本文選題：單極脈沖法 + 鎳鈷層狀雙金屬氫氧化物�。� 參考：《太原理工大學(xué)》2017年碩士論文

【摘要】：能源危機(jī)和環(huán)境污染是目前全球亟待解決的兩大問題,在此背景下,探索與發(fā)展新型清潔能源以及高效處理水體污染已成為科學(xué)研究的重要課題。層狀雙金屬氫氧化物(Layered Double Hydroxides,簡稱LDHs,俗稱類水滑石),是一種陰離子型的功能材料,具有納米片層狀形貌、并且其位于層間的陰離子可與其他陰離子進(jìn)行交換。最近人們廣泛研究LDH材料的結(jié)構(gòu)和性能,探索其在催化、超級(jí)電容器、鋰離子電池、水處理等方面的應(yīng)用。LDH是一種主客體材料,主體是帶正電荷的層板,是金屬氫氧化物,客體是位于層間的陰離子和自由水分子。由于層狀雙金屬氫氧化物獨(dú)特的層狀結(jié)構(gòu),使其具有較大的比表面積,用作超級(jí)電容器電極材料時(shí),可以同時(shí)發(fā)揮雙電層與贗電容兩種性質(zhì)的電容性能,從而獲得相對(duì)較高的電容量;又由于層狀雙金屬氫氧化物的層間陰離子具有可交換性,可以通過陰離子和功能性配體交換與其他離子形成配合物而應(yīng)用在水處理領(lǐng)域。本文旨在用一種新型的電化學(xué)方法合成鎳鈷層狀雙金屬氫氧化物(NiCo LDH)和其衍生的鎳鈷氧化物(NiCo CLDH)材料。本工作系統(tǒng)研究了NiCo LDH的超級(jí)電容器性能,此外由于NiCo LDH焙燒后具有“記憶效應(yīng)”和更高的電活性,故將其用作電控離子交換(ESIX)膜材料,并且評(píng)價(jià)了其對(duì)磷酸根離子的回收性能。首先,使用單極脈沖電沉積法在碳紙基體上成功制備了NiCo LDH電極材料。考察了不同Ni~(2+)/Co~(2+)摩爾比的制膜液對(duì)合成材料的結(jié)構(gòu)和性能的影響,發(fā)現(xiàn)合成NiCo LDH的形貌組成和性能與制膜液中Ni~(2+)/Co~(2+)摩爾比密切相關(guān)。當(dāng)制膜液中Ni~(2+)/Co~(2+)摩爾比為9:1時(shí),制得的電極材料(Ni_(0.76)Co_(0.24) LDH)形貌更均勻,納米片尺寸更小,比表面積更大,具有較好的電容性能。通過對(duì)Ni_(0.76)Co_(0.24) LDH進(jìn)行循環(huán)伏安測(cè)試、充放電測(cè)試、穩(wěn)定性測(cè)試和交流阻抗測(cè)試得出:在1.0 A g~(-1)的電流密度下比電容高達(dá)2189.8 F g~(-1),且在50 A g~(-1)電流密度下進(jìn)行20000次的恒電流充放電穩(wěn)定性測(cè)試后比電容保持初始值的70.3%,其電荷轉(zhuǎn)移電阻只有0.53Ω。以Ni_(0.76)Co_(0.24) LDH為正極,活性炭為負(fù)極組裝成非對(duì)稱型超級(jí)電容器,測(cè)試其電化學(xué)性能。測(cè)得非對(duì)稱電容器的比電容可達(dá)到179.4 F g~(-1),在4.1 Wh Kg~(-1)的能量密度下,非對(duì)稱電容器的功率密度高達(dá)4000 W Kg~(-1),并且在10 A g~(-1)電流密度下進(jìn)行20000次充放電穩(wěn)定性測(cè)試后,比電容仍保留初始值的82.7%。這表明Ni_(0.76)Co_(0.24) LDH電極具有良好的電容器性能,適合選作超級(jí)電容器電極材料。其次,合成的Ni_(0.76)Co_(0.24) LDH在管式爐中300℃下焙燒2 h,分別考察焙燒前后材料的電化學(xué)活性能,發(fā)現(xiàn)焙燒后膜電極材料的電活性提高。NiCo LDH和焙燒的NiCo LDH(即NiCo CLDH)被用作電控離子交換膜材料,分別測(cè)試其對(duì)PO_4~(3-)離子的吸附性能。實(shí)驗(yàn)表明,在0.8 V吸附電位下,NiCo LDH和NiCo CLDH膜電極分別對(duì)濃度為100 mg L~(-1)的PO_4~(3-)離子吸附6 h,NiCo CLDH膜電極對(duì)PO_4~(3-)離子吸附量達(dá)到225.7 mg g~(-1),而NiCo LDH的吸附量僅為166.6 mg g~(-1)。此后將NiCo CLDH膜材料在濃度均為100 mg L~(-1)的PO_4~(3-),SO_4~(2-)和Br~-的混合溶液中0.8 V吸附電位下同時(shí)吸附,測(cè)試膜材料的吸附選擇性,測(cè)得對(duì)PO_4~(3-)的吸附量遠(yuǎn)遠(yuǎn)高于對(duì)SO_4~(2-)和Br~-的吸附量。另外本工作對(duì)吸附飽和的NiCo CLDH膜材料進(jìn)行PO_4~(3-)離子脫附回收測(cè)試,結(jié)果表明在-0.4 V電位下脫附6 h后,由于NiCo CLDH的記憶效應(yīng),首次脫附率只有81.2%,但是在經(jīng)過五次循環(huán)吸脫附后,吸附量仍高達(dá)160.2 mg g~(-1),而脫附率則上升為98.4%。此工作表明NiCo CLDH具有良好的PO_4~(3-)離子回收性能。
[Abstract]:The energy crisis and the environmental pollution are the two major problems to be solved in the world. In this context, the exploration and development of new clean energy and the efficient treatment of water pollution have become an important subject of scientific research. The layered double metal hydroxide (Layered Double Hydroxides, LDHs, commonly known as hydrotalcite) is an anionic power Energy materials, with nanoscale lamellar morphology, and their interlayer anions can exchange with other anions. Recently, the structure and properties of LDH materials have been extensively studied, and the application of.LDH in catalysis, supercapacitors, lithium ion batteries and water treatment is a kind of host material, and the main body is a positive charge laminar plate. Metal hydroxide, the object is an interlayer of anions and free water molecules. Due to the unique layered structure of layered double metal hydroxide, it has a larger specific surface area. When used as a supercapacitor electrode material, it can perform two kinds of capacitive properties at the same time, such as double layer and pseudopotential, so as to obtain relatively high capacitance. As the interlayer anion of layered double metal hydroxide is exchangeable, it can be used in the field of water treatment by exchanging anions and functional ligands with other ions to form complexes. The purpose of this