The development of highly efficient electrocatalysts with low cost for oxygen reduction reaction (ORR) is urgently required for metal-air batteries and fuel cells. In this work, Fe Co/MIL-101(Cr) with various molar ratios of Fe/Co as hybrid catalysts was prepared by a facile and mild impregnation method. MIL-101(Cr) increased the specific surface areas of the hybrid catalysts, thus improving the dispersion of Fe and Co species at their surfaces. The effects of Fe and Co species on ORR activity of the hybrid catalysts were investigated. It is found that the synergistic effects between the well-dispersed Fe and Co species contribute mainly to ORR activity. More specifically, Fe species exert a partial-charge-transfer-activation effect on Co ones, which reduces the charge transfer resistance and thus improves the catalytic activity . As a result, Fe Co/MIL-101(Cr) showed the excellent ORR activity, in which Co 50 Fe 50 /MIL-101(Cr) exhibited the superior ORR activity to the other prepared hybrid catalysts.
Chenxi Lu,Yuanzhuo Zhou,Liangzhi Li,Hongwei Chen,Lishi Yan
Catalytic production of 5-hydroxymethylfurfural (5-HMF) from glucose is a promising routine for generation of varied value-added chemicals. Herein, Mixed-Metal metal–organic frameworks (MOFs)–Fe/MIL-101(Cr) and MIL-101(Cr, Fe) obtained from post-synthesis modification and one-pot synthesis approach respectively were applied for catalytic converting glucose to 5-HMF. The synthesized Mixed-Metal MOFs were characterized by PXRD, SEM, N 2 adsorption–desorption analysis, TGA, XPS and NH 3 -TPD. Cr-and Fe-containing Mixed-Metal MOFs Fe/MIL-101(Cr) and MIL-101(Cr, Fe) presented synergistic effect with enhanced catalytic ability for glucose transformation to 5-HMF compared with typical single-metal MOFs and sulfonic acid-functionalized MOFs. Moreover, these two Mixed-Metal MOFs also presented better thermal stability than single-metal MOFs like MIL-101(Cr). Fe/MIL-101(Cr) was found to possess higher catalytic performance than MIL-101(Cr, Fe). 55.8 % 5-HMF yield was obtained with Fe/MIL-101(Cr) at 170 °C for 2 h in DMSO/water system. In addition, Fe/MIL-101(Cr) demonstrated desired recyclability for five times without incredible loss in its activity. This study provides a Mixed-Metal strategy on MOFs for improving catalytic efficiency of glucose conversion to 5-HMF.
危险品化学品经营许可证（带存储）