Phosphorene‐Supported Transition‐Metal Dimer for Effective N₂ Electroreduction

Abstract

The electrochemical reduction of N2 to NH3 at ambient conditions is a promising alternative to the energy‐intensive, high‐temperature, high‐pressure Haber‐Bosch process. But it is extremely challenging to find an electrocatalyst that can effectively activate N2 and reduce it to NH3. From first principles density functional theory, we found that the Ti dimer supported on single‐layer phosphorene can be used as a promising electrocatalyst for N2 capture and conversion to NH3. The overpotential (relative to the standard hydrogen electrode) was found to be as low as 0.20, much lower than those predicted on the Ti surface (1 to 1.5 V) or their nitrides (0.5 to 1 V). In addition, we found that hydride is involved in the N2 reduction on the Ti dimer catalyst via formation of Ti2‐H species, and the hydride would favorably transfer onto the adsorbed N2* to form *NNH intermediate and further reduced to NH3. Moreover, we also examined other first‐row transition metal dimers, and found that Sc and Fe dimer to be potential catalysts which could catalyze N2 reduction at a low overpotential of about 0.21 and 0.45 V, respectively. Our predictions hence suggest Ti, Sc and Fe dimer clusters supported on phosphorene as promising electrocatalysts for N2 reduction to NH3.

“More is Different:” Synergistic Effect and Structural Engineering in Double‐Atom Catalysts

“…[18] The authors first screened out 25 homonuclear M 2 -Pc monolayers with high thermodynamic and electrochemical stabilities, after which N 2 adsorption calculations showed that eight M 2 -Pc DACs (M = Cr, Mn, Mo, W, Re, Ti, V, and Ta) can realize strong N 2 chemisorption, which is a prerequisite for NRR catalysts. Furthermore, Gibbs free energy calculations indicated that Ti 2 , V 2 , and Re 2 -Pc can cobalance TM 2 @phosphorene (TM = Sc-Cu) Ti 2 @phosphorene −0.20 Distal *NH 2 →*NH 3 2019 [103] Fe-TM@graphene-based substrate (GS) Fe-Ti@GS −0.88 Enzymatic *N 2 →*N 2 H 2020 [105] Fe 2 @C-DV/G, N-DV/G, g-C 3 N 4 , GDY…”

“…[101] The synergistic effect between Fe atoms and the MoS 2 substrate provides electron depletion and vacant orbitals for lone-pair electrons in N 2 , and electron back-donation from Fe 2 to N 2 enhances N 2 activation. Other 2D materials, such as graphdiyne, [102] phosphorene, [103] C 2 N, [88a,104] and C 3 N 4 , [102b] can also serve as substrates for NRR DACs.…”

Heterogeneous Atomic Catalysts Overcoming the Limitations of Single-Atom Catalysts

“…Ni 1 –Mn 1 , Ni 1 –Cu 1 , and Ag 2 /graphene dimer catalyst were also reported to be active in the CO 2 RR. Promising dimers structures have been additionally predicted by DFT calculation for CO oxidation, , ORR, , NRR, − and CO 2 RR. − …”

2D Metal‐Free Nanomaterials Beyond Graphene and Its Analogues toward Electrocatalysis Applications

“…Jiang et al theoretically predicted that Ti, Sc, and Fe dimer cluster could be anchored on phosphorene as efficient electrocatalysts for NRR. [103] They found that Ti 2 /P system showed optimal N 2 capture and maximal NH 3 production with an overpotential of Reproduced with permission. [83] Copyright 2018, Wiley-VCH.…”