用于常温氢氧复合的新型Pt/疏水改性陶瓷催化剂

Novel Pt/hydrophobic Modified Ceramic Catalyst Used in Room-temperature Hydrogen-oxygen Recombination Reaction

常温氢氧复合反应由于安全性高且能耗低,在核工业除氚、消氢等领域有重要应用,其得以实现的关键为制得性能优异的疏水催化剂。为获得稳定性优且兼具高催化活性的疏水催化剂,本研究制备了新型Pt/疏水改性陶瓷催化剂。陶瓷载体通过构筑CeO2表面粗糙结构,结合涂覆低表面能十三氟辛基三甲氧基硅烷(PFOTMS)进行疏水改性,而后经浸渍-气相还原制得疏水催化剂。结果表明,与常规仅涂覆低表面能材料对陶瓷载体进行疏水改性相比,新型疏水结构的构筑不仅可使疏水催化剂获得更优的疏水性,还可进一步提升催化剂的催化活性及稳定性。制得的新型Pt/疏水改性陶瓷催化剂在480 min反应时长内,氢氧复合效率可维持在99.5%。

Hydrogen-oxygen recombination reaction at the room-temperature has been widely used in the nuclear industry to avoid the leakage of tritium and the risk of hydrogen explosion for its high safety and low energy consumption.The key to realize the recombination reaction is to prepare the hydrophobic catalyst with excellent properties.However,current catalyst exhibits low heat tolerance,poor heat conductivity and short life.Thus,there is still a need to produce more stable and active hydrophobic catalysts,while the ceramic carrier with hydrophobic structure is expected to cover this requirement.In the reported studies,the hydrophobicity of ceramic support was usually obtained by coating with low surface energy materials,while this kind of hydrophobic ceramic carrier is no longer advantageous with the development of new hydrophobic ceramic materials.In this study,the novel hydrophobic modified ceramic was adopted as carrier to fabricate the new type of Pt/hydrophobic modified ceramic catalyst.The hydrophobic ceramic carrier was obtained by constructing the rough surface structure of CeO2 combined with the low surface energy perfluorosilane(PFOTMS)coating.Then the catalyst was prepared through impregnation method using Pt-precursor solution and H2 reduction.Compared with conventional Pt/hydrophobic ceramic catalyst which the ceramic carrier was only covered by the hydrophobic coating,the new Pt/hydrophobic modified ceramic catalyst not only makes the catalyst more hydrophobic,but also helps the prepared catalyst to obtain better combination efficiency and catalytic stability.The rough surface structure of CeO2 was proved with the high specific surface area,which could provide more sites for PFOTMS adhering to the carrier and achieving protection.Hence the hydrophobicity of the catalyst is improved,and the hydrophobic structure is almost not destroyed during the reaction process,which improves the stability of the catalyst.The rough surface structure of CeO2 could also significantly increase the specific surface area of ceramic carrier,which could help the Pt particle more uniformly deposit on the carrier resulting in increased Pt0 content and reduced Pt particle size,thereby improving catalytic activity.Meanwhile,the novel hydrophobic structure could also provide more sites for Pt particle depositing on the surface of the carrier,it could participate in the reaction preferentially than the inner Pt particle for the long process of reaction gas diffuse into the catalyst,which could also improve the catalytic activity in theory.The novel Pt/hydrophobic modified ceramic catalyst could maintain the recombination efficiency of 99.5%in the reaction time of 480 min,exhibiting improved activity and stability,which would have a good application prospect in the room-temperature hydrogen-oxygen recombination reaction.