富炔高分子负载纳米钯催化剂复合材料的制备及其室温消氢性能研究

Hydrogen getters have been applied extensively in many areas of concern, such as in eliminating hydrogen isotopes leaked from gas storage system or produced by surrounding materials, which is benefit to guaranteeing environmental safety and preventing materials from hydrogen corrosion. The irreversible hydrogen getters at normal temperatures and pressures are more important, which are usually prepared by mixing the carbon-supported Pd catalyst with the solid –state alkynyl polymer materials. However, the hydrogen absorption efficiency of such hydrogen getters is very low because of the large difficulties or barriers for alkynes transferring to the surface of solid catalyst. In addition, the contact between the solid reactant and solid catalyst becomes more difficult when the getters are imbedded in other polymers required for many applications..This research aims to prepare novel hydrogen getters which can eliminate hydrogen at normal temperatures and pressures, based on the idea of preparing alkynyl-riched polymers and compositing them with Pd nanoparticles. The macromolecule plays a dual role in the hydrogenation reaction, the reactant as well as the scaffold to immobilize Pd nanoparticles. In this way, the “contact problem” between solid reactants and solid catalysts may be resolved. The alkynyl-riched polymer will be synthesized by employing polyvinyl alcohol and alkynyl compounds. Pd Nanoparticles can be encapsulated and stabilized by the alkynyl-riched polymer. On the basis of the above work, the relationship between the structure and the hydrogen elimination behaviors and mechanism of the Pd nanoparticles / alkynyl-riched polymer composites will be studied detailed. Ultimately, we hope to obtain optimal parameters to prepare some Pd nanoparticles / alkynyl-riched polymer composites with better hydrogen elimination performance at room temperature and normal pressures.

消氢材料在含氢同位素的环境安全、易发生氢化反应材料（如铀、钚等核材料及其废物）的安全贮存等方面有重要应用。其中，非能动室温不可逆消氢材料是该领域的研究热点。目前，常用含炔基的固态有机材料与活性炭等负载的钯催化剂机械混合后，作为室温不可逆消氢剂。然而，利用机械法混合的消氢剂在使用时存在固态有机反应物与催化剂难以充分接触、钯易团聚、与高分子二次复合困难等问题，从而严重影响其消氢效率及应用。本项目提出将富炔高分子与纳米钯催化剂有机复合的设计思路，以实现催化剂载体与含炔基反应物的一体化，可有效解决以上问题。拟以聚乙烯醇为基合成富炔高分子，然后与纳米钯前驱体混溶，通过还原法获得富炔聚乙烯酯（或醚）类高分子稳定的纳米钯，实现催化剂载体与反应物的二合一。研究富炔高分子负载纳米钯复合材料的结构与其室温消氢性能的关系，获得该新型消氢材料的制备技术，并进一步研究其与其它材料二次复合后的消氢性能与机理。

消氢材料在含氢同位素的环境安全、易发生氢化反应材料的安全贮存等方面具有重要应用。室温不可逆消氢材料是该领域的研究热点。本项目首先制备了不同结构的富炔高分子并通过化学还原法和冷冻干燥法制备了富炔高分子负载纳米钯催化剂胶体溶液、凝胶及其粉体，发现纳米钯粒子均匀分散在富炔高分子网络中。所设计的富炔高分子负载纳米钯复合材料液相消氢效率接近100%，但固相消氢效率较低（<10%）。接着，以富炔高分子作为吸氢反应物，商品化的Pd/C、溶胶-凝胶（sol-gel）法合成的钯纳米颗粒（PdNPs）等作为催化剂，通过物理混合、浸渍法、二次负载等手段将吸氢反应物与催化剂复合，形成吸氢复合材料，发现消氢效果仍不理想；最后，采用石墨烯、碳气凝胶、多孔碳等新型碳材料代替活性炭载体负载纳米钯或钯镍双金属催化剂，发现钯镍双金属催化剂具有优异的固态催化加氢性能；碳气凝胶吸氢材料不但吸氢量高且可成型，实现了成型与吸氢一体化的设计目标，为密闭系统的消氢、控氢提供了技术支撑。