1. Revealing the activity origin of ultrathin nickel metal–organic framework nanosheet catalysts for selective electrochemical nitrate reduction to ammonia: Experimental and density functional theory investigations.
- Author
-
Pan, Fan, Zhou, Jianjun, Wang, Tian, Zhu, Yunqing, Ma, Hongrui, Niu, Junfeng, and Wang, Chuanyi
- Subjects
- *
ELECTROLYTIC reduction , *FOAM , *DENITRIFICATION , *METAL-organic frameworks , *DENSITY functional theory , *NICKEL catalysts , *AMMONIA , *ACTIVATION energy , *CATALYSTS - Abstract
[Display omitted] The electrochemical nitrate reduction reaction (NitRR) affords a sustainable way for nitrate mitigation and ammonia synthesis, but there are still some problems such as poor nitrate conversion, low ammonia selectivity, and slow reaction kinetics. A clear structure-performance relationship is essential for designing efficient catalysts and understanding the reaction mechanisms. Herein, ultrathin nickel metal–organic framework (Ni-MOF) nanosheets supported on Ni foam featuring a well-defined stable structure, large electrochemically active surface area, and low electron transport resistance were prepared by a one-step solvothermal process. At −1.4 V, the nitrate reduction, rate constant, ammonia selectivity, and yield reached 96.4%, 0.448 h−1, 80%, and 110.13 ug·h−1·cm−2, respectively. Experimental and theoretical studies demonstrated that the hydroxyl-ligated Ni atoms exhibited higher nitrate adsorption properties and lower activation energy towards NitRR compared to carboxylic acid-ligated Ni atoms. Mechanism investigations revealed a nitrate-to-ammonia reaction pathway involving multiple intermediate species on Ni-MOF nanosheet catalysts. This work offers a new avenue to construct highly efficient electrocatalysts for the selective transformation of nitrate to valuable ammonia. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF