Ning Xiang,Yaqin Hou,Xiaojin Han,Yulin Li,Yaoping Guo,Yongjin Liu,Zhanggen Huang
Room temperature HCHO catalytic oxidation over inert support loaded Pd catalysts remains a significant challenge. Herein, a series of alkali Na (1–4 wt.%) modified 1Pd/SBA-15 catalysts were prepared by a co-impregnation method and used for HCHO catalytic oxidation at room temperature. Results showed that alkali Na significantly improved the HCHO oxidation performance of 1Pd/SBA-15 and the optimal Na loading was 2 wt.%. BET, XRD, STEM, XPS, H 2 -TPR, O 2 -TPD and in situ DRIFTS were performed to reveal the promotion role of alkali Na. As a consequence, alkali Na addition could stabilize well dispersed Pd particles which then facilitated the O 2 activation and accelerated the decomposition of formate intermediates species, thus a superior HCHO catalytic oxidation performance was obtained. This study first clearly illustrated the promotion mechanism of alkali Na without the implication of active support and provides an efficient and facile way to achieve high dispersion of Pd particles on inert support and tremendously expands the selected range of supports for room temperature HCHO catalytic oxidation. Graphical Alkali promoted : A series of Na alkali-promoted 1Pd/SBA15 catalysts were prepared by a co-impregnation method and tested for HCHO catalytic oxidation at room temperature. Addition of alkali Na stabilized well-dispersed Pd particles which facilitated O 2 activation and accelerated formate species decomposition rate, leading to superior HCHO catalytic oxidation performance of 2Na-1Pd/SBA-15.
Solid phosphoric acid (SPA) catalysts with different carriers were prepared and used for catalytic fast pyrolysis of poplar wood to produce levoglucosenone (LGO), a valuable anhydrosugar derivative that can be used in various organic synthesis applications. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to evaluate the catalytic capabilities of these catalysts under different reaction conditions. The results indicated that SPA catalyst prepared with the SBA-15 carrier exhibited the best catalytic capability for selectively producing LGO. Both the catalytic pyrolysis temperature and catalyst-to-biomass ratio affected the pyrolytic products greatly. The maximal LGO yield reached as high as 8.2 wt% from poplar wood, obtained at the pyrolysis temperature of 300 °C and the catalyst-to-biomass ratio of 1. The by-products during the catalytic pyrolysis process were mainly acetic acid (AA) and furfural (FF). In addition, the SPA catalyst possessed better catalytic capability than the liquid phosphoric acid (H 3 PO 4 ) catalyst to produce LGO.
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