本文選題：Bi_2WO_6 + CoWO_4��； 參考：《溫州大學(xué)》2016年碩士論文

【摘要】：析氧反應(yīng)是電催化分解水的決速步。當(dāng)前用于析氧反應(yīng)的催化劑仍具有成本高、效率低、穩(wěn)定性差等缺點(diǎn)。因此開發(fā)新型電催化劑具有重要意義。鎢酸鹽材料在傳感、發(fā)光、催化、緩蝕等領(lǐng)域有著廣泛的應(yīng)用,但是用于電催化分解水方面鮮有報(bào)導(dǎo)。本論文通過晶面工程、缺陷調(diào)控以及與導(dǎo)電材料復(fù)合策略,顯著提高了三元鎢基材料的電催化析氧性能。論文主要工作如下:(1)以五水合硝酸鉍,二水合鎢酸鈉為原料,以油胺為表面活性劑,采用溶劑熱法,合成了具有氧空位的凹面鎢酸鉍納米片。利用XRD、FE-SEM、TEM、XPS、EDX、紫外-可見漫反射光譜等表征手段對(duì)產(chǎn)物進(jìn)行了形貌和結(jié)構(gòu)表征。所合成的氧空位凹面鎢酸鉍納米片在近中性的條件下具有穩(wěn)定的電化學(xué)分解水產(chǎn)氧性能。據(jù)我們所知,這是第一個(gè)不含第一行過渡金屬及貴金屬的鎢基電催化劑用于近中性析氧反應(yīng)的報(bào)道。實(shí)驗(yàn)結(jié)果和第一性原理表明,氧空位的存在能夠在電化學(xué)過程中減少電荷轉(zhuǎn)移阻力及水分子的吸附阻力,提高了電化學(xué)產(chǎn)氧的活性。此外,凹面的存在也增強(qiáng)了鎢酸鉍納米片的電化學(xué)產(chǎn)氧活性。由于高能晶面和氧空位的協(xié)同效應(yīng),具有氧空位的凹面鎢酸鉍納米片的電化學(xué)產(chǎn)氧性能可以與報(bào)道的最好的無機(jī)非貴金屬催化劑相媲美。缺陷工程與晶面工程相組合的策略為設(shè)計(jì)新型、高效析氧電催化劑開辟了新途徑。(2)以六水合氯化鈷、二水合鎢酸鈉為原料,采用溶劑熱法合成了兩種形貌不同的鎢酸鈷納米材料。通過XRD、FE-SEM、HRTEM、XPS、EDX等分析技術(shù)對(duì)合成的產(chǎn)物進(jìn)行詳盡表征。產(chǎn)物的電化學(xué)產(chǎn)氧性能研究結(jié)果表明:鎢酸鈷納米棒的電化學(xué)產(chǎn)氧性能優(yōu)于鎢酸鈷納米顆粒。經(jīng)過系統(tǒng)分析,兩種不同形貌的電催化劑性能差異主要來自于不同的化學(xué)活性面積。在此基礎(chǔ)上,篩選出性能良好的棒狀鎢酸鈷加入氧化石墨烯,一鍋煮法合成Co WO_4/氮摻雜-還原氧化石墨烯復(fù)合材料。研究結(jié)果表明,由于氮摻雜的還原氧化石墨烯良好的導(dǎo)電性,Co WO_4/氮摻雜-還原氧化石墨烯復(fù)合材料顯示了增強(qiáng)的電催化活性。
[Abstract]:Oxygen evolution is a rapid step in the electrocatalytic decomposition of water. The current catalysts for oxygen evolution still have the disadvantages of high cost, low efficiency and poor stability. Therefore, it is of great significance to develop new electrocatalysts. Tungstate materials have been widely used in sensing, luminescence, catalysis, corrosion inhibition and so on, but they are rarely reported in the field of electrocatalytic decomposition of water. In this paper, the electrocatalytic oxygen evolution of the ternary tungsten based materials is improved significantly by surface engineering, defect control and composite strategy with conductive materials. The main work of this paper is as follows: (1) Bismuth bismuth pentahydrate and sodium tungstate dihydrate were used as raw materials and oleamine as surfactant. Bismuth concave bismuth tungstate nanoparticles with oxygen vacancy were synthesized by solvothermal method. The morphology and structure of the products were characterized by means of XRDX FE-SEMX and UV-Vis diffuse reflectance spectroscopy. The synthesized oxygen vacancy concave bismuth tungstate nanocrystals have stable electrochemical decomposition of aquatic oxygen under near neutral conditions. To our knowledge, this is the first tungsten based electrocatalyst without the first row of transition metals and precious metals for near-neutral oxygen evolution. The experimental results and first principles show that the presence of oxygen vacancies can reduce the charge transfer resistance and the adsorption resistance of water molecules in the electrochemical process and improve the electrochemical oxygen production activity. In addition, the presence of concave surface also enhanced the electrochemical oxygen production activity of bismuth tungstate nanoparticles. Due to the synergistic effect of high energy crystal plane and oxygen vacancy, the electrochemical oxygen production performance of concave bismuth tungstate nanocrystalline with oxygen vacancy is comparable to that of the best inorganic non-noble metal catalyst reported. The strategy of the combination of defect engineering and crystal plane engineering opens up a new way for the design of new and efficient oxygen evolution electrocatalysts. It uses cobalt chloride hexahydrate and sodium tungstate dihydrate as raw materials. Two kinds of cobalt tungstate nanomaterials with different morphologies were synthesized by solvothermal method. The synthesized products were characterized in detail by XRDX FE-SEMX HRTEMN XPS edX and other analytical techniques. The results show that the electrochemical oxygen production of cobalt tungstate nanorods is better than that of cobalt tungstate nanoparticles. Through systematic analysis, the difference of the performance of the two kinds of electrocatalysts with different morphology mainly comes from the different chemical active area. On this basis, Co WO_4/ nitrogen-reductive graphene oxide composites were synthesized by one-pot boiling method, in which the rod-like cobalt tungstate was added into graphene oxide. The results show that the nitrogen-doped reduced graphene oxide composite exhibits enhanced electrocatalytic activity due to its good electrical conductivity Co WO_4/ nitrogen-reduced graphene oxide composite.
【學(xué)位授予單位】：溫州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O643.36

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本文編號(hào)：1828537