The conversion of CO 2 into ethanol with value-added still exists challenge, especially the CO 2 hydrogenation over Co-based catalysts is still C1 product dominated by CH 4 . Here, we report a xNa-CoMnO catalyst to promoting ethanol synthesis from CO 2 hydrogenation. The experimental results indicated that there was almost no adsorption and conversion of CO 2 on pure Co 0 , and the CO 2 hydrogenation production of the CoMnO catalyst prepared by adding Mn was mainly CH 4 . The loading of Na not only increased the concentration of oxygen defects on the CoMnO catalyst, but also improved the strength of the Co-O in the CoMnO catalyst, which was able to adsorb effectively the undissociated *CO in the reaction process, and promote the C-C coupling between the *CO and the generated *CH x , promoted the synthesis of ethanol. Under optimized reaction conditions (240 °C, 3.0 MPa, GHSV = 1200 mL/g/h), the 2Na-CoMnO catalyst showed ethanol selectivity of 18.89 % and space-time yield of ethanol of 1.27 mmol/g/h, which exceeded most of the reported results. More importantly, beyond delivering an excellent-performance catalytic system, this study also provides fundamental insights for the rational design of Co-based catalysts for selective CO 2 -to-ethanol conversion.
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.