二维二硫化钼基复合催化剂的制备及其光电催化析氢性能研究

发布时间：2018-04-27 07:43

本文选题：二硫化钼 + 光电化学析氢　；参考：《北京化工大学》2017年硕士论文

【摘要】：近年来,能源稀缺、环境破坏、气候变化已成为国际上各国最为关注的核心问题。为了应对全球气候和生态的变化,构建以可持续能源和新能源为主体的可再生能源系统势在必行。氢气燃烧产物为水,这既不会导致空气污染,又不会导致温室效应,因此人们常把氢能作为可再生的环境友好未来能源。光电催化析氢反应因其效率高、工艺简单等优点是制备氢气的高效途径之一,但传统的光电催化析氢材料对光的利用率比较低,能耗高,因此设计和开发高光利用率、低过电位的光电催化析氢催化剂成为研究的焦点。窄带隙的二维二硫化钼(MoS_2)已经被证明是析氢活性接近贵金属Pt的二维非金属阴极催化剂,但其导电性差、边缘活性位点少以及光生电子和空穴易复合等限制了它的广泛应用和发展。本论文为了克服以上二硫化钼存在的缺点,设计制备了二硫化钼基复合催化剂,并研究了所制备二硫化钼基复合催化剂的光电催化性能。本文的具有研究成果如下:采用简单易行的一步水热法制备了 MoS_2/N-rGO (掺氮的还原氧化石墨烯)阴极催化催化剂,N-rGO的引入提高了电极材料的导电性,加快了电荷分离和转移效率。光电化学测试结果表明:在酸性体系中,与单独的MoS_2相比,MoS_2/N-rGO复合催化剂具有更加优异的电析氢活性,但其光催化析氢性能不明显。针对二硫化钼光生载流子容易复合的问题,设计合成了一种价格低廉、性能优异的MoS_2/In_2S_3电极材料。催化剂MoS_2和In_2S_3能够形成纳米尺寸的异质结结构,极大地加快电荷的产生,极大地降低了光生电子和空穴的复合,进而提高光电催化析氢性能。对MoS_2、IIn_2S_3和MoS_2/In_2S_3三种催化剂进行性能测试,结果表明MoS_2/In_2S_3拥有更加卓越的析氢性能以及更大的有效活性电化学面积(ECSA)和更小的塔菲尔斜率。通过调节前驱体钼酸钠和氯化铟的比例,调控MoS_2/In_2S_3催化剂的形貌结构,结果显示,钼、铟前驱体比例为1:2时制备的MoS_2/IIn_2S_3样品光电析氢性能最优。以钥酸钠和钨酸钠为前驱体,采用水热法合成一种花瓣状纳米片MoS_2/WS_2复合催化剂,与单独的MoS_2、WS_2相比,MoS_2/WS_2样品对可见光的吸收范围更宽和强度更大。光电催化析氢测试结果表明在MoS_2和WS_2的协同作用下MoS_2/WS_2催化剂表现出优异的光电析氢性能。探究了不同钼、钨前驱体比例对产物MoS_2/WS_2光电催化性能的影响,结果表明钼、钨前驱体比例为1:1的MoS_2/WS_2样品的电催化和光催化性能均最佳。
[Abstract]:In recent years, energy scarcity, environmental damage, climate change has become the most international concern of the core issues. In order to cope with the change of global climate and ecology, it is imperative to construct renewable energy system with sustainable energy and new energy as the main body. The hydrogen combustion product is water, which causes neither air pollution nor Greenhouse Effect, so hydrogen is often used as a renewable and environmentally friendly energy source for the future. Photocatalytic hydrogen evolution reaction is one of the efficient ways to produce hydrogen because of its high efficiency and simple process. However, the traditional photocatalytic hydrogen evolution materials have low utilization ratio of light and high energy consumption, so the high light utilization ratio is designed and developed. Low overpotential photocatalytic hydrogen evolution catalyst has become the focus of research. The narrow band gap 2-D molybdenum disulfide (MoS _ 2) has been proved to be a 2-D non-metallic cathode catalyst with hydrogen evolution activity close to that of noble metal Pt, but its electrical conductivity is poor. Its wide application and development are limited by the low number of edge active sites and the easy recombination of photogenerated electrons and holes. In order to overcome the shortcomings of the above mentioned molybdenum disulfide composite catalysts were designed and prepared. The photocatalytic properties of the prepared molybdenum disulfide based composite catalysts were studied. The results of this paper are as follows: the introduction of N-rGO (nitrogen-doped reductive graphene) cathode catalyst has improved the conductivity of the electrode material and accelerated the charge separation and transfer efficiency by using a simple, one-step hydrothermal method to prepare MoS_2/N-rGO (reduced graphene oxide) cathode catalyst. The photochemical results show that compared with MoS_2 alone, MoS _ 2 / N-rGO composite catalyst has more excellent electrohydrogen evolution activity, but its photocatalytic hydrogen evolution performance is not obvious. Aiming at the easy recombination of photogenerated carriers of molybdenum disulfide, a low cost and excellent performance MoS_2/In_2S_3 electrode material was designed and synthesized. The catalyst MoS_2 and In_2S_3 can form nanoscale heterojunction structure, greatly accelerate the generation of charge, greatly reduce the combination of photogenerated electrons and holes, and then improve the photocatalytic hydrogen evolution performance. The performance tests of three kinds of catalysts, MoS2Che / IInS _ 3 and MoS_2/In_2S_3, show that MoS_2/In_2S_3 has better hydrogen evolution performance, larger active electrochemical area and smaller Taffel slope. By adjusting the ratio of sodium molybdate to indium chloride, the morphology and structure of MoS_2/In_2S_3 catalyst were regulated. The results showed that the MoS_2/IIn_2S_3 sample prepared by 1:2 ratio of molybdenum and indium precursor had the best photoelectric hydrogen evolution performance. A petal-like nanochip MoS_2/WS_2 composite catalyst was synthesized by hydrothermal method using sodium key acid and sodium tungstate as precursors. Compared with the single MSS _ 2S _ 2, the absorption range and intensity of visible light of the sample were wider and larger than those of the single MSS _ 2S _ (2) / S _ (2) S _ (2) / S _ (2) S _ (2). The results of photocatalytic hydrogen evolution test showed that the MoS_2/WS_2 catalyst exhibited excellent photocatalytic hydrogen evolution performance under the synergistic action of MoS_2 and WS_2. The effects of different ratios of molybdenum and tungsten precursors on the photocatalytic properties of the product MoS_2/WS_2 were investigated. The results showed that the electrocatalytic and photocatalytic properties of MoS_2/WS_2 samples with the molar and tungsten precursor ratios of 1:1 were the best.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TQ116.2

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