Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still car...Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.展开更多
由单一还原剂 NaH_2PO_2或 NaH_2PO_3与 KBH_4的复合还原剂分别在类镍溶液中获得 Ni-Fe-P 以及 Ni-Fe-P-B 合金膜,研究了这些新型合金膜的磁性。结果发现,铁磁性元素 Fe 含量增加导致原子平均磁矩及饱和磁化强度 Ms 增大;结构为非晶态...由单一还原剂 NaH_2PO_2或 NaH_2PO_3与 KBH_4的复合还原剂分别在类镍溶液中获得 Ni-Fe-P 以及 Ni-Fe-P-B 合金膜,研究了这些新型合金膜的磁性。结果发现,铁磁性元素 Fe 含量增加导致原子平均磁矩及饱和磁化强度 Ms 增大;结构为非晶态的合金膜具有较优的矫顽力 Hc 值;合金膜磁滞回线出现较低的矩形比说明化学镀制备态样品不够均匀;热处理温度高于400℃后,合金膜的饱和磁化强度连续减小,矫顽力急剧增大;同时,镀层的均匀性明显得到改善。展开更多
The reduction behavior of Y-Al2O3 supported iron and platinum-iron catalysts was studied by TPR combined in situ 57Fe MBS. The results indicated that Fe3+ is highly dis-persed on the Y-Al2O3 surface for all the sample...The reduction behavior of Y-Al2O3 supported iron and platinum-iron catalysts was studied by TPR combined in situ 57Fe MBS. The results indicated that Fe3+ is highly dis-persed on the Y-Al2O3 surface for all the samples containing iron before the reduction. No Fe was found in the reduction process. The Fe3+ was reduced to Fe2+ in tetrahedral vacancy first in Pt-Fe/Y-Al2O3 sample in TPR process. The TPR processes of all supported iron samples are very different from those of α-Fe2O3.展开更多
基金supported by the National Natural Science Foundation of China (U1303291)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R46)
文摘Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.
文摘由单一还原剂 NaH_2PO_2或 NaH_2PO_3与 KBH_4的复合还原剂分别在类镍溶液中获得 Ni-Fe-P 以及 Ni-Fe-P-B 合金膜,研究了这些新型合金膜的磁性。结果发现,铁磁性元素 Fe 含量增加导致原子平均磁矩及饱和磁化强度 Ms 增大;结构为非晶态的合金膜具有较优的矫顽力 Hc 值;合金膜磁滞回线出现较低的矩形比说明化学镀制备态样品不够均匀;热处理温度高于400℃后,合金膜的饱和磁化强度连续减小,矫顽力急剧增大;同时,镀层的均匀性明显得到改善。
文摘The reduction behavior of Y-Al2O3 supported iron and platinum-iron catalysts was studied by TPR combined in situ 57Fe MBS. The results indicated that Fe3+ is highly dis-persed on the Y-Al2O3 surface for all the samples containing iron before the reduction. No Fe was found in the reduction process. The Fe3+ was reduced to Fe2+ in tetrahedral vacancy first in Pt-Fe/Y-Al2O3 sample in TPR process. The TPR processes of all supported iron samples are very different from those of α-Fe2O3.
