鎢基化合物的制備、表征及催化性能研究
發(fā)布時間：2018-08-10 07:41
【摘要】：隨著能源危機和環(huán)境污染問題日益加劇,可再生能源的開發(fā)迫在眉睫。太陽能是一種最具開發(fā)利用潛力的可再生能源。作為第三代太陽能電池,染料敏化太陽能電池(dye-sensitized solar cell,DSSC)由于其原材料來源廣泛、制備成本低廉、制作工藝簡單、環(huán)境友好和理論轉(zhuǎn)化效率較高等優(yōu)點,一直是國內(nèi)外研究的熱點。作為DSSC的重要組成部分,對電極主要負責(zé)收集外部電路電子以及催化還原電解質(zhì)溶液中的I3-離子。Pt是最常用的對電極催化材料。然而,其價格昂貴且儲量有限,嚴重限制了DSSC的商業(yè)化應(yīng)用。因此,開發(fā)低成本、高催化性能的非鉑對電極材料,具有重要的意義。鎢基過渡金屬化合物由于其充足的資源儲備量、良好的離子和電子導(dǎo)電性、較強的催化活性及目標(biāo)產(chǎn)物的可選擇性,使其作為對電極催化劑材料在DSSC中顯示出巨大的應(yīng)用潛力。本文通過不同的制備方法合成了鎢基化合物對電極催化材料,并將其應(yīng)用于DSSC中。針對由鎢基化合物作為對電極的DSSC進行了以下研究。(1)利用簡單化學(xué)“一鍋法”,成功制備一元鎢基化合物(W_(18)O_(49)、WO_3和W_2N)電催化材料,并系統(tǒng)考察了其作為對電極催化劑在DSSC中的催化性能。研究結(jié)果表明:所制備的鎢基化合物材料結(jié)晶度較好、物相純度較高及尺寸分布均勻。鎢基化合物對電極具有優(yōu)秀的電化學(xué)性能與光伏性能。作為表征對電極催化劑催化性能的參數(shù),W_2N、WC和WO_3的傳荷電阻分別為20.04Ω,22.18Ω和25.32Ω,對應(yīng)DSSC的光電能量轉(zhuǎn)換效率分別為5.97%,5.20%和4.69%,相似于相同條件下的Pt對電極(10.81Ω,6.52%)。由于氧空位的引入,非化學(xué)計量比的W_(18)O_(49)獲得了最優(yōu)的催化性能(傳荷電阻為2.52Ω),對應(yīng)DSSC表現(xiàn)出最優(yōu)的光伏性能(6.69%)。同時,電化學(xué)穩(wěn)定性測試結(jié)果顯示W(wǎng)_(18)O_(49)、W_2N、WC和WO_3可以穩(wěn)定高效地催化還原I-/I3-。第一性原理密度泛函理論計算結(jié)果表明:W_(18)O_(49),W_2N,WC和Pt的帶隙為零,而WO_3的帶隙為1.7eV,這進一步闡明了影響鎢基化合物優(yōu)異電催化活性的本征因素。(2)利用低溫水熱法,合成了二元鎢基化合物Ni_(0.19)WO_4和CoWO_4電催化材料。實驗結(jié)果表明:所制備的Ni_(0.19)WO_4和CoWO_4材料具有組成均一且結(jié)晶性良好的特點。Ni_(0.19)WO_4和CoWO_4對電極顯示了相近的串聯(lián)電阻(16.21Ω和14.36Ω)和傳荷電阻(35.08Ω和41.18Ω),即Ni_(0.19)WO_4與CoWO_4對I-/I3-有良好的催化性能�；贜i_(0.19)WO_4和CoWO_4對電極的DSSC,獲得光電能量轉(zhuǎn)換效率分別為4.71%和4.55%,而同等條件下的Pt對電極的光電能量轉(zhuǎn)換效率為6.27%。同時,電化學(xué)穩(wěn)定性測試表明Ni_(0.19)WO_4和CoWO_4表現(xiàn)出良好的電化學(xué)穩(wěn)定性。(3)利用均相共沉積法,成功的合成了Fe_2WO_4電催化材料。實驗結(jié)果表明:所制備的Fe_2WO_4材料的粒度均勻且純度較高。由Fe_2WO_4對電極組成的對稱電池,其串聯(lián)電阻與傳荷電阻分別為16.1Ω和27.42Ω,對應(yīng)DSSC的光電能量轉(zhuǎn)換效率5.17%。Fe_2WO_4對電極利用了雙金屬間的協(xié)同作用,表現(xiàn)出了可與Pt電極相比的催化性能。同時,Fe_2WO_4對電極在I-/I3-電解液中具有優(yōu)異的電化學(xué)穩(wěn)定性。
[Abstract]:As the energy crisis and environmental pollution are increasing, the development of renewable energy is imminent. The solar energy is the most potential renewable energy. As the third generation of solar cells, the dye sensitized solar cell (dye-sensitized solar cell, DSSC) is widely used in the raw materials, and the production cost is low. As an important part of DSSC, the main responsibility of collecting the external circuit electrons and the I3- ion.Pt in the catalytic reductive electrolyte solution is the most commonly used electrode accelerating material. However, its price is expensive and the reserves are limited. The commercialized application of DSSC is seriously restricted. Therefore, it is of great significance to develop the non platinum electrode materials with low cost and high catalytic performance. The tungsten based transition metal compounds are used as the electrode catalysts due to their sufficient reserve of resources, good ionic and electronic conductivity, strong catalytic activity and the selectivity of the target products. Materials have shown great potential for application in DSSC. In this paper, tungsten based compounds have been synthesized by different preparation methods and applied to the DSSC. The following studies have been made for the DSSC of the tungsten based compounds as the electrode. (1) a single tungsten based compound (W_ (18) O_) was successfully prepared by the simple chemical "one pot" method. (49) (49), WO_3 and W_2N) electrocatalytic materials and their catalytic performance as an electrode catalyst in DSSC. The results show that the prepared tungsten based compounds have good crystallinity, high phase purity and uniform size distribution. The