Sun Xinghao, Liang Yanqin, Jiang Hui, Li Zhaoyang, Wu Shuilin, Gao Zhonghui, Cui Zhenduo, Fan Guilan, Zhu Shengli, Xu Wence
School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China.
State Key Laboratory of Precious Metal Functional Materials, Tianjin 300350, China.
ACS Appl Mater Interfaces. 2025 May 14;17(19):28256-28266. doi: 10.1021/acsami.5c03383. Epub 2025 Apr 30.
The rechargeable Zn-nitrate battery presents a promising strategy for renewable energy conversion, ammonia production, and sewage treatment. Despite achieving excellent performance with transition metal-based electrocatalysts, the structure evolution of the electrocatalyst during Zn-nitrate battery charging/discharging and the corresponding reaction mechanism on nitrate reduction reaction (NORR) are still unclear. Inspired by the structural reconstruction in the charging process, nanoporous CoP/CoOOH prepared by dealloying and anodic oxidation is reported as an electrocatalyst for NORR, achieving remarkable catalytic performance (ammonia yield rate: 1.93 mmol h cm, Faradaic efficiency: 94.18%) with a high cathodic energy efficiency of 34.51%. Additionally, the assembled rechargeable Zn-nitrate battery delivers a power density of 31.99 mW cm with a high charge-discharge stability. In-situ spectroscopy investigation reveals the generation of a CoP/CoO heterosturcture through a synergetic redox reaction involving the cobalt species and nitrate ions during NORR, which enhances the approach of potassium-ionized water and improves ammonia generation kinetics by regulating the NO and *NH generation. Density functional theoretical calculation further illustrates that CoP/CoO heterostructure optimizes the adsorption of the *NO intermediate and enables an energetically favorable rate-limiting *NOH formation step. The unique structural evolution and nitrate activation mode of cobalt-based heterostructure would provide new insights on designing efficient electrocatalysts for nitrate reduction and rechargeable Zn-nitrate battery.
可充电硝酸锌电池为可再生能源转换、氨生产和污水处理提供了一种很有前景的策略。尽管过渡金属基电催化剂实现了优异的性能，但硝酸锌电池充放电过程中电催化剂的结构演变以及相应的硝酸盐还原反应（NORR）反应机理仍不清楚。受充电过程中结构重构的启发，报道了通过脱合金和阳极氧化制备的纳米多孔CoP/CoOOH作为NORR的电催化剂，实现了显著的催化性能（氨产率：1.93 mmol h cm，法拉第效率：94.18%），阴极能量效率高达34.51%。此外，组装的可充电硝酸锌电池具有31.99 mW cm的功率密度和高充放电稳定性。原位光谱研究表明，在NORR过程中，通过涉及钴物种和硝酸根离子的协同氧化还原反应生成了CoP/CoO异质结构，这增强了钾离子化水的接近，并通过调节NO和NH的生成来改善氨生成动力学。密度泛函理论计算进一步表明，CoP/CoO异质结构优化了NO中间体的吸附，并使能量上有利的限速*NOH形成步骤成为可能。钴基异质结构独特的结构演变和硝酸盐活化模式将为设计高效的硝酸盐还原电催化剂和可充电硝酸锌电池提供新的见解。
