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题名	新型钼系复合析氢电催化剂的制备及性能研究
作者	崔伟
学位类别	硕士
答辩日期	2015-04
授予单位	中国科学院研究生院
授予地点	中国科学院长春应用化学研究所
导师	孙旭平
关键词	析氢反应 电化学 钼系化合物 海藻酸钠 复合催化剂
中文摘要	氢能作为一种公认的高效、清洁、零碳的二次能源, 有望代替传统的化石能源。在众多制氢技术当中，电解水制氢具有操作简单和产品纯度高等优点，受到了高度关注。克服在电极产生的高析氢过电位以降低能耗，开发高活性、高稳定性的析氢电催化剂具有重要意义。目前，铂基材料是最有效的析氢阴极催化剂，但由于铂在地球上储量少，大大制约了其大规模应用。近年来，低成本的过渡金属钼及其化合物展现出了较高的电催化析氢性能和稳定性，有望代替铂基电催化剂。本论文围绕钼系复合材料的制备及其电催化性能开展了一系列研究工作，主要的研究内容如下： 1. 采用常见的镍盐、钼酸盐、硫脲为原料，通过简单的一步水热法，制备了硫化镍掺杂的二硫化钼微球(NMSHMs)。这种复合材料在酸性环境中的电催化活性明显优于单独的硫化镍(NixSy)、二硫化钼(MoS2)及其物理混合物(mNM)。此外，通过控制镍盐的用量探索了镍的含量对二硫化钼微球催化性能的影响。 2. 采用在自然界广泛存在的生物大分子海藻酸钠作为碳源，钼酸铵作为钼源，采用高温煅烧法制备出碳化钼纳米颗粒修饰的石墨化碳片(Mo2C/GCSs)。碳化钼纳米颗粒尺寸在5-23 nm 之间，在碳片上分散性良好。该复合材料在酸性电解质中获得了较好的电催化析氢活性和稳定性，产氢效率接近100%。其中，由于碳化钼与碳之间具有牢固的键合作用，能有效加快电子转移速率，并能提高结强度。此外，碳片支持的纳米结构抑制了碳化钼颗粒的团聚，暴露更多的活性位点，从而获得优异的电催化性能。 3. 我们采用较绿色安全的内氧化还原策略，在上述体系中引入磷酸二氢钠作为磷源，在相同煅烧条件下制备了磷化钼纳米片与碳片的复合材料(MoP/CF)。与体相磷化钼(bulk MoP)相比，该材料在酸性及中性体系中展示了更优秀的电催化产氢性能。为证明在内氧化还原策略的普适性和碳的还原作用，进一步采用多壁碳纳米管作为碳源，在同样煅烧条件下得到了磷化钼纳米颗粒与碳管的复合材料(MoP/CNT)，该材料同样在酸性及中性体系中获得较好的电催化析氢性能。
英文摘要	Hydrogen, an efficient, clean, and carbon-free fuel, is being considered as a replacement for today's fossil fuels. Electrolysis of water is a simple way to produce hydrogen of high purity and has thus attracted considerable attention. In order to improve the reaction rate and lower the overpotential, an efficient and stable hydrogen evolution reaction (HER) electrocatalyst is usually required. Pt-based materials are the most efficient HER electrocatalysts, however, they are not sustainable catalysts for large-scale applications due to their scarcity on earth. Recently, it was found that molybdenum (Mo) and its compounds are very promising HER electrocatalysts owing to their low-cost and abundance. In the thesis, we focused on the preparation and characterization of Mo-based HER electrocatalysts. The main points of the thesis are addressed as follows: 1. We demonstrate the preparation of NixSy-doped MoS2 microspheres (NMSHMs) via one-pot hydrothermal treatment of aqueous solutions of Ni(NO3)2?6H2O, Na2MoO4?2H2O and H2NCSNH2. As an electrocatalyst toward HER, the NMSHMs exhibit superior activity over NixSy, MoS2 and their physical mixture (mNM) in acidic solutions. In addition, we further explored and optimize the amount of Ni species in the products. 2. We demonstrate the synthesis of Mo2C nanoparticles decorated graphitic carbon sheets (Mo2C/GCSs) via a biopolymer-derived reaction between (NH4)6Mo7O24?4H2O and sodium alginate at high temperature in Ar atmosphere. These well-dispersed nanoparticles have sizes in the range of 5-23 nm. The Mo2C/GCSs hybrids exhibit high HER activity and stability in acidic solutions, with a near 100% Faradaic efficiency. The strong conjugation between the anchored Mo2C particles and carbon supports enhances fast electron transport. Besides, the unique carbon sheet-supported nanostructure inhibits the aggregation of Mo2C nanoparticles and exposing large amounts of active sites, resulting in high electrocatalytic activity. 3. An internal oxidation and reduction route was utilized to prepare molybdenum phosphide (MoP). We introduced phosphorous precursor (NaH2PO4?2H2O) to the above experiment system and MoP nanosheets supported on carbon flake were obtained via similar calcination conditions. As novel HER electrocatalysts, such hybrids show superior activity as compared to bulk MoP in both acidic and neutral electrolytes. Carbon species play a key role in reducing phosphorous. To prove this, multi-wall carbon nanotubes were utilized in a similar calcination process and MoP/CNT hybrids were finally obtained. The robust hybrids also operate in H2 producing in acidic and neutral conditions.
语种	中文
公开日期	2016-05-03
内容类型	学位论文
源URL	[http://ir.ciac.jl.cn/handle/322003/64465]
专题	长春应用化学研究所_长春应用化学研究所知识产出_学位论文
推荐引用方式 GB/T 7714	崔伟. 新型钼系复合析氢电催化剂的制备及性能研究[D]. 中国科学院长春应用化学研究所. 中国科学院研究生院. 2015.

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