Highly Efficient Photo-/Electrocatalytic Reduction of Nitrogen into Ammonia by Dual-Metal Sites

The
photo-/electrocatalytic nitrogen reduction reaction (NRR) is
an up and coming method for sustainable NH3 production;
however, its practical application is impeded by poor Faradaic efficiency
originating from the competing hydrogen evolution reaction (HER) and
the inert NN triple bond activation. In this work, we put
forth a method to boost NRR through construction of donor–acceptor
couples of dual-metal sites. The synergistic effect of dual active
sites can potentially break the metal-based activity benchmark toward
efficient NRR. By systematically evaluating the stability, activity,
and selectivity of 28 heteronuclear dual-atom catalysts (DACs) of
M1M2/g-C3N4 candidates, FeMo/g-C3N4 is screened out as an effective electrocatalyst for
NRR with a particularly low limiting potential of −0.23 V for
NRR and a rather high potential of −0.79 V for HER. Meanwhile,
TiMo/g-C3N4, NiMo/g-C3N4, and MoW/g-C3N4 with suitable band edge positions
and visible light absorption can be applied to NRR as photocatalysts.
The excellent catalytic activity is attributed to the tunable composition
of metal dimers, which play an important role in modulating the binding
strength of the target intermediates. This work may pave a new way
for the rational design of heteronuclear DACs with high activity and
stability for NRR, which may also apply to other reactions.