Identifying Upper d-Band Edge as Activity Descriptor for Ammonia Oxidation on PtCo Alloys in Low-Temperature Direct Ammonia Fuel Cells
Fei Fang1,2,3，Qiyang Cheng1,2,3，Mengfan Wang2,3*, Yanzheng He2,3,Yunfei Huan4, Sisi Liu5, Tao Qian5, Chenglin Yan2,3,4（晏成林）*, Jianmei Lu1（路建美）*
1College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215006,China
2College of Energy, Key Laboratory of Core Technology of High Specific Energy Battery and Key Materials for Petroleum and Chemical Industry, Soochow University, Suzhou 215006, China
3College of Energy, Key Laboratory of Core Technology of High Specific Energy Battery and Key Materials for Petroleum and Chemical Industry, SoochowUniversity, Suzhou 215006, China
4School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
5School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
ACS Nano 2025, 19, 1260−1270
Abstract: Low-temperature direct ammonia fuel cell (DAFC) stands out as a more secure technology than the hydrogen fuel cell system, while there is still a lack of elegant bottom-up synthesis procedures for efficient ammonia oxidation reaction (AOR) electrocatalysts. The widely accepted d-band center, even with consideration of the d-band width, usually fails to describe variations in AOR reactivity in many practical conditions, and a more accurate activity descriptor is necessary for a less empirical synthesis path. Herein, the upper d-band edge, εu, derived from the d-band model, is identified as an effective descriptor for accurately establishing the descriptor–activity relationship. Using the PtCo alloy with varying atomic composition as an example, the εu value succeeds in reflecting the corresponding trends of AOR activity, showing striking linear correlation with a coefficient of determination (R2) as high as 0.90. The effectiveness of the established descriptor–activity relationship is verified experimentally. The optimum electrocatalyst delivers an excellent peak current density of 74.04 A g–1 at 5 mV s–1, and the assembled DAFC generates a high power density, outperforming the majority of the extensively reported systems. This work brings fundamental insights into the relationship between chemical reactivity and electronic structure and benefits rational optimization of AOR electrocatalyst for next-generation low-temperature DAFC.
Article information: //doi.org/10.1021/acsnano.4c13451
