本文選題：MOFs + 雙金屬磷化物　； 參考：《北京化工大學(xué)》2017年碩士論文

【摘要】：金屬-有機(jī)骨架材料(MOFs)是一種具有多孔結(jié)構(gòu)的晶體復(fù)合材料,它由金屬離子與有機(jī)官能團(tuán)有序配位而成,具有永久的孔結(jié)構(gòu)、大的比表面積、可調(diào)節(jié)的孔徑尺寸等性質(zhì),以上特性使MOFs材料成為一種良好的模板化的復(fù)合材料。此外,金屬離子與有機(jī)基團(tuán)的多樣性,使MOFs材料具有可調(diào)節(jié)的結(jié)構(gòu)及元素組成。作為配體的有機(jī)官能團(tuán)中含有豐富的C、N元素,根據(jù)報道,不同元素之間的摻雜作用會使材料的催化性能得以提高。過渡金屬磷化物具有良好的導(dǎo)電性,是一種已報道的不含貴金屬的電解水的催化劑,在OER和HER催化反應(yīng)中得到廣泛的應(yīng)用。本課題目的在于利用MOFs材料作為模板劑,經(jīng)過磷化反應(yīng)制得相應(yīng)的磷化物催化劑。本實驗中首先利用水熱法,以四水乙酸鈷和乙酰丙酮鎳為金屬離子源、對苯二甲酸為配位劑、PVP為表面活性劑,在DMF和水的混合溶液中合成出了 NiCo-MOF材料。將制得的NiCo-MOF與NaH2PO2反應(yīng)制得表面包覆一層碳膜的顆粒狀的雙金屬磷化物Ni2P-CoP。在0.5M的H2SO4溶液中進(jìn)行HER測試,過電勢為-104mV,Tafel斜率為63mV/dec; 0.1M的KOH溶液進(jìn)行OER活性測試,過電勢為320 mV,Tafel斜率為63mV/dec,并且在HER和OER活性測試中,材料均具有很好的穩(wěn)定性。通過面掃和HRTEM測試,發(fā)現(xiàn)材料中Ni、Co、P是均勻分布,并且Ni2P和CoP是緊密聚集在一起的。對比Ni2P-CoP、Ni2P、CoP、機(jī)械混合的 Ni2P+CoP 的 HER 和 OER 活性,發(fā)現(xiàn)Ni2P-CoP的電解水的活性最好,證明了 Ni2P-CoP中的協(xié)同作用促使其活性優(yōu)于其他催化劑。本實驗中,還制備了一種含有Fe、Ni元素的MOF-5材料。調(diào)節(jié)Fe、Ni元素的摩爾比,發(fā)現(xiàn)材料由立方塊結(jié)構(gòu)變成立方塊8個角處長棒的復(fù)合結(jié)構(gòu),并且發(fā)現(xiàn)當(dāng)Fe/Ni的值越大時棒越粗、數(shù)量越多。BET的測試結(jié)構(gòu)顯示當(dāng)Fe/Ni為1:2時,材料具有最大的比表面積和平均孔徑,分別為507.3 m2/g和14 nm,隨著Fe/Ni的值變大材料的比表面積和平均孔徑都下降。將制備的FeNi-MOF-5與NaH2P02在350 ℃下反應(yīng)3 h,制得Fe、Ni的雙金屬磷化物,發(fā)現(xiàn)材料的形貌能夠保存。在0.5M H2SO4的溶液中進(jìn)行HER活性測試,當(dāng)Fe/Ni為1:2時活性最好過電勢為-254 mV,Tafel斜率為96 mV/dec。
[Abstract]:The metal-organic skeleton material (MOFs) is a kind of crystal composite with porous structure. It is composed of metal ions and organic functional groups, which have permanent pore structure, large specific surface area, adjustable pore size, etc. The above properties make MOFs material a good template composite material. In addition, the diversity of metal ions and organic groups makes MOFs materials have adjustable structure and elemental composition. The organic functional groups as ligands contain abundant Con N elements. According to the reports, doping among different elements will improve the catalytic performance of the materials. Transition metal phosphates have good electrical conductivity and are reported as catalysts for electrolytic water without precious metals. They have been widely used in the catalytic reactions of OER and HER. The purpose of this paper is to prepare phosphates catalyst by phosphating reaction using MOFs material as template. In this experiment, the NiCo-MOF materials were synthesized by hydrothermal method in the mixed solution of DMF and water with cobalt acetate and nickel acetylacetone tetrahydrate as metal ion source and terephthalic acid as coordination agent. The granular bimetallic phosphates Ni2P-CoP coated with a carbon film were prepared by the reaction of the prepared NiCo-MOF with NaH2PO2. The HER test was carried out in 0.5m H2SO4 solution, and the overpotential was -104mV / Tafel slope of 63mV / r, and the OER activity of 0.1M KOH solution was tested. The overpotential was 320mV / t Tafel slope of 63mV / r / decol.And in the HER and OER activity tests, the material had good stability. The results of surface scanning and HRTEM test show that NiCoP is uniformly distributed and that Ni2P and CoP are closely clustered together. Comparing the HER and OER activities of the mechanically mixed Ni2P CoP with Ni2P-CoP, it was found that the electrolysis water of Ni2P-CoP had the best activity, which proved that the synergistic action in Ni2P-CoP promoted its activity to be superior to that of other catalysts. In this experiment, we also prepared a kind of MOF-5 material containing Fe Ni. By adjusting the mole ratio of Fe ~ (2 +) Ni, we found that the material changed from a square structure to a composite structure with eight square angles. It was also found that the bigger the value of Fe/Ni, the thicker the rod, the more the number of Fe/Ni. The test structure showed that when Fe/Ni was 1:2, The material has the largest specific surface area and average pore size, which are 507.3 m2 / g and 14 nm, respectively. The specific surface area and average pore size of the material decrease with the increase of Fe/Ni value. Bimetallic phosphates were prepared by the reaction of FeNi-MOF-5 and NaH2P02 at 350 鈩，

本文編號：1814693