【作者】 王磊；

【导师】 张文林；

【作者基本信息】 河北工业大学 ， 化学工程与技术， 2022， 硕士

【摘要】 为了解决化石能源危机和环境污染问题,人们开始探寻新型清洁可再生能源,其中以燃料电池和金属-空气电池研究的最为广泛。在这些装置中均涉及到了氧还原反应(ORR)与析氧反应(OER),这是能源转化装置阴极上的核心反应,但ORR动力学缓慢且需要使用高效催化剂。商业上广泛使用Pt/C催化剂,由于成本高和稳定性差等缺点,导致其无法广泛商用。因此开发用于替代Pt/C的新型高效稳定又廉价易得的催化剂成为当下重要的研究方向。本文使用吡咯单体自发聚合和四磺酸钠酞菁铜一体式掺杂的合成方法,设计并成功合成了两类杂原子掺杂的铜单原子催化剂,主要内容如下:(1)二价铜离子引发吡咯单体聚合,将铜原子锚定在聚吡咯水凝胶中,形成了铜氮碳前驱体;将混合完全的前驱体与植酸一同加入管式炉中热解,得到了杂原子氮磷共掺杂的铜单原子催化剂。通过调节热解温度,得到Cu-N/P-C-X系列催化剂,结合多种实验表征分析催化剂的活性位点,并探究温度对催化剂的元素含量和N元素种类的影响。其中,Cu-N/P-C-700拥有最佳的ORR活性,其半波电位达到了0.87 V(vs.RHE),优于商业Pt/C和Cu-N-C-700催化剂。另外,Cu-N/P-C-700在ORR中的电化学稳定性和在锌-空气电池中的实际性能也显著优于Pt/C,表明Cu-N/P-C-700是一种具有良好电化学性能的双功能催化剂。使用密度泛函理论计算证明了杂原子磷的引入对CuN-C-700催化剂具有明显的结构改善和电化学性能提升作用。(2)使用一种金属沸石咪唑酯结构作为基础框架,将四磺酸钠酞菁铜作为铜源和硫源掺入,调节四磺酸钠酞菁铜与金属锌盐的掺杂比例,经过高温热解成功制得了Cu NSC-Ts-X系列催化剂。同时使用另外几种铜源与硫源制备了Cu NSC-Lcy-X和Cu NSC-Pc S-X等催化剂。利用XRD,TEM和XPS等多种表征方法,探究和验证了催化剂中的活性位点。其中,Cu NSC-Ts-40拥有最佳的ORR性能,Cu NSC-Ts-40的起始电位和半波电位达到了1.00 V和0.87 V,在锌-空气电池测试中,Cu NSC-Ts-40也表现出良好的电化学性能。使用密度泛函理论计算证明了杂原子硫的引入对催化剂的ORR性能具有提升作用。更多还原

【Abstract】 In order to solve the fossil energy crisis and environmental pollution problems,great attentions have been attracted to develop clean and renewable energy sources,among which fuel cells and metal-air cells are the most widely studied.In these devices,oxygen reduction reactions(ORR)are involved,which is the core reactions on the cathode of energy conversion devices.Pt-based materialsare widely used as commercial ORR catalysts,but their high cost and poor stability have prevented their widespread commercial application.Therefore,the development of new efficient,stable and inexpensive catalysts to replace Pt/C has become one of the important research directions nowadays.In this paper,two types of heteroatomdoped copper monatomic catalysts were designed and successfully synthesized using the synthesis method of spontaneous polymerization of pyrrole monomer and one-piece doping of copper tetrasulfonate phthalocyanine.The main elements are as follows.(1)Copper ions triggered the polymerization of pyrrole monomers to form a coppernitrogen-carbon precursor.Then,the completely mixed precursors were added to the tube furnace together with phytic acid for pyrolysis to obtain heteroatomic nitrogen-phosphorus co-doped copper monatomic catalysts.The temperature of pyrolysis was varied to obtain CuN/P-C-X series catalysts.A variety of experimental characterizations were used to analyze the active sites of the catalysts and to investigate the effect of temperature on the elemental content of the catalysts as well as the N elemental species.Cu-N/P-C-700 has the best ORR activity with a half-wave potential of 0.87 V(vs.RHE),which is superior to commercial Pt/C and Cu-N-C-700 catalysts.The electrochemical stability of Cu-N/P-C-700 in ORR and the practical application performance in Zn-Air batteries are also significantly better than Pt/C,indicating that Cu-N/P-C-700 is a bifunctional catalyst with good electrochemical performance.Density functional theory calculations demonstrate that the introduction of heteroatomic phosphorus has a significant structural improvement and electrochemical performance enhancement on Cu-N-C-700 catalysts.(2)Copper tetrasulfonate phthalocyanine as a copper and sulfur source was doped into a metal zeolite imidazole ester structure,and then the doping ratio of copper tetrasulfonate phthalocyanine to metal zinc salt was changed.Finally,the Cu NSC-Ts-X catalysts were produced by pyrolysis at high temperature.Cu NSC-Lcy-X and Cu NSC-Pc S-X catalysts were prepared using additional copper sources and sulfur sources.The active sites in the catalyst were explored and verified using various characterization methods such as XRD,TEM and XPS.Cu NSC-Ts-40 possessed the best ORR performance,with Cu NSC-Ts-40 reaching an onset potential and half-wave potential of 1.00 V and 0.87 V.Cu NSC-Ts-40 also exhibited good electrochemical performance in Zn-Air batteries tests.The introduction of heteroatomic sulfur has been demonstrated to have an enhancing effect on the ORR performance using density functional theory calculations.更多还原