Density Functional Theory Study of Single-Atom V, Nb, and Ta Catalysts on Graphene and Carbon Nitride for Selective Nitrogen Reduction
Chunjin Ren, Qianyu Jiang, Wei Lin, Yongfan Zhang, Shuping Huang, Kaining Ding
Abstract
Electrocatalytic nitrogen fixation using single-atom catalysts (SACs) offers a promising strategy for the sustainable production of NH3. On the basis of density functional theory, we systematically explored the potential for N2 electroreduction of single-atom catalysts (SACs) covering V, Nb, and Ta transition metal (TM) centers supported by graphene and g-C3N4 substrates. The single Nb-atom embedded on g-C3N4 nanosheet possesses outstanding nitrogen reduction reaction (NRR) catalytic activity and exhibits better performance than graphene with a considerably smaller maximum ΔG value (0.05 eV). The single Nb atom on g-C3N4 with more negative valence provides structural advantages for hosting empty d-orbitals for strong N2 and N2H adsorption, as well as more single d-electrons to further promote back-donation to activate the N≡N triple bond. This work may be helpful in developing more effective TM-based SACs for N2 reduction through varying substrate effect toward the same single-atom catalysts.