表面修饰二维纳米材料与电子结构调制
发布时间：2018-11-12 09:18
【摘要】：二维无机纳米材料,由于其超薄的结构特征和量子限域效应,能够表现出一个维度受限条件下新奇的电子与自旋结构,为广泛应用如新型的电子器件,磁性材料,高效的催化材料,以及能源存储材料等带来了新的材料平台。随着对二维无机纳米材料研究的不断深入,科学家们逐渐地由注重合成转向探究和调控二维无机纳米材料的本征物理性质。相较于其三维块体材料,二维超薄纳米材料暴露出大量表面原子,使得其表面变得尤为重要。同时,量子限域效应使得二维纳米材料的电子间有较强的相互作用,自旋、电荷、轨道、晶格间的耦合也更加强烈,这使得表面修饰二维纳米材料能够有效改变其局域电子的整体电荷和自旋态,有望实现对其电子性质、磁学性质等本征属性的有效调节,为设计和开发新型无机二维纳米材料带来新思路。本论文以二维纳米材料的电子结构与其本征性质为切入点,以无机二维纳米材料为研究对象,依据其超薄结构的表面化学反应性特点,通过表面化学修饰策略对二维纳米材料的电子结构和自旋结构进行调制,以来实现本征物理性质调控。我们设计和开展了包括表面化学吸附,表面氢修饰和表面硫修饰等有效表面修饰手段,对二维纳米材料的本征物理性质进行了有效调制,构建了新型二维纳米材料结构,获得了二维纳米材料磁电输运行为调制,并应用于电催化领域。本论文具体的内容包括以下几个方面:1、本工作中,我们通过表面修饰策略在二维二硒化铌纳米片表面吸附肼分子,实现了将本征铁磁引入超导NbSe2二维结构骨架中,从而获得了超导与铁磁共存于单一物相的二维纳米材料。强极性和还原性的肼分子吸附在NbSe-2表面,既确保了 NbSe2的原始骨架结构的完整性,又诱发了 NbSe2的局域结构畸变,促使Nb-Se键的伸长,导致了 Nb-Se原子间共价作用力的削弱和增强了四价Nb离子的离子性,最终成功地向二二维超导NbSe-2材料中引入了铁磁性。在单一的二维纳米材料中实现的超导与铁磁共存引发了耦合效应,如负磁阻效应及近藤效应。本工作提出了一种在二维材料中引入铁磁性的有效策略。2、本工作中,我们通过有效的化学剥离方法获得了表面氢修饰的二硫化钛超薄纳米片,表面修饰的氢原子向二硫化钛平面导电骨架注入电子增加了载流子浓度,从而增强了 S-Ti-S骨架里的电子关联作用并成功调控了二硫化钛纳米片的平面导电性。氢化二硫化钛纳米片的导电性随着表面氢含量的增加而提升,由超薄表面氢修饰的二硫化钛纳米片组装的薄膜的电导率在室温下能够达到6.76×104 S/m。与此同时,表面氢修饰的二硫化钛超薄纳米片组装的薄膜在机械性能和耐高压性方面性能优异。我们以PDMS(聚二甲基硅氧烷)为印章,可以将薄膜成功的转移到任意基底上,而且保证薄膜的导电性在转移过程中不会受到破坏。本研究表明通过这种表面修饰二维纳米材料以加强强电子关联体系,进而来实现对二维纳米材料电学性质的调控是一种行之有效的手段。3、本工作中,通过表面硫修饰成功地调控了 Ni(OH)2纳米片的电子结构,我们获得了金属态的二维过渡金属氢氧化物。结合局域结构表征和反应热力学计算,我们发现Ni(OH)2纳米片的结构骨架维持不变,其表面的部分氧原子被硫取代。表面硫修饰能够实现金属态Ni(OH)2纳米片的活性位点和电子态的双重调制。金属态Ni(OH)2纳米片在室温下展现出优异的导电性(3.19× 103S/m)以保证有效的电子传输;纳米片表面的金属Ni离子周围电子密度增加从而加速了 CO2从催化中心的脱附速率,进而暴露出更多的催化位点。相对于原始的Ni(OH)2纳米片,金属态Ni(OH)2纳米片的催化尿素氧化(UOR)过程中有更大的催化电流,更小的起始电位和更高的稳定性。本工作提出了一种调控二维过渡金属氢氧化物的电子. 结构的有效方法。
[Abstract]:The two-dimensional inorganic nano-material can exhibit a novel electron and spin structure under the condition of limited dimension due to its ultra-thin structural characteristics and quantum confinement effect, and is a novel electronic device, a magnetic material and a high-efficiency catalytic material. and the energy storage material and the like. With the development of the study of two-dimensional inorganic nano-materials, the scientists gradually study and control the intrinsic physical properties of the two-dimensional inorganic nano-materials. Compared with the three-dimensional block material, the two-dimensional ultra-thin nano-material exposes a large number of surface atoms, so that the surface thereof becomes particularly important. meanwhile, the quantum-limited domain effect makes the electrons of the two-dimensional nano material have strong interaction, and the coupling between the spin, the charge, the track and the lattice is also stronger, so that the surface-modified two-dimensional nano-material can effectively change the whole charge and the spin state of the local electrons, It is expected to realize the effective regulation of its electronic properties, magnetic properties and other intrinsic properties, and to bring a new thought to the design and development of new inorganic two-dimensional nano-materials. Taking the electronic structure of two-dimensional nano-material and its intrinsic property as the starting point, the paper takes the inorganic two-dimensional nano-material as the research object, and according to the surface chemical reactivity of the ultra-thin structure, The surface chemical modification strategy is used to modulate the electronic structure and the spin structure of the two-dimensional nano-material. We designed and carried out effective surface modification methods including surface chemical adsorption, surface hydrogen modification and surface sulfur modification. The intrinsic physical properties of two-dimensional nano-materials were effectively modulated, and a new two-dimensional nano-material structure was constructed. and the two-dimensional nano material magnetoelectric transport behavior modulation is obtained, and the two-dimensional nano material magnetoelectric transport behavior modulation is applied to the field of electrocatalysis. The specific content of the thesis consists of the following aspects: 1. In the work, the molecule is adsorbed on the surface of the two-dimensional diselenide nano-sheet by a surface modification strategy, and the intrinsic ferromagnetic is introduced into the superconducting NbSe2 two-dimensional structure framework, so as to obtain the two-dimensional nano material of the superconducting and ferromagnetic co-existence in a single phase. the strong polarity and the reducing molecule are adsorbed on the surface of the NbSe-2, so that the integrity of the original framework structure of the NbSe2 is ensured, the local structural distortion