parameters of the catalytic performance of the catalyst, W_2N, WC and WO_3, are 20.04 Omega, 22.18 omega and 25.32 Omega respectively. The photoelectric energy conversion efficiency of the corresponding DSSC is 5.97%, 5.20% and 4.69% respectively, similar to the Pt pair electrode (10.81 Omega, 6.52%) under the same condition. The non stoichiometric ratio of W_ (18) O_ (49) is obtained because of the introduction of the oxygen vacancy. The catalytic performance (transfer resistance is 2.52 omega) shows the best photovoltaic performance (6.69%) corresponding to DSSC. At the same time, the results of electrochemical stability test show that W_ (18) O_ (49), W_2N, WC and WO_3 can stabilize and efficiently catalyze the reduction of I-/I3-. first principle density functional theory calculation results show that W_ (18) O_ (49), W_2N, WC, and Pt band gap is zero. The band gap is 1.7eV, which further clarifies the intrinsic factors affecting the excellent electrocatalytic activity of tungsten based compounds. (2) a two element tungsten base compound, Ni_ (0.19) WO_4 and CoWO_4, is synthesized by low temperature hydrothermal method. The experimental results show that the prepared Ni_ (0.19) WO_4 and CoWO_4 materials have a homogeneous and good crystallization characteristic.Ni_ (0.1). 9) WO_4 and CoWO_4 show similar series resistance (16.21 omega and 14.36 omega) and transfer resistance (35.08 omega and 41.18 omega), that is, Ni_ (0.19) WO_4 and CoWO_4 have good catalytic performance to I-/I3-. Based on Ni_ (0.19) WO_4 and CoWO_4 pairs of DSSC, the photoelectric energy conversion efficiency is 4.71% and 4.55% respectively, and the Pt pair electrode under the same condition The photoelectric energy conversion efficiency was 6.27%., and the electrochemical stability test showed that Ni_ (0.19) WO_4 and CoWO_4 showed good electrochemical stability. (3) the Fe_2WO_4 electrocatalysis material was successfully synthesized by homogeneous co deposition. The experimental results showed that the prepared Fe_2WO_4 material had a uniform particle size and high purity. The Fe_2WO_4 pair was used as the electrode. The symmetrical battery consists of 16.1 omega and 27.42 Omega resistance in series resistance and transfer resistance, respectively, and the photoelectrical energy conversion efficiency of the corresponding DSSC 5.17%.Fe_2WO_4 makes use of the synergism between the bimetallic electrode, showing the catalytic performance compared with the Pt electrode. At the same time, the Fe_2WO_4 has excellent electrochemical stability in the I-/I3- electrolyte. Sex.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O643.36;TM914.4
本文編號：2175411
[Abstract]:As the energy crisis and environmental pollution are increasing, the development of renewable energy is imminent. The solar energy is the most potential renewable energy. As the third generation of solar cells, the dye sensitized solar cell (dye-sensitized solar cell, DSSC) is widely used in the raw materials, and the production cost is low. As an important part of DSSC, the main responsibility of collecting the external circuit electrons and the I3- ion.Pt in the catalytic reductive electrolyte solution is the most commonly used electrode accelerating material. However, its price is expensive and the reserves are limited. The commercialized application of DSSC is seriously restricted. Therefore, it is of great significance to develop the non platinum electrode materials with low cost and high catalytic performance. The tungsten based transition metal compounds are