【作者】 张华；

【导师】 熊胜林； 奚宝娟；

【作者基本信息】 山东大学 ， 无机化学， 2021， 硕士

【摘要】 人们对清洁、高效和可再生能源以有效取代化石燃料以及为可持续的未来与环境和能源短缺作斗争的关注相当大。在此背景下,氢气是一种清洁、可再生、节能、未来潜力无限的燃料,它可以通过电催化分解地球上丰富的水资源产生大量的能量。电化学全解水过程产生的氢气和氧气可以为燃料电池提供原料,实现能源的可持续利用。因此,全解水两个半反应的效率对电化学全解水的整体性能起着重要作用。对于全解水的这两个半反应Pt基催化剂具有优异的析氢性能,Ru或Ir的氧化物具有优异的析氧性能,然而贵金属成本高这一普遍的缺点限制了它们的商业应用,因此,开发高效、稳定的电催化剂降低反应的能垒提高催化剂效率是电催化领域的要求。过渡金属基电催化剂因资源丰富、组成多样、催化性能与贵金属相当而在近年来吸引了大量目光。在这些过渡金属中,镍因其具有独特的电子特性和预期的协同效应而显著改变材料的表面性质有利于电催化作用,已成为最有希望的成分之一。针对单一镍基的导电性差、活性差的问题,本文利用掺杂和构建异质结构的策略设计钼掺杂硫化镍复合氢氧化镍(Mo-NiS/Ni(OH)2)全解水双功能催化剂和竹节状碳纳米管包覆磷化镍纳米颗粒析氢催化剂,主要内容如下:(1)通过简单的的溶剂热和原位生长方法合成了稳定的异质结构Mo-NiS/Ni(OH)2作为电催化全解水双功能催化剂。基于异质金属原子的掺杂和界面相互作用,异质结构的电导率得到了改善,电荷在界面间的转移动力学得到了促进,Mo-NiS/Ni(OH)2在1M KOH溶液中显示了优异的HER和OER活性,在10mAcm-2的电流密度下,过电势仅为74 mV和186 mV,塔菲尔斜率分别为90 mV dec-2和23 mV dec-2。Mo-NiS/Ni(OH)2作为双功能催化剂分解水,仅需1.5 V下就能达到10 mA cm-2的电流密度,并在25 mA cm-2下表现出100小时的长期稳定性,电流密度仅有5%的损失。(2)通过自模板-自催化热解次磷酸钠预处理过的g-C3N4纳米片和氯化镍的混合材料制备了尖端包覆NiP纳米颗粒的竹节状碳纳米管(NiP-CNTs),碳纳米管的引入不仅可以提高NiP纳米颗粒的导电性,而且碳纳米管能够使被包覆NiP纳米颗粒免受强碱溶液的腐蚀,这种复合材料基于碳纳米管和磷化镍颗粒的相互作用提高电子在两者之间的转移,NiP-CNTs在碱性溶液中显示出良好的HER性能,并且在25 mA cm-2下表现出15小时的长期稳定性。更多还原

【Abstract】 Consierable attention has been paid to clean,efficient and renewable sources of energy to effectively replace fossil fuels and to combat environmental and energy shortages for a sustainable future.In this context,hydrogen is a clean,renewable,energy-efficient and potentially future fuel that can generate large amounts of energy through electrocatalytic decomposition of Earth’s abundant water resources.Electrochemical total hydrolysis process includes two half reactions:cathode hydrogen evolution reaction(HER)and anode oxygen evolution reaction(OER).These two half reactions play an important role in the overall performance of electrochemical total hydrolysis of water.For HER and OER,Pt-based catalysts and oxides of Ru or Ir are the best electrocatalysts respectively.However,the high cost and low abundance greatly limit their commercial applications.Therefore,the development of efficient and stable electrocatalysts is a requirement in the field of electrocatalysis.Transition metal-based electrocatalysts have attracted extensive attention because of their abundant resources,low cost and catalytic performance comparable to precious metals.Aiming at the problems of poor conductivity and poor activity of single nickel base,this paper designed a molybdenum doped nickel sulfide composite nickel hydroxide(Mo-Nis/Ni(OH)2)fully hydrolyzed bifunctional catalyst and a bamboo-like carbon nanotube coated nickel phosphate nanoparticle hydrogen evolution catalyst by using the strategy of doping and heterostructure construction.The main contents are as follows:(1)The stable heterostructure Mo-NiS/Ni(OH)2 was synthesized by solvothermal and in situ growth methods as a bifunctional catalyst for electrocatalytic overall water splitting.Mo-NiS/Ni(OH)2 shows excellent HER and OER activities in alkaline solution.At the current density of 10 mA cm-2,the electroconductivity of the heterostructure is improved and the charge transfer kinetics between the interfaces also is promoted.The overpotential is only 74 mV and 186 mV,and the Tafel slope is 90 mV dec-2 and 23 mV dec-2,respectively.Mo-NiS/Ni(OH)2 was used as cathode and anode respectively to construct the total hydrolyzing device.The current density of 10 mA cm-2 could be reached at 1.5V,and it showed long-term stability for 100 hours at 25 mA cm-2,with only 5%loss of current density.(2)NiP nanoparticle coated bamboo-shaped carbon nanotubes(NiP-CNTs)were prepared by a mixture of g-C3N4 nanosheets pretreated by self-template-autocatalytic pyrolysis of sodium hyphophosphate and nickel chloride.The introduction of carbon nanotubes not only improve the electrical conductivity of NiP nanoparticles,but also improve the performance of nanotubes.In addition,NiP nanoparticles were protected from corrosion by strong alkali solution by CNTs.This composite material was based on the interaction between CNTs and nickel phosphide particles to improve electron transfer between them.the NiP-CNTs in alkaline solution shows good performance at 10 mA cm-2 current density,the overpotential is only 82 mV,tafel slope is 91 mV dec-1,under 25 mA cm-2 it showed the long-term stability of the 15 h.更多还原