本文選題：等離子體 + 金屬磷化物��； 參考：《大連理工大學(xué)》2011年博士論文

【摘要】：過渡金屬磷化物作為一類新型半導(dǎo)體材料可廣泛應(yīng)用于光電、磁、催化等領(lǐng)域。金屬磷化物作為催化劑常采用程序升溫還原法制備,但該法制備溫度高,磷物種易損失,且高溫制備容易導(dǎo)致催化劑顆粒燒結(jié)。本論文用氫等離子體還原法(PR)制備了一系列過渡金屬磷化物,考察并優(yōu)化了磷化鎳(Ni2P)、磷化鉆(CoP)、磷化鉬(MoP)和磷化鎢(WP)的制備條件；采用典型含硫化合物二苯并噻吩(DBT)和4,6二甲基二苯并噻吩(4,6-DMDBT),考察了金屬磷化物的加氫脫硫催化反應(yīng)性能；采用XRD、CO化學(xué)吸附、TPR、HRTEM、SEM、ICP-AES等對金屬磷化物的結(jié)構(gòu)進(jìn)行了表征,初步研究了氫等離子體還原法制備過渡金屬磷化物的反應(yīng)機理。 論文系統(tǒng)考察了電壓、放電時間、金屬與磷的原子比(M/P)及加入貴金屬對體相Ni2P, CoP, MoP和WP制備的影響。結(jié)果表明,提高電壓和增加還原時間有利于提高所制備的金屬磷化物的晶化程度；當(dāng)金屬磷化物存在一種晶型(如WP和MoP)時,氧化物前體中M/P影響其晶化程度；當(dāng)存在多種晶型時,M/P比決定了金屬磷化物的晶體結(jié)構(gòu)；PR法可以按化學(xué)計量比制備金屬磷化物,而不需要在其前體引入過量的磷；少量引入貴金屬(如Ru)可進(jìn)一步緩和制備條件；采用PR法可制備磷化鎵(GaP)、磷化銦(InP)、磷化鐵(Fe2P)等重要半導(dǎo)體材料。 采用PR法和傳統(tǒng)程序升溫還原法制備了體相Ni2P、CoP、MoP和WP,比較了不同方法制備的體相磷化物在DBT加氫脫硫反應(yīng)中的催化性能；研究了制備條件和鈍化方法對磷化物晶化度和加氫脫硫催化反應(yīng)的影響規(guī)律。發(fā)現(xiàn)PR法制備的催化劑比傳統(tǒng)程序升溫法制備的活性高；PR法制備的體相磷化物活性順序為CoPNi2PMoP≈WP。 研究發(fā)現(xiàn)CoP在四種金屬磷化物中制備條件最為苛刻,且易于形成加氫脫硫活性很低的Co2P相,因而采用傳統(tǒng)程序升溫還原法制備的CoP催化劑在加氫脫硫反應(yīng)中表現(xiàn)出最低的活性。當(dāng)在氧化物前體中引入少量Ru時,可以在較溫和條件下制備出高結(jié)晶度、高活性CoP催化劑。反應(yīng)評價結(jié)果表明,Ru的引入主要促進(jìn)了CoP的形成,改善了晶粒的分散,但沒有明顯改變催化反應(yīng)過程和活性中心本質(zhì)。 用PR法制備了MCM-41擔(dān)載的WP、MoP和Ni2P催化劑,以DBT和4,6-DMDBT的十氫萘溶液為模擬油考察了其加氫脫硫反應(yīng)性能。對混合物料HDS活性順序為：WPMoPNi2P, WP和MoP以加氫脫硫路徑為主,Ni2P以直接脫硫路徑為主。若將WP/MCM-41與Ni2P/MCM-41機械混合,則可以同時高效脫除DBT和4,6-DMDBT。此外,比較了不同方法制備的Ni-W-P在加氫脫硫反應(yīng)中的催化活性,其活性順序順序為：先硫化后還原法PR法先混合后還原法(MR)共浸漬法。共浸漬法制備的Ni-W-P活性低的主要原因是有雜晶生成。
[Abstract]:As a new type of semiconductor materials, transition metal phosphide can be widely used in the fields of photoelectric, magnetic, catalysis and so on. Metal phosphide is often prepared by programmed temperature reduction as a catalyst, but this method has high temperature, the phosphorus species is easy to lose, and the high temperature preparation is easy to lead to the sintering of the catalyst particles. In this paper, the hydrogen plasma reduction method (PR) is used in this paper. A series of transition metal phosphide was prepared, and the preparation conditions of nickel phosphide (Ni2P), phosphide (CoP), molybdenum phosphide (MoP) and tungsten phosphide (WP) were prepared. The catalytic properties of the hydrodesulfurization of metal phosphide were investigated by using the typical sulfur compounds two benzo thiophene (DBT) and 4,6 two methyl two benzo thiophene (4,6-DMDBT). XRD, CO was used. The structure of metal phosphide was characterized by chemical adsorption, TPR, HRTEM, SEM, ICP-AES and so on. The reaction mechanism of the transition metal phosphide prepared by the hydrogen plasma reduction method was preliminarily studied.