used as the electrode catalysts due to their sufficient reserve of resources, good ionic and electronic conductivity, strong catalytic activity and the selectivity of the target products. Materials have shown great potential for application in DSSC. In this paper, tungsten based compounds have been synthesized by different preparation methods and applied to the DSSC. The following studies have been made for the DSSC of the tungsten based compounds as the electrode. (1) a single tungsten based compound (W_ (18) O_) was successfully prepared by the simple chemical "one pot" method. (49) (49), WO_3 and W_2N) electrocatalytic materials and their catalytic performance as an electrode catalyst in DSSC. The results show that the prepared tungsten based compounds have good crystallinity, high phase purity and uniform size distribution. The parameters of the catalytic performance of the catalyst, W_2N, WC and WO_3, are 20.04 Omega, 22.18 omega and 25.32 Omega respectively. The photoelectric energy conversion efficiency of the corresponding DSSC is 5.97%, 5.20% and 4.69% respectively, similar to the Pt pair electrode (10.81 Omega, 6.52%) under the same condition. The non stoichiometric ratio of W_ (18) O_ (49) is obtained because of the introduction of the oxygen vacancy. The catalytic performance (transfer resistance is 2.52 omega) shows the best photovoltaic performance (6.69%) corresponding to DSSC. At the same time, the results of electrochemical stability test show that W_ (18) O_ (49), W_2N, WC and WO_3 can stabilize and efficiently catalyze the reduction of I-/I3-. first principle density functional theory calculation results show that W_ (18) O_ (49), W_2N, WC, and Pt band gap is zero. The band gap is 1.7eV, which further clarifies the intrinsic factors affecting the excellent electrocatalytic activity of tungsten based compounds. (2) a two element tungsten base compound, Ni_ (0.19) WO_4 and CoWO_4, is synthesized by low temperature hydrothermal method. The experimental results show that the prepared Ni_ (0.19) WO_4 and CoWO_4 materials have a homogeneous and good crystallization characteristic.Ni_ (0.1). 9) WO_4 and CoWO_4 show similar series resistance (16.21 omega and 14.36 omega) and transfer resistance (35.08 omega and 41.18 omega), that is, Ni_ (0.19) WO_4 and CoWO_4 have good catalytic performance to I-/I3-. Based on Ni_ (0.19) WO_4 and CoWO_4 pairs of DSSC, the photoelectric energy conversion efficiency is 4.71% and 4.55% respectively, and the Pt pair electrode under the same condition The photoelectric energy conversion efficiency was 6.27%., and the electrochemical stability test showed that Ni_ (0.19) WO_4 and CoWO_4 showed good electrochemical stability. (3) the Fe_2WO_4 electrocatalysis material was successfully synthesized by homogeneous co deposition. The experimental results showed that the prepared Fe_2WO_4 material had a uniform particle size and high purity. The Fe_2WO_4 pair was used as the electrode. The symmetrical battery consists of 16.1 omega and 27.42 Omega resistance in series resistance and transfer resistance, respectively, and the photoelectrical energy conversion efficiency of the corresponding DSSC 5.17%.Fe_2WO_4 makes use of the synergism between the bimetallic electrode, showing the catalytic performance compared with the Pt electrode. At the same time, the Fe_2WO_4 has excellent electrochemical stability in the I-/I3- electrolyte. Sex.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O643.36;TM914.4
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