of the NbSe2 is induced, the elongation of the Nb-Se bond is promoted, the covalent interaction between the Nb-Se atoms is weakened, and the ionic property of the tetravalent Nb ions is enhanced, and finally, the ferromagnetism is successfully introduced into the two-dimensional superconducting NbSe-2 material. The co-existence of superconductivity and ferromagnetic in a single two-dimensional nano-material induces a coupling effect, such as a negative magnetic resistance effect and a rattan effect. in this work, an effective strategy of ferromagnetism is introduced in two-dimensional material. the surface-modified hydrogen atom injected electrons into the two-sulfide-titanium planar conductive framework to increase the carrier concentration, thereby enhancing the electron correlation function in the S-Ti-S framework and successfully controlling the planar conductivity of the titanium disulfide nano-sheet. The conductivity of the hydrogenated titanium disulfide nanosheet increases with the increase of the surface hydrogen content, and the conductivity of the thin film assembled by the ultra-thin surface hydrogen modified titanium disulfide nano-sheet can reach 6.76-104S/ m at room temperature. At the same time, the film assembled with the surface hydrogen-modified titanium disulfide ultrathin nanosheet has excellent performance in terms of mechanical properties and high-pressure resistance. PDMS (polydimethylsiloxane) is used as a seal, so that the film can be successfully transferred to any substrate, and the conductivity of the film is ensured not to be damaged during the transfer process. in that work, the electronic structure of the Ni (OH) 2 nanosheet was successfully control by surface-sulfur modification, We have obtained a two-dimensional transition metal hydroxide in the form of a metal. The structural framework of the Ni (OH) 2 nanosheet was found to be unchanged in combination with the local structure characterization and the reaction thermodynamic calculation. The partial oxygen atoms of the surface of the Ni (OH) 2 nanosheets were replaced with sulfur. The surface-sulfur modification can realize the double modulation of the active site and the electronic state of the metal-state Ni (OH) 2 nanosheet. The metal-state Ni (OH) 2 nanosheet exhibits excellent electrical conductivity at room temperature (3.19-103S/ m) to ensure effective electron transport; the electron density around the metal Ni ions on the surface of the nanosheet increases so as to accelerate the desorption rate of CO2 from the catalytic center, thereby exposing more catalytic sites. With respect to the original Ni (OH) 2 nanosheet, the catalytic urea oxidation (UOR) of the metal-state Ni (OH) 2 nanosheet has a greater catalytic current, a smaller starting potential and higher stability. The invention provides an electron for regulating the two-dimensional transition metal hydroxide. the effective method of the structure.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1
本文编号：2326697
[Abstract]:The two-dimensional inorganic nano-material can exhibit a novel electron and spin structure under the condition of limited dimension due to its ultra-thin structural characteristics and quantum confinement effect, and is a novel electronic device, a magnetic material and a high-efficiency catalytic material. and the energy storage material and the like. With the development of the study of two-dimensional inorganic nano-materials, the scientists gradually study and control the intrinsic physical properties of the two-dimensional inorganic nano-materials. Compared with the three-dimensional block material, the two-dimensional ultra-thin nano-material exposes a large number of surface atoms, so that the surface thereof becomes particularly important. meanwhile, the quantum-limited domain effect makes the electrons of the two-dimensional nano material have strong interaction, and the coupling between the spin, the charge, the track and the lattice is also stronger, so that the surface-modified two-dimensional nano-material can effectively change the whole charge and the spin state of the local electrons, It is expected to realize the effective regulation of its electronic properties, magnetic properties and other intrinsic properties, and to bring a new thought to the design and development of new inorganic two-dimensional nano-materials. Taking the electronic structure of two-dimensional nano-material and its intrinsic property as the starting point, the paper takes the inorganic two-dimensional nano-material as the research object, and