  Photoelectrocatalytic (PEC) reduction of N2 to ammonia (NH3) is emerging as
the potential alternative to overcome the standard Haber-Bosch approach. In
this communication, solar N2 reduction was demonstrated with molybdenum carbide
(Mo2C) co-catalyst assisted indium gallium nitride (InGaN) nanowires. The
effect of aiding Mo2C on InGaN NWs arrests the dark current and demonstrated
the saturation current under illumination was briefly elucidated. Large NH3
production of 7.2 gh-1cm-2 with high Faradaic efficiency of 12.6 % was realized
at -0.2 V vs. reversible hydrogen electrode for the Mo2C/GaN/InGaN
heterostructure. Notably, the proposed heterostructure also exemplifies
excellent stability and reproducibility with excellent selectivity in the
long-term chronoamperometry analysis. Further, the incorporation of GaN buffer
layer in between Mo2C and InGaN NWs was deeply investigated. From Density
Functional Theory (DFT) analysis, the incorporation of GaN buffer layer aids
the suitable band edge position for the transfer of photogenerated charge
carrier from InGaN to Mo2C co-catalyst, and unique 3d orbital of Mo2C is highly
suitable to hold N2 for effective reduction to NH3.
