摘要/Abstract

氢气作为21世纪最具发展前景的清洁能源, 一直备受关注. 寻找安全高效的储氢材料以转型到氢能社会是当前面临的最大挑战之一. 水合肼(N₂H₄•H₂O)具有高含氢量(w=8.0%), 完全分解产氢副产物仅为氮气和水, 被视为一种极具应用潜力的液相化学储氢材料. 开发高效、高选择性的催化剂以催化水合肼完全分解, 是研究水合肼分解产氢的关键. 本综述总结了水合肼分解产氢催化剂的设计、合成及其催化性能. 简要分析了肼分解的机理. 此外, 讨论了提高水合肼分解产氢催化剂的选择性和活性的策略, 比如添加强碱助剂/碱性载体、形成合金、降低金属催化剂的结晶度、减小粒子尺寸、以及增强金属与载体相互作用. 本研究进展可以为设计合成具有更高活性的氮基氢化物产氢催化剂提供指导和思路.
关键词: 化学储氢材料, 水合肼, 产氢, 催化剂
Hydrogen with remarkable energy density has attracted much attention as the green, sustainable chemical energy carrier and a substitute for traditional fossil fuels. The discovery of safe and efficient hydrogen storage materials for the transition to a hydrogen energy society is one of the biggest challenges for hydrogen energy applications today. Hydrous hydrazine (N₂H₄•H₂O), with its high hydrogen content (w=8.0%) and the advantage of CO-free hydrogen production, has significant advantages in hydrogen storage and release and is considered as a promising liquid-phase chemical hydrogen storage material. The development of efficient and highly selective catalysts is the key to release hydrogen from the decomposition of hydrous hydrazine. In the past decade, a lot of catalysts have been developed to improve the kinetic properties for hydrogen generation. In this review, we focus on the recent progress on catalyst design, synthesis and catalytic performance of the catalyst in hydrogen production from the selective decomposition of hydrous hydrazine. Ir, Rh and Ni monometallic catalysts were found to be very active toward the dehydrogenation of hydrazine. Among all the catalysts investigated, supported Pt-Ni, Rh-Ni and Pt-Co catalysts showed the highest activity. The mechanism of hydrazine decomposition was briefly analyzed. The cleavage of the N―H bond of N₂H₄ will facilitate the formation of H₂ and N₂, while N―N bond cleavage will result in the formation of NH₃ and N₂. In addition, we reviewed and discussed the strategies for promoting H₂ selectivity and activity of catalysts, such as the addition of strong base and/or alkaline carrier, formation of metal alloys, reduction of metal crystallinity and particle size, as well as the enhancement of the interaction between metal and support. The progress of this research may provide guidance for obtaining more active catalysts toward hydrogen production from nitrogen-based hydrides.
Key words: chemical hydrogen storage material, hydrazine hydrate, hydrogen production, catalyst


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