according to the surface chemical reactivity of the ultra-thin structure, The surface chemical modification strategy is used to modulate the electronic structure and the spin structure of the two-dimensional nano-material. We designed and carried out effective surface modification methods including surface chemical adsorption, surface hydrogen modification and surface sulfur modification. The intrinsic physical properties of two-dimensional nano-materials were effectively modulated, and a new two-dimensional nano-material structure was constructed. and the two-dimensional nano material magnetoelectric transport behavior modulation is obtained, and the two-dimensional nano material magnetoelectric transport behavior modulation is applied to the field of electrocatalysis. The specific content of the thesis consists of the following aspects: 1. In the work, the molecule is adsorbed on the surface of the two-dimensional diselenide nano-sheet by a surface modification strategy, and the intrinsic ferromagnetic is introduced into the superconducting NbSe2 two-dimensional structure framework, so as to obtain the two-dimensional nano material of the superconducting and ferromagnetic co-existence in a single phase. the strong polarity and the reducing molecule are adsorbed on the surface of the NbSe-2, so that the integrity of the original framework structure of the NbSe2 is ensured, the local structural distortion of the NbSe2 is induced, the elongation of the Nb-Se bond is promoted, the covalent interaction between the Nb-Se atoms is weakened, and the ionic property of the tetravalent Nb ions is enhanced, and finally, the ferromagnetism is successfully introduced into the two-dimensional superconducting NbSe-2 material. The co-existence of superconductivity and ferromagnetic in a single two-dimensional nano-material induces a coupling effect, such as a negative magnetic resistance effect and a rattan effect. in this work, an effective strategy of ferromagnetism is introduced in two-dimensional material. the surface-modified hydrogen atom injected electrons into the two-sulfide-titanium planar conductive framework to increase the carrier concentration, thereby enhancing the electron correlation function in the S-Ti-S framework and successfully controlling the planar conductivity of the titanium disulfide nano-sheet. The conductivity of the hydrogenated titanium disulfide nanosheet increases with the increase of the surface hydrogen content, and the conductivity of the thin film assembled by the ultra-thin surface hydrogen modified titanium disulfide nano-sheet can reach 6.76-104S/ m at room temperature. At the same time, the film assembled with the surface hydrogen-modified titanium disulfide ultrathin nanosheet has excellent performance in terms of mechanical properties and high-pressure resistance. PDMS (polydimethylsiloxane) is used as a seal, so that the film can be successfully transferred to any substrate, and the conductivity of the film is ensured not to be damaged during the transfer process. in that work, the electronic structure of the Ni (OH) 2 nanosheet was successfully control by surface-sulfur modification, We have obtained a two-dimensional transition metal hydroxide in the form of a metal. The structural framework of the Ni (OH) 2 nanosheet was found to be unchanged in combination with the local structure characterization and the reaction thermodynamic calculation. The partial oxygen atoms of the surface of the Ni (OH) 2 nanosheets were replaced with sulfur. The surface-sulfur modification can realize the double modulation of the active site and the electronic state of the metal-state Ni (OH) 2 nanosheet. The metal-state Ni (OH) 2 nanosheet exhibits excellent electrical conductivity at room temperature (3.19-103S/ m) to ensure effective electron transport; the electron density around the metal Ni ions on the surface of the nanosheet increases so as to accelerate the desorption rate of CO2 from the catalytic center, thereby exposing more catalytic sites. With respect to the original Ni (OH) 2 nanosheet, the catalytic urea oxidation (UOR) of the metal-state Ni (OH) 2 nanosheet has a greater catalytic current, a smaller starting potential and higher stability. The invention provides an electron for regulating the two-dimensional transition metal hydroxide. the effective method of the structure.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB383.1
【参考文献】
相关期刊论文 前1条
1 朱小姣;郭宇桥;吴长征;;表面化学修饰调控无机二维纳米材料的磁性及其应用[J];科学通报;2017年20期
，本文编号：2326697
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