A composite of LiBH4-Mg2NiH4 doped with 10wt% CEH2.29 was prepared by ball milling followed by dynamic interspace vac- uum treatment at 573 K. The introduction of CEH2.29 caused a transformation in the morphology of M...A composite of LiBH4-Mg2NiH4 doped with 10wt% CEH2.29 was prepared by ball milling followed by dynamic interspace vac- uum treatment at 573 K. The introduction of CEH2.29 caused a transformation in the morphology of Mg from complex spongy and lamellar to uniformly spongy, resulting in refined particle size and abundant H diffusion pathways. This LiBH4-Mg2NiH4 ＋ 10wt% CEH2.29 composite exhibited excellent hydrogen storage properties. The starting temperature of rapid H absorption decreased to 375 K in the doped composite from 452 K for the unmodified material, and the onset decomposition temperature of its hydride was reduced from 536 K to 517 K. In addi- tion, the time required for a hydrogen release of 1.5wt% （at 598 K） was 87 s less than that of the un-doped composite.展开更多
Nickel-CeO_(2)-based materials are commonly used for the thermal catalytic hydrogenation of CO_(2).However,high Ni loadings and low CO selectivity restrict their use in the reverse water–gas shift(RWGS)reaction.Herei...Nickel-CeO_(2)-based materials are commonly used for the thermal catalytic hydrogenation of CO_(2).However,high Ni loadings and low CO selectivity restrict their use in the reverse water–gas shift(RWGS)reaction.Herein,we demonstrate a highly active,robust,and low-Ni-doped(1.1 wt.%)CeO_(2) catalyst(1.0-Ni-CeO_(2)).The Ni-based-mass-specific CO formation rate reaches up to 1,542 mmol·gNi^(−1)·h^(−1) with 100%CO selectivity at 300°C for 100 h,among the best values reported in the literature.Density functional theory(DFT)and diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)results reveal that the enhanced catalytic activity is attributed to the abundant Ce–H species,while the high selectivity results from low CO affinity.More importantly,a new reaction mechanism is proposed,which involves the reduction of bicarbonate to generate formate intermediate and CO by the H−released from Ce–H species.The new findings in this work will benefit the design of economic,efficient,and robust catalysts for low-temperature RWGS reactions.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 50971112)the Natural Science Foundation of Hebei Province (No. E2010001170)the Scientific Research Projects in Colleges and Universities in Hebei Province, China (No. ZD2014004)
文摘A composite of LiBH4-Mg2NiH4 doped with 10wt% CEH2.29 was prepared by ball milling followed by dynamic interspace vac- uum treatment at 573 K. The introduction of CEH2.29 caused a transformation in the morphology of Mg from complex spongy and lamellar to uniformly spongy, resulting in refined particle size and abundant H diffusion pathways. This LiBH4-Mg2NiH4 ＋ 10wt% CEH2.29 composite exhibited excellent hydrogen storage properties. The starting temperature of rapid H absorption decreased to 375 K in the doped composite from 452 K for the unmodified material, and the onset decomposition temperature of its hydride was reduced from 536 K to 517 K. In addi- tion, the time required for a hydrogen release of 1.5wt% （at 598 K） was 87 s less than that of the un-doped composite.
基金the Science and Technology Project of Shenzhen(No.JCYJ20190806155814624)the National Natural Science Foundation of China(No.22002120)the Fundamental Research Funds for the Central Universities(No.3102017jc01001).
文摘Nickel-CeO_(2)-based materials are commonly used for the thermal catalytic hydrogenation of CO_(2).However,high Ni loadings and low CO selectivity restrict their use in the reverse water–gas shift(RWGS)reaction.Herein,we demonstrate a highly active,robust,and low-Ni-doped(1.1 wt.%)CeO_(2) catalyst(1.0-Ni-CeO_(2)).The Ni-based-mass-specific CO formation rate reaches up to 1,542 mmol·gNi^(−1)·h^(−1) with 100%CO selectivity at 300°C for 100 h,among the best values reported in the literature.Density functional theory(DFT)and diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)results reveal that the enhanced catalytic activity is attributed to the abundant Ce–H species,while the high selectivity results from low CO affinity.More importantly,a new reaction mechanism is proposed,which involves the reduction of bicarbonate to generate formate intermediate and CO by the H−released from Ce–H species.The new findings in this work will benefit the design of economic,efficient,and robust catalysts for low-temperature RWGS reactions.