paper is to synthesize nickel cobalt layered double gold hydroxide (NiCo LDH) and its derived nickel cobalt oxygen by a new electrochemical method. NiCo CLDH material. The performance of the supercapacitor of NiCo LDH is studied in this work system. In addition, because of "memory effect" and higher electrical activity after NiCo LDH roasting, it is used as an electronically controlled ion exchange (ESIX) membrane material, and the recovery performance of the phosphate ion is evaluated. First, the use of monopole electrodeposition is used in the system. The NiCo LDH electrode material was successfully prepared on the carbon paper matrix. The influence of the film solution of different Ni~ (2+) /Co~ (2+) molar ratio on the structure and properties of the synthetic material was investigated. It was found that the morphology and properties of the synthesized NiCo LDH were closely related to the Ni~ (2+) /Co~ (2+) molar ratio in the film liquid. The electrode material (Ni_ (0.76) Co_ (0.24) LDH) has more uniform morphology, smaller size, larger surface area and better capacitance. Through the cyclic voltammetric test of Ni_ (0.76) Co_ (0.24) LDH, charge discharge test, stability test and AC impedance test, it is found that the capacitance is up to 2189.8 F g~ (-1) under the current density of 1 A g~ (-1). After a 20000 constant current charge discharge stability test under 50 A g~ (-1) current density, the initial value of the charge discharge is 70.3%, the charge transfer resistance is only 0.53 Omega. Ni_ (0.76) Co_ (0.24) LDH is the positive pole, the active carbon is assembled into a negative electrode to form an asymmetric super electric container, and its electrochemical performance is tested. The ratio of the asymmetric capacitor is measured. The capacitance can reach 179.4 F g~ (-1). Under the energy density of 4.1 Wh Kg~ (-1), the power density of the asymmetrical capacitor is up to 4000 W Kg~ (-1), and after the 20000 charge discharge stability test under the 10 A g~ (-1) current density, the specific capacitance still keeps the initial value of 82.7%. This indicates that the electrode (0.76) (0.24) has a good capacitance. Ni_ (0.76) Co_ (0.24) LDH was baked for 2 h at 300 C in tube furnace, and the electrochemical activity of the materials before and after baking was investigated. It was found that the electrical activity of the film electrode material after roasting was improved by.NiCo LDH and the roasted NiCo LDH (NiCo CLDH) was used as an electronically controlled ion exchange membrane material. The adsorption properties of PO_4~ (3-) ions are not tested. The experiments show that the adsorption capacity of NiCo LDH and NiCo CLDH membrane electrodes is 6 for PO_4~ (3-) ions with a concentration of 100 mg L~ (-1) at 0.8 V adsorption potential. DH membrane materials are adsorbed at the same concentration of 100 mg L~ (-1) in PO_4~ (3-), SO_4~ (2-) and Br~- in a mixed solution of 0.8 V. The adsorption selectivity of the membrane material is measured. The adsorption capacity of PO_4~ (3-) is far higher than that of the adsorbent and the adsorption capacity of the adsorbent saturated membrane material. The desorption recovery test showed that after the desorption of 6 h at -0.4 V potential, the first desorption rate was only 81.2% due to the memory effect of NiCo CLDH, but after five cycles of desorption, the adsorption amount was still up to 160.2 mg g~ (-1), while the desorption rate increased to 98.4%., which showed that NiCo CLDH had a good recycling performance of PO_4~.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O611.64;TM53

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本文編號(hào)：1957951