【作者】 李海红；

【导师】 杜恣毅； 曹黎明；

【作者基本信息】 江西师范大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 析氢反应（HER）是电化学水分解的一个组成部分,研发高效的HER催化剂非常关键。钌（Ru）有着和Pt相似的活性,当前,合成低金属含量的高效Ru基催化剂是研究的热点。团簇级金属催化剂不仅拥有高的金属利用率,而且能够暴露更多的活性位点,具有优异的催化活性。然而,当前高效团簇级Ru催化剂的合成依旧是一大挑战。多孔有机聚合物（POP）具有稳定的孔结构,高比表面积、易修饰等突出优点,其配位基团/原子在热解时能限制金属的迁移和团聚,从而限域合成团簇级纳米结构。其次POP含有丰富的非金属杂原子,在热解过程中可以被均匀地掺入到碳层或Ru中,可以进一步提升Ru基亚纳米簇的催化活性;最后POP在热解中派生的碳层可以保护Ru基亚纳米簇,避免其在催化过程中团聚。据此,本论文采用硒基POP配位限域-热解方法设计合成了团簇级Ru Se催化剂,探究了样品表面活性结构的调控,同时研究团簇级Ru Se亚催化剂与HER性能间的构效联系。主要内容为:采用硒基POP配位限域-热解策略合成了平均粒径为1.0 nm的团簇级Ru Se。POP中的Se原子不仅有益于热解合成过程中减小纳米粒子尺寸,而且可以被掺入Ru的晶格中并调节活性位点电子结构,从而显著提升催化剂的电催化活性。合成的Ru Se@NC@CNT表现出优异的碱性HER活性,在玻碳电极上,达到10 m A·cm^-2和100m A·cm^-2的电流密度仅需8.6±0.4 m V和46.2±1.0 m V的过电位;在碳布（CC）上,在电流密度为1 A·cm^-2和2 A·cm^-2时,过电位仅为63.4±0.9 m V和107.9±1.6 m V;在过电位为100 m V时,转化频率（TOF）为7.32 s^-1。Ru Se@NC@CNT也具有良好的稳定性,在碳布（CC）上,循环伏安法（CV）测试15000次后,其LSV极化曲线未见明显变化,在100 m A·cm^-2的恒电流密度下电解50 h后电位几乎保持不变。这一工作为团簇级Ru基催化剂的精准合成以及高性能HER电催化剂的设计提供了新的策略。更多还原

【Abstract】 Hydrogen evolution reaction（HER）is an integral part of electrochemical water splitting,and it is crucial to develop efficient HER catalysts.Ruthenium（Ru）has similar activity to Pt,and currently,the synthesis of efficient Ru-based catalysts with low metal content is a hot research topic.Cluster-level metal catalysts not only possess high metal utilization,but also can expose more active sites and have excellent catalytic activity.However,the synthesis of efficient cluster-level Ru catalysts remains a major challenge at present.Porous organic polymers（POP）have outstanding advantages such as stable pore structure,high specific surface area and easy modification,and their ligand groups/atoms can restrict the migration and agglomeration of metals during pyrolysis,thus limiting the synthesis of cluster-level nanostructures.Secondly,POP is rich in non-metallic heteroatoms,which can be uniformly doped into the carbon layer or Ru during pyrolysis,which can further enhance the catalytic activity of Ru-based nanoclusters;finally,the carbon layer derived from POP in pyrolysis can protect Ru-based nanoclusters from agglomeration during the catalytic process.Accordingly,in this thesis,a cluster-level Ru Se catalyst was designed and synthesized using a selenium-based POP ligand-limited-pyrolysis method to explore the modulation of the active structure on the surface of the sample,and to investigate the conformational link between the cluster-level Ru Se sub-catalyst and HER performance.The main contents are:Cluster-level Ru Se with an average particle size of 1.0 nm was synthesized using a selenium-based POP confinement-pyrolysis strategy.Se atoms in POP not only benefit from the reduction of nanoparticle size during the pyrolysis synthesis,but also can be incorporated into the lattice of Ru and modulate the electronic structure of the active site,thus significantly enhancing the electrocatalytic activity of the catalyst.The synthesized Ru Se@NC@CNT exhibited excellent basic HER activity,only requiring the overpotentials of 8.6±0.4 and 46.2±1.0 m V to reach the current densities of 10 and 100 m A·cm^-2 on glassy carbon electrodes;requiring the overpotentials of 63.4±0.9 and 107.9±1.6 m V at current densities of 1 A·cm^-2 and2 A·cm^-2 on carbon cloth（CC）;and the turnover frequency（TOF）is 7.32 s^-1 at an overpotential of 100 m V.Ru Se@NC@CNT also has good stability,with no significant change in its LSV polarization curve after 15,000 cycles of cyclic voltammetry（CV）tests on carbon cloth（CC）,and the potential remains almost constant after 50 h of electrolysis at a constant current density of 100 m A·cm^-2.This work provides a new strategy for the precise synthesis of cluster-level Ru-based catalysts and the design of HER electrocatalysts.更多还原