Theoretical and Comparative Analysis of Graphdiyne and Confined Flexible Nitrogen-Doped Graphdiyne-Supported Single-Atom Catalysts for Electrochemical Nitrogen Reduction

Abstract

To develop high-performance and low-cost catalysts for electrochemical nitrogen reduction reaction (eNRR) in producing ammonia, a promising alternative to the Haber–Bosch process continues to be a substantial challenge. Herein, by using density functional theory calculations, single-atom-supported pristine and nitrogen-doped (N-doped) graphdiyne (GDY) monolayer-catalyzed eNRR were investigated to realize high performance via rational design. Candidate catalysts include 10 different transition-metal (M = Cr, Mn, Fe, Co, Ni, Cu, Mo, W, Re, and Ru) single-atom-anchored GDY monolayers (M1/GDY) and three different types of N-doped (sp 2-N and sp-N) GDY monolayers (M1/Nn-GDY, n = 1–3), with 40 single-atom catalysts (SACs). Both Mo1/N3-GDY and W1/N3-GDY were screened out with rather low theoretical onset potentials of merely −0.36 and −0.41 V, respectively. Further investigation of the exemplar Mo1/N3-GDY system shows that it has high selectivity, stability, and activity toward ammonia. The synergy effect between single-atom Mo and the confined flexibility substrate gives rise to self-adjustment of the coordination microenvironment of Mo1/N3-GDY, that is, this doped first coordination sphere sp-N is confined, yet shows steric flexibility, and transfers into sp 2-N without Mo-N bond formation when single-atom Mo is anchored. Therefore, the system regulates adsorption pattern and strength of N2and intermediates, and finally boosts the performance. This work provides a new idea of using a confined flexibility substrate to construct SACs for efficient synthesis of ammonia at ambient conditions.

Emerging Xene‐Based Single‐Atom Catalysts: Theory, Synthesis, and Catalytic Applications

“…In addition, as novel 2D carbon allotrope comprising sp-and sp 2 -hybridized carbon atoms, emerging Xene GDY possesses uniform pores, natural anchoring sites, excellent electrical conductivity and high stability, which endows it as a fascinating matrix for supporting SA catalysts. [60,109,[112][113][114][115][116][117] For example, in 2020, Zhai et al [109] 7a). Based on standard ii, the E b s of N 2 molecule on Cr SA-GDY, Rh SA-GDY, and Pd SA-GDY surfaces are approaching 0 eV (Figure 7b), and the calculated N-N bond length (Figure 7c) from the viewpoint of end-on and side-on configurations shows that the length of N-N bond is not largely elongated, both of which suggest that they are not ideal candidates for the NRR electrocatalysts.…”

“…Emerging Xenes with low-cost and environmentally-benign properties, have recently demonstrated to not only largely facilitate N 2 adsorption and activation but also efficiently suppress the competitive HER. [50,62,96,113,144,149,244,245,[251][252][253][254] For example, in 2022, Duan et al [244] reported on Xene GDY NSs as support matrixes to anchor low-valence metal (M) SAs (M = Cr, Mo, W, Mn, and Re) for improved electrochemical NRR via metal-to-N 2 𝜋-backdonation. The fabrication process can be seen in Figure 16a.…”

“…In addition, as novel 2D carbon allotrope comprising sp‐ and sp 2 ‐hybridized carbon atoms, emerging Xene GDY possesses uniform pores, natural anchoring sites, excellent electrical conductivity and high stability, which endows it as a fascinating matrix for supporting SA catalysts. [60, 109,112–117 ] For example, in 2020, Zhai et al. [ 109 ] systematically investigated TM SA (TM = Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ru, Rh, Pd, and Ag)‐GDY for NRR by DFT calculation.…”

Design of Efficient Oxygen Reduction Reaction Catalysts with Single Transition Metal Atom on N-Doped Graphdiyne

“…Further theoretical analysis reveals that the incorporation of electronegativity nitrogen atoms makes the supported Pt single atom achieve a unique atomic state, which obviously promotes its catalytic performance and stability . Remarkably, Ru et al systemically investigated a variety of TM single atoms on different GDY/NGDY supports utilizing density functional theory (DFT), and Mo-doped N 3 -GDY were screened out with extremely low theoretical onset potentials …”

“…Further theoretical analysis reveals that the incorporation of electronegativity nitrogen atoms makes the supported Pt single atom achieve a unique atomic state, which obviously promotes its catalytic performance and stability. 21 structure remains ambiguous and lacks experimental evidence, seriously restricting their practical application. Recent theoretical research conducted in our group has revealed that atomically dispersed TMs can induce charge redistribution, which in turn changes the local electronic structure near the active center.…”