This study presents a novel Sn-based MXene/MAX hybrid, Sn@Ti3CTx/Ti2SnC-V, synthesized through controlled etching of Sn@Ti2SnC MAX phase. This hybrid is demonstrated to be an efficient electrocatalyst for the electroreduction of nitrogen (N2) to ammonia (NH3). The presence of Sn vacancies and the highly dispersed Sn active sites in the MXene/MAX heterostructure synergistically enhance the catalytic performance. The Sn@Ti3CTx/Ti2SnC-V catalyst exhibits an optimal NH3 yield of 28.4 μg h⁻¹ mgcat⁻¹ and a Faradaic efficiency (FE) of 15.57% at -0.4 V versus reversible hydrogen electrode (RHE) in 0.1 M Na2SO4 electrolyte. The catalyst also demonstrates excellent durability, with a stable current density after 18 hours of continuous potentiostatic electrolysis. Additionally, a PV-EC system based on this catalyst is developed, achieving a maximum NH3 yield of 10.53 μg h⁻¹ mg⁻¹ using a commercial photovoltaic panel and air as the nitrogen source. A techno-economic analysis shows that this system is economically feasible, making it a promising approach for large-scale green ammonia production.This study presents a novel Sn-based MXene/MAX hybrid, Sn@Ti3CTx/Ti2SnC-V, synthesized through controlled etching of Sn@Ti2SnC MAX phase. This hybrid is demonstrated to be an efficient electrocatalyst for the electroreduction of nitrogen (N2) to ammonia (NH3). The presence of Sn vacancies and the highly dispersed Sn active sites in the MXene/MAX heterostructure synergistically enhance the catalytic performance. The Sn@Ti3CTx/Ti2SnC-V catalyst exhibits an optimal NH3 yield of 28.4 μg h⁻¹ mgcat⁻¹ and a Faradaic efficiency (FE) of 15.57% at -0.4 V versus reversible hydrogen electrode (RHE) in 0.1 M Na2SO4 electrolyte. The catalyst also demonstrates excellent durability, with a stable current density after 18 hours of continuous potentiostatic electrolysis. Additionally, a PV-EC system based on this catalyst is developed, achieving a maximum NH3 yield of 10.53 μg h⁻¹ mg⁻¹ using a commercial photovoltaic panel and air as the nitrogen source. A techno-economic analysis shows that this system is economically feasible, making it a promising approach for large-scale green ammonia production.