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Chi et al. J. Mater. Inf. 2025, 5, 11 https://dx.doi.org/10.20517/jmi.2024.49 Page 5 of 12

n × N + (3 - n) × N , m catalyst = 72 × N + m , where n represents the number of Fe atoms, and N , N
Fe
Mo
Fe
Mo
C
TMs
and N are the corresponding molar mass.
C
RESULTS AND DISCUSSION
In the periodic table, the elements from groups V, VI, and VIII are often favored in the field of
electrocatalysis due to their unique outer electron arrangements. Therefore, we select V, Cr, Fe, Nb, Mo, Ru,
Ta, W, and Os as candidate elements for the catalyst design. For electrocatalytic urea synthesis, U , E , and
L
b
E of the products are critical factors. Therefore, we first calculate the U value for each element as a catalyst
ad
L
in the electrocatalytic synthesis of urea, the E ad*N2+*CO - E value for the C-N coupling process, and the E
ad
b
value for the product [Figure 1B], and select the top three elements with the best performance. As seen in
the results from Table 1, it is clear that Fe, Mo, and W present great potential. Considering that these three
factors do not fully represent the entire reaction process, we also calculated the E - ΔE curve for each
ad
reaction step in the electrocatalytic synthesis of urea using each element as a catalyst [Supplementary
Figures 1-6]. Since each reaction step requires suitable ΔE and E , we select four elements in the middle of
ad
each step’s curve; the element screen is shown in Table 2. Here as well, we found that Mo, W, and Fe exhibit
good performance during the reaction process. According to our design, among the three atoms, there must
be both strong and weak adsorptions to allow intermediates to change configurations on the catalyst and
regulate adsorption energy. In addition, considering that the melting point of W is as high as 3,400 °C,
which poses an obstacle to its synthesis, we finally selected Mo and Fe for the catalyst design (here, Fe was
chosen as the weak adsorption atom). We note that Fe and Mo have been widely considered as active sites
to weaken the N≡N, such as the applications of FeMo S and Fe/Mo-N-C in NRR [29,30] . The unoccupied d-
3 4
orbitals of the FeMo cluster can accept lone pair electrons from N . Conversely, the occupied d-orbitals of
2
the FeMo cluster can donate electrons to the antibonding orbitals of N , thereby weakening the N≡N .
[31]
2
Additionally, the synergistic interaction between Fe and Mo can significantly enhance catalytic
performance. Efficient electron transfer is facilitated by the strong orbital coupling between Fe-3d and
Mo-4d. This ensures not only excellent electron conduction from the catalyst to the adsorbed intermediate,
[32]
but also remarkable stability of the catalyst . Therefore, we select Fe and Mo loaded onto γ-GDY to form
Fe Mo (x = 0, 1, 2, 3) as the electrocatalyst.
3-x
x
Figure 1C builds a Fe Mo @γ-GDY (x = 0, 1, 2, 3) model, which generates four structures: Mo @γ-GDY,
x
3-x
3
Fe @γ-GDY, Fe Mo@γ-GDY, and FeMo @γ-GDY. Table 3 presents the calculated ΔG and E values for all
2
3
b
max
2
the four cases. It is noteworthy that the electrocatalytic urea synthesis process on Fe @γ-GDY cannot be
3
[33]
successfully completed. According to the findings of Zhou et al. , a lower Hirshfeld charge on N points
[Supplementary Table 1] indicates weaker nucleophilicity, making N less sensitive to adsorption (or
2
+
alternatively, allowing H to be more easily adsorbed by the underlying Fe). It is clear from Table 3 that
Fe Mo@γ-GDY possesses excellent electrocatalytic thermodynamic and kinetic performances for urea
2
synthesis (i.e., much lower ΔG and E values). Here, the excellent performance of Fe Mo@γ-GDY is in line
b
max
2
with our design described in the Introduction section.
The optimal structure of Fe Mo@γ-GDY is shown in Figure 2A. The average bond length of the three longer
2
edges of the C18 hexagonal hole is 6.78 Å, and the average bond length between the metal and C atoms is
2.07 Å, which is sufficient to accommodate the Fe Mo cluster. To assess the electronic conductivity of
2
Fe Mo@γ-GDY, an essential feature for electrocatalysis, the density of states (DOS) was calculated. As
2
shown in Figure 2B, the DOS crosses the Fermi level, which demonstrates the metallic characteristics of
Fe Mo@γ-GDY. To explore the stability of Fe Mo@γ-GDY, its frequency and formation energy were
2
2
evaluated. Figure 2C provides the frequency distribution for Fe Mo@γ-GDY, where the absence of
2
imaginary frequencies indicates excellent stability. In addition, a negative formation energy of E =
form