本文選題：析氫反應(yīng) + 析氧反應(yīng)　； 參考：《山東師范大學》2017年碩士論文

【摘要】：隨著能源危機和濫用化石燃料帶來的空氣污染和全球變暖等問題的加劇,發(fā)展高效清潔的可再生能源刻不容緩。在眾多的可再生能源中,氫氣以其環(huán)境友好性和高能量密度等優(yōu)勢被視為極具發(fā)展?jié)摿Φ男滦蜐崈裟茉�。在現(xiàn)有的制氫途徑中,將電能轉(zhuǎn)化為氫能的電解水過程被認為是一種高效、經(jīng)濟和環(huán)保的方式。常溫常壓下,電解水所需的理論電壓窗口為1.23 V。然而在實際操作中,為了降低電極反應(yīng)所需的過電勢,使用電催化劑作為電極材料是當前公認的效率提升策略。在現(xiàn)有的催化劑中,基于貴金屬的催化劑具有最高的催化效率,但其元素稀缺性和昂貴的價格極大限制了其工業(yè)應(yīng)用可能,因此,開發(fā)高效廉價的電催化劑勢在必行。在本論文中,作者以高豐度的過渡金屬化合物作為研究對象,通過缺陷工程、無序結(jié)構(gòu)工程、元素摻雜以及與導電材料復合等方式對催化劑的活性位點和導電性進行了優(yōu)化,實現(xiàn)了催化性能的顯著提升。該論文對未來電催化劑的設(shè)計與發(fā)展提供了指導性作用。本論文包括以下兩個內(nèi)容:1.作者利用元素摻雜、無序結(jié)構(gòu)工程以及材料復合等方法制備出了垂直生長在碳布上的氧摻雜二硫化鉬電催化劑,實現(xiàn)了活性位點和導電性的協(xié)同優(yōu)化,獲得了顯著提升的析氫反應(yīng)活性。在該復合電催化劑中,高度無序的MoS2納米片提供了豐富的催化活性位點,氧摻雜以及與碳材料的復合賦予了材料優(yōu)越的導電性,使更多的活性位點能夠?qū)崿F(xiàn)電學連通,有效地參與到催化過程中,最終實現(xiàn)了析氫反應(yīng)性能的協(xié)同優(yōu)化提升。協(xié)同優(yōu)化后的氧摻雜MoS2/碳布催化劑顯示出超低的起始過電位、優(yōu)越的催化電流密度以及良好的穩(wěn)定性。在本工作中提出的協(xié)同優(yōu)化策略為新型電催化劑的設(shè)計提供了可供借鑒的方法。2.作者利用三元NiFe Zn層狀氫氧化物(ZnNiFe LDH)為前驅(qū)物,通過刻蝕—熟化的方法制備出了含有大量直徑約為2~3 nm的納米孔的NiFe LDH超薄納米篩,實現(xiàn)了析氧反應(yīng)性能的顯著提高。三元前驅(qū)物中兩性的Zn離子可以通過強堿處理的方式被選擇性刻蝕,實現(xiàn)了片內(nèi)的初步成孔,而隨后的熟化過程使納米孔的孔徑實現(xiàn)均勻化。納米孔的引入能夠促進具有催化活性的高價態(tài)物質(zhì)的產(chǎn)生,提供更多的位點用于析氧反應(yīng)。此外,納米孔提供的空隙能夠有效避免反復的氧化還原過程中的結(jié)構(gòu)破壞,賦予材料優(yōu)越的電化學穩(wěn)定性,使其有望用于工業(yè)水分解。這個工作為析氧反應(yīng)性能的優(yōu)化提供了有效的策略,并為今后電催化劑的設(shè)計提供了啟發(fā)。
[Abstract]:With the problems of energy crisis, air pollution caused by fossil fuel abuse and global warming, it is urgent to develop efficient and clean renewable energy. Among the many renewable energy sources, hydrogen is regarded as a new clean energy with great potential due to its environmental friendliness and high energy density. In the existing hydrogen production process, the process of converting electric energy into hydrogen energy is considered to be an efficient, economical and environmentally friendly way. At room temperature and atmospheric pressure, the theoretical voltage window for electrolytic water is 1.23 V. In practice, however, in order to reduce the overpotential of electrode reaction, it is widely accepted that the electrocatalyst is used as electrode material. Among the existing catalysts, the catalysts based on noble metals have the highest catalytic efficiency, but their rare elements and expensive prices greatly limit their industrial applications. Therefore, it is imperative to develop efficient and cheap electrocatalysts. In this thesis, the transition metal compounds with high abundance were used to optimize the active sites and conductivity of the catalysts by defect engineering, disordered structure engineering, element doping and composite with conductive materials. The catalytic performance was improved remarkably. This paper provides guidance for the design and development of electrocatalysts in the future. This thesis includes two parts as follows: 1. The oxygen doped molybdenum disulfide electrocatalysts grown vertically on carbon cloth were prepared by elemental doping, disordered structure engineering and material recombination. The cooperative optimization of active sites and conductivity was achieved. The activity of hydrogen evolution reaction was improved significantly. In the composite electrocatalyst, the highly disordered MoS2 nanoparticles provide abundant catalytic active sites, and oxygen doping and the compounding with carbon materials give the materials superior electrical conductivity, so that more active sites can be electrically connected. It can effectively participate in the catalytic process and finally realize the synergistic optimization of the hydrogen evolution reaction performance. Co-optimized oxygen doped MoS2/ carbon cloth catalysts show ultra-low initial overpotential, superior catalytic current density and good stability. The cooperative optimization strategy proposed in this work provides a reference method for the design of new electrocatalysts. Using ternary NiFe Zn layered hydroxide (ZnNiFe LDH) as precursor, NiFe LDH ultrathin nano-sieve containing a large number of nano-pores (about 2nm in diameter) was prepared by etching and ripening method, and the oxygen evolution reaction performance was improved remarkably. The amphoteric Zn ion in the ternary precursor can be selectively etched by strong alkali treatment, and the initial pore formation is realized, and the pore size is homogenized by subsequent ripening process. The introduction of nano-pores can promote the production of high-valence compounds with catalytic activity and provide more sites for oxygen evolution. In addition, the pores provided by the nano-pores can effectively avoid the structural damage during the repeated redox process, and give the material excellent electrochemical stability, which is expected to be used in the decomposition of industrial water. This work provides an effective strategy for the optimization of oxygen evolution reaction performance and provides inspiration for the design of electrocatalysts in the future.
【學位授予單位】：山東師范大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O643.36;TQ116.21
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本文編號：1862415