催化学报 ›› 2022, Vol. 43 ›› Issue (12): 3107-3115.DOI: 10.1016/S1872-2067(21)64047-0

• 论文 • 上一篇    下一篇

三维多孔碳限域的磷化钴电催化剂用于高效的锌-空气电池和水分解

舒欣欣a,, 杨茅茂a,, 刘苗苗a, 王怀生b, 张进涛a,*()   

  1. a山东大学化学与化工学院, 胶体与界面化学教育部重点实验室, 山东济南250100
    b聊城大学化学与化工学院, 山东聊城252059
  • 收稿日期:2022-01-21 接受日期:2022-02-22 出版日期:2022-12-18 发布日期:2022-10-18
  • 通讯作者: 张进涛
  • 作者简介:第一联系人:

    共同第一作者.

  • 基金资助:
    国家自然科学基金(22175108);山东省杰青青年基金(ZR2020JQ09);山东省泰山学者计划(tsqn20161004);山东省高校青年学者创新团队项目(2019KJC025)

In-situ formation of cobalt phosphide nanoparticles confined in three-dimensional porous carbon for high-performing zinc-air battery and water splitting

Xinxin Shua,, Maomao Yanga,, Miaomiao Liua, Huaisheng Wangb, Jintao Zhanga,*()   

  1. aKey Laboratory for Colloid and Interface Chemistry of State Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, Shandong, China
    bSchool of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong, China
  • Received:2022-01-21 Accepted:2022-02-22 Online:2022-12-18 Published:2022-10-18
  • Contact: Jintao Zhang
  • About author:First author contact:Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(22175108);Natural Science Foundation of Shandong Province(ZR2020JQ09);Taishan Scholars Program of Shandong Province(tsqn20161004);Project for Scientific Research Innovation Team of Young Scholar in Colleges, Universities of Shandong Province(2019KJC025)

摘要:

合理设计高效稳定的氧还原反应(ORR)和氧析出反应(OER)双功能电催化剂对于提升可充电锌-空气电池的能量密度和循环性至关重要. 为了降低对贵金属基催化剂的依赖, 过渡金属-碳基复合电催化剂引起了研究人员的广泛关注.

本文以植酸掺杂的聚苯胺为碳前驱体, 通过调节pH可控络合吸附钴离子, 在氨气气氛中一步热解获得了磷化钴纳米颗粒镶嵌的氮、磷共掺杂的三维多孔碳电催化剂. 三维多孔碳基底能够缓解高温热解引起的金属颗粒团聚、失活等问题, 原位形成的磷化钴纳米颗粒能够协同促进电催化ORR, OER, 析氢反应(HER)活性, 从而提高可充电锌-空气电池性能. 通过调节苯胺与植酸的投料比, 制备了短枝状(B-PANI-PA)和纤维状(F-PANI-PA)两种不同形貌的聚苯胺前驱体. 傅里叶变换红外光谱测试结果表明, 植酸成功掺杂至聚苯胺骨架中. 随后, 利用紫外-可见吸收光光谱研究了分散液pH对钴离子吸附量的影响. 将pH从4.0调至7.3后, 位于510 nm处归属于水合钴离子的吸收峰强度明显减弱, 表明其吸附钴离子的能力增强. X射线粉末衍射结果表明, 由两种不同的聚苯胺前驱体吸附钴离子后热解合成的磷化钴具有不同的暴露晶面, 均为CoP和CoP3的混合相. 相比之下, 吸附更多钴离子的B-PANI-PA-Co-7.3样品则对应于Co2P物相. 该形成过程主要归因于: 钴含量一定时, 在氨气还原性气氛中, 随时间的延长植酸热分解会逐步释放磷源, 从而形成富磷元素的磷化钴; 反之, 当钴过量时, 则更倾向于生成富钴元素的磷化钴. X射线光电子能谱结果再次验证了高温过程中磷化钴的原位形成和磷元素对碳基底的掺杂作用.

电催化氧还原反应性能测试表明, CoPX@B-NPC催化剂展现出良好的半波电位(E1/2 = 0.84 V vs. RHE), 高的动力学电流密度(5.2 mA cm-2), 较好的四电子选择性, 较大的电化学活性面积(19.8 mF cm-2). 以CoPX@B-NPC作为空气电极催化剂组装的可充电液态电解质锌-空气电池展现出高达1.49 V的开路电压, 峰值功率密度可达到368 mW cm-2, 高于商用Pt/C-RuO2混合催化剂组装的电池(237 mW cm-2). 在25.0 mA cm-2的电流密度下, CoPX@B-NPC组装的电池的比容量高达762 mAh gZn-1. 长循环充放电测试中, 电池在260 h内没有明显的电压衰减. 值得注意的是, 以CoPX@B-NPC组装的柔性固态电解质锌-空气电池的开路电压可达到1.48 V, 可与液态电解质锌-空气电池相媲美. 此外, CoPX@B-NPC组装的电池在0.81 V下可达到峰值功率密度160 mW cm-2. 在柔性测试中, 电池展现出良好的机械稳定性, 弯折时仍保持稳定的充放电循环性能. 由锌-空气电池驱动的水分解装置具有良好的产气效率, 体现了该催化剂的多效催化活性. 综上, 本文为发展高效、稳定的三维多孔碳基复合催化剂提供了一种方便有效的合成方法.

关键词: 磷化钴, 三维多孔碳, 电催化, 锌-空气电池, 水分解

Abstract:

The rational design of efficient and stable carbon-based electrocatalysts for oxygen reduction and oxygen evolution reactions is crucial for improving energy density and long-term stability of rechargeable zinc-air batteries (ZABs). Herein, a general and controllable synthesis method was developed to prepare three-dimensional (3D) porous carbon composites embedded with diverse metal phosphide nanocrystallites by interfacial coordination of transition metal ions with phytic acid-doped polyaniline networks and subsequent pyrolysis. Phytic acid as the dopant of polyaniline provides favorable anchoring sites for metal ions owing to the coordination interaction. Specifically, adjusting the concentration of adsorbed cobalt ions can achieve the phase regulation of transition metal phosphides. Thus, with abundant cobalt phosphide nanoparticles and nitrogen- and phosphorus-doping sites, the obtained carbon-based electrocatalysts exhibited efficient electrocatalytic activities toward oxygen reduction and evolution reactions. Consequently, the fabricated ZABs exhibited a high energy density, high power density of 368 mW cm‒2, and good cycling/mechanical stability, which could power water splitting for integrated device fabrication with high gas yields.

Key words: Cobalt phosphide, Three-dimensional porous carbon, Electrocatalysis, Zinc-air battery, Water splitting.