TY  - JOUR
AU  - Agharezaei, Parastoo
AU  - Tomohiro, Noguchi Goroh
AU  - Kobayashi, Hirokazu
AU  - Schlenz, Hartmut
AU  - Yamauchi, Miho
AU  - Ghuman, Kulbir Kaur
TI  - Unraveling the Enhanced N 2 Activity on CuNi Alloy Catalysts for Ammonia Production: Experiments, DFT, and Statistical Analysis
JO  - The journal of physical chemistry / C
VL  - 128
IS  - 9
SN  - 1932-7447
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2024-02110
SP  - 3703 - 3717
PY  - 2024
AB  - One of the main challenges in designing catalysts for ammonia synthesis is tocreate active sites on the surface of the catalyst that prefers to reduce the strong N2 moleculedespite its highly stable structure. Binary alloys have been demonstrated as potential ammoniasynthesis catalysts in the literature. However, for binary alloys to be commercially viable, oneneeds to improve their catalytic activity for N2 reduction by strategically manipulating theseveral unique active sites present on their surface. Herein, by using computational tools, wecreated five different compositions of CuxNi1−x (0.5 ≤ x ≤ 0.9) alloys via special quasi-randomstructure (SQS) and genetic algorithm (GA). The alloy with about 50% of Cu and 50% of Ni ispredicted to have the highest catalytic activity based on the shift of the d-band center towardthe Fermi level. We then synthesized MgO-supported Cu0.5Ni0.5 nanoparticles and comparedtheir activity for ammonia synthesis with that of Ni/MgO and Cu/MgO. It was found that theMgO-supported Cu0.5Ni0.5 alloy possesses 21 times higher activity than Cu/MgO and 3 timeshigher than Ni/MgO for ammonia synthesis, confirming the computational results. Todemonstrate the impact of alloying on the catalytic activity, we further investigated all thepossible unique sites on the surface of the Cu0.5Ni0.5 alloy for nitrogen reduction reaction (NRR) via density functional theory(DFT). The investigation of the 96 unique active sites on the Cu0.5Ni0.5 surface demonstrated that the position and concentration ofNi atoms near each investigated adsorption site have a linear correlation with the adsorption energy of the N2. Along with thestructural and electronic properties of the active sites modified by Ni, orientation of the N2 molecule also plays an important role indetermining the activity of the CuNi catalyst. These findings not only explained the notable increase in the activity of CuNi catalystscompared to the pure metals for NH3 synthesis but also offered critical insights required to tailor the specific surface environment ofCuNi catalysts for NRR. This knowledge can serve as a foundation for further developments in designing binary alloy catalysts forsustainable ammonia synthesis.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001173697100001
DO  - DOI:10.1021/acs.jpcc.3c06417
UR  - https://juser.fz-juelich.de/record/1024354
ER  -