铜基催化剂的制备及电催化析氧性能研究

发布时间：2018-04-20 07:25

  本文选题：析氧反应 + 铜基催化剂　； 参考：《西南石油大学》2017年硕士论文

【摘要】：在高效的水分解体系中,具备高活性、出色稳定性以及低过电位的催化剂是必不可少的。从贵金属到过渡金属氧化物,虽然不计其数的均相与异相催化剂已经被尝试用于减小析氧半反应(OER)较高的过电位,但在探寻高效、低廉的OER催化剂的这条道路上依然充满着未知与挑战。铜是一种非常廉价的金属元素,其各种形式的化合物在化学、生物等领域显示出良好的催化性能。本论文从元素掺杂与表面修饰两方面着手进行铜基催化剂的制备,并研究其在OER中的电催化性能。论文利用阳极沉积法成功制得了CuNiOx与CuCoOx薄膜。利用SEM、XRD对催化剂形貌、结构进行表征,证明该薄膜为非晶结构。电化学性能测试结果表明,在不同体系中CuNiOx与 CuCoOx样品的OER催化活性均优于CuO样品,通过对沉积时间、沉积方式、元素比例以及体系pH的优化,得到在碳酸体系中样品CuNiOx(4:1)性能最优,其OER起始过电位为320 mV,在电流密度为5 mA/cm2下,可持续催化10 h以上。XPS结果显示,二元氧化物样品中氧缺陷含量成倍增加,该基团可加快电子向吸附物质的传递速率进而提升OER催化活性。同时,论文还利用化学刻蚀法成功制备了原位生长的自支撑CuO/CF(泡沫铜)电极。经SEM、XRD测试表明不同煅烧温度下的催化剂形貌以及晶体结构存在明显差异。电化学性能测试结果表明,煅烧温度为500 ℃时的CuO/CF显示出最好的OER性能,在1.8 V(vs.RHE)电位下最大电流密度达到90 mA/cm2,优于目前文献报道的结果,其卓越的OER催化性能主要归功于极高的表面积,电催化活性面积(ECSA)测试结果显示,处理后的催化剂表面积增加了约3倍。除此之外,该方法原位生成的CuO膜对CF骨架形成保护,有效抑制了 CF在高电位下的降解,增强了催化剂的使用寿命。
[Abstract]:In an efficient water decomposition system, catalysts with high activity, excellent stability and low overpotential are essential. From precious metals to transition metal oxides, although countless homogeneous and heterogeneous catalysts have been tried to reduce the high overpotential of oxygen evolution half-reaction, they are looking for high efficiency. The path of cheap OER catalyst is still full of unknown and challenges. Copper is a very cheap metal element, its various forms of compounds in chemical, biological and other fields show good catalytic performance. In this paper, the preparation of Cu-based catalysts was carried out from the aspects of element doping and surface modification, and their electrocatalytic properties in OER were studied. In this paper, CuNiOx and CuCoOx thin films were successfully prepared by anodic deposition. SEM XRD was used to characterize the morphology and structure of the catalyst. It was proved that the film was amorphous. The results of electrochemical performance test showed that the OER catalytic activity of CuNiOx and CuCoOx samples was superior to that of CuO samples in different systems. The deposition time, deposition mode, element ratio and pH of the system were optimized. The results showed that the initial overpotential of OER was 320 MV, and the oxygen defect content in the binary oxide sample increased exponentially when the current density was 5 mA/cm2 and the catalytic activity was more than 10 h, the results showed that CuNiOx4: 1) had the best performance in the system of carbonated acid, and the initial overpotential of CuNiOx4: 1 was 320 MV. The group can accelerate the transfer rate of electron to the adsorbent and then enhance the catalytic activity of OER. At the same time, the self-supporting CuO / CF (foamed copper) electrode was successfully prepared by chemical etching in situ. The SEM XRD results show that the morphology and crystal structure of the catalysts are different at different calcination temperatures. The results of electrochemical performance test showed that CuO/CF with calcination temperature of 500 鈩，

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