The effects of voltage, discharge time, atomic ratio of metal to phosphorus (M/P) and the addition of precious metals to the bulk phase Ni2P, CoP, MoP and WP are investigated. The results show that increasing the voltage and increasing the reduction time are beneficial to the crystallization of the metal phosphide. When a crystalline form of metal phosphide (such as WP and MoP), the oxidation of metal phosphide is oxidized. M/P affects the crystallization degree of the precursors; when there are various crystalline forms, the M/P ratio determines the crystal structure of the metal phosphide; the PR method can prepare the metal phosphide according to the stoichiometric ratio, without the introduction of the excess phosphorus in its precursor; a small amount of precious metals (such as Ru) can be used to prepare the preparation conditions, and the PR method can be used to prepare the gallium phosphide. GaP), indium phosphide (InP), iron phosphide (Fe2P) and other important semiconductor materials.
The bulk phase Ni2P, CoP, MoP and WP were prepared by the PR method and the traditional temperature programmed reduction method. The catalytic properties of the bulk phase phosphide prepared by different methods in the DBT hydrodesulfurization reaction were compared. The effects of preparation conditions and passivation methods on the crystallinity of phosphide and the catalytic reaction of hydrodesulfurization were studied. It was found that the catalyst prepared by the PR method was specific to the catalyst. The activity prepared by the programmed temperature method is high, and the active phase of the phosphor prepared by PR is CoPNi2PMoP WP..
It is found that the preparation conditions of CoP in four kinds of metal phosphide are most harsh and easy to form Co2P phase with low hydrodesulfurization activity. Therefore, the CoP catalyst prepared by the traditional temperature programmed reduction method has the lowest activity in the hydrodesulfurization reaction. When a small amount of Ru is introduced in the oxide precursor, it can be made under mild conditions. The high crystallinity and high active CoP catalyst were prepared. The results of the reaction evaluation showed that the introduction of Ru mainly promoted the formation of CoP and improved the dispersion of the grain, but did not change the catalytic reaction process and the essence of the active center.
The MCM-41 supported WP, MoP and Ni2P catalysts were prepared by PR method. The hydrodesulfurization reaction properties of the ten hydrogen naphthalene solution of DBT and 4,6-DMDBT were investigated. The order of HDS activity of the mixed materials was WPMoPNi2P, WP and MoP were mainly hydrodesulfurization path, and the Ni2P was mainly desulphurizing path. DBT and 4,6-DMDBT. can be effectively removed at the same time, and the catalytic activity of Ni-W-P in the hydrodesulfurization reaction prepared by different methods is compared. The order of the activity sequence is: first after the vulcanization and the reduction method, the PR method is first mixed with the reduction method (MR) Co impregnation. The main reason for the low viability of Ni-W-P prepared by CO impregnation is the formation of the hetero crystal.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2011
【分類號】：O643.36

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 熊軼超;納米二氧化鈦改性及其可見光光催化性能研究[D];大連理工大學(xué);2012年

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本文編號：2019447