abstractIn the direct synthesis of hydrogen peroxide from hydrogen and oxygen over Pd/HZSM-5 catalysts, yield for hydrogen peroxide increased with increasing B/L ratio of the catalysts.Figure optionsDownload full-size imageDownload high-quality image (81 K)Download as PowerPoint slideHighlights► Direct synthesis of hydrogen peroxide from hydrogen and oxygen was conducted. ► Pd/HZSM-5-X catalysts with different Si/Al molar ratio (X) were used. ► Yield for hydrogen peroxide increased with increasing B/L ratio of the catalyst. ► Yield for hydrogen peroxide increased with increasing Brönsted acidity of the catalyst.
