摘要
废水中存在的肼和尿素会对环境造成严重污染。利用电化学氧化技术处理含肼和尿素的废水,既可以有效处理废水,实现氮循环,又能将肼和尿素作为新型燃料,有助于新能源的发展。然而,目前实现肼氧化(HzOR)和尿素氧化(UOR)的电化学技术仍存在挑战。因此,开发低成本、高效且稳定性好的电催化剂是实现这一技术的先决条件。在本文中,我们采用水热-碱刻蚀-磷化的三步方法,制备了一种富含阳离子缺陷的双金属磷化物Ni_(2)P/CoP_(3)催化剂(简称Ni_(2)P/CoP_(3)-Zn^(vac)),并将其应用于肼氧化和尿素氧化。该催化剂由贫磷的Ni_(2)P和富磷的CoP_(3)两种不同性质的磷化物组成。CoP_(3)中富集的磷含有大量的负电荷,有利于吸附带正电荷的中间物种;而Ni_(2)P中磷含量较少,金属含量高,具有良好的导电性,可以确保快速的反应动力学。通过物理表征和电化学测试,证实了Ni_(2)P/CoP_(3)的成功合成和其独特的电子结构。电子顺磁测试(EPR)证明了阳离子空位的存在,大量的阳离子空位缺陷有助于增加活性位点的数量,从而提升催化性能。因此,该催化剂在肼氧化和尿素氧化方面表现出色。仅需-47 mV(HzOR)和1.311 V(UOR)的电位即可产生10 mA·cm^(-2)的电流密度。Tafel斜率分别为54.3 mV·dec^(-1)(HzOR)和37.24 mV·dec^(-1)(UOR)。Ni_(2)P/CoP_(3)-Zn^(vac)在HzOR和UOR方面的性能远优于单独的Ni_(2)P和CoP_(3),也优于未经碱刻蚀的镍钴磷化物。基于以上的测试结果,我们将Ni_(2)P/CoP_(3)-Zn^(vac)催化剂应用于直接肼燃料电池(DHzFC)和直接尿素-双氧水燃料电池(DUHPFC)的阳极,测试表明DHzFC和DUHPFC的最大功率密度分别为229.01和16.22mW·cm^(-2)。更为重要的是,DHzFC和DUHPFC能够稳定工作24 h,性能几乎不衰退。此外,Ni_(2)P/CoP_(3)-Zn^(vac)材料还可应用于自制的锌-肼燃料电池,并展示出良好的实际应用潜力。综上所述,本研究通过一系列方法制�
Handling hydrazine/urea wastewater through electrochemical oxidation technology(HzOR/UOR)holds significant importance for sewage disposal and nitrogen recycling,as the presence of hydrazine/urea leads to severe environmental issues.On the other hand,hydrazine/urea could potentially serve as a new type of fuel.However,at present,this remains a considerable challenge.The development of a low-cost,highly efficient,and stable electrocatalyst stands as a prerequisite for achieving this goal.In this study,a novel Ni_(2)P/COP_(3)-Zn^(vac)bimetallic phosphide catalyst is designed and constructed using a hydrothermal-alkali etching-phosphating three-step method.This catalyst integrates P-rich CoP_(3),P-poor metallic Ni_(2)P,and abundant Zn^(2+)cation vacancies into a single structure for HzOR/UOR.Copious P in CoP_(3)provides a wealth of negative electrons,which aids in the adsorption of positive reactive intermediates.Meanwhile,P-poor metallic Ni_(2P)exhibits excellent electrical conductivity,ensuring rapid reaction dynamics.Both physical and electrochemical experiments confirm the successful creation of the Ni_(2)P/CoP_(3)-Zn^(vac)heterojunction,along with the distinctive electron structure of Ni_(2P)and CoP_(3).Electron paramagnetic resonance(EPR)results validate the presence of cation vacancies,which significantly enhance the density of active sites.Consequently,this innovative Ni_(2)P/CoP_(3)-Zn^(vac)hete rojunction catalyst displays remarkable electrocatalytic activity,achieving a potential of-47 mV/1.311 V to attain 10 mA·cm^(-2)for HzOR and UOR,respectively.The Tafel slopes of 54.3 and 37.24 mV·dec^(-1)for HzOR and UOR are significantly smaller than those of single-phased Ni_(2P)and CoP_(3),as well as the two-phased phosphide without alkali etching.Building upon the excellent HzOR/UOR performance of the Ni_(2)P/CoP_(3)-Zn^(vac)heterojunction,a two-electrode cell for direct hydrazine fuel cells(DHzFC)and direct urea-hydrogen peroxide fuel cells(DUHPFC)is assembled with a Ni_(2)P/CoP_(3)-Zn^(vac)anode.This configur
作者
谭雯娟
叶勇
孙秀娟
刘备
周佳佳
廖海龙
吴秀琳
丁锐
刘恩辉
高平
Wenjuan Tan;Yong Ye;Xiujuan Sun;Bei Liu;Jiajia Zhou;Hailong Liao;Xiulin Wu;Rui Ding;Enhui Liu;Ping Gao(Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education,College of Chemistry,Xiangtan University,Xiangtan 411105,Hunan Province,China.)
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2024年第6期63-66,共4页
Acta Physico-Chimica Sinica
基金
湖南省教育厅一般项目(20C1774)
湖南省自然科学基金(2021JJ40530,2022JJ40428)资助。
