Mo ₂ C‐Mo ₃ N ₂ Heterojunction Encapsulated Within N‐Doped Carbon Cage for Enhanced Selective Hydrogenation of CO ₂ to CO

Abstract The reverse water gas shift reaction (RWGS) can convert CO ₂ into CO, but the low activity and the inexpensive catalysts inhibit the industrialization process. As a potential material for the RWGS reaction, Mo ₂ C faces the challenges of high dispersibility and synthesis efficiency. Here, the Mo ₃ N ₂ ‐Mo ₂ C heterojunction encaged in N‐doped carbon matrix is synthesized using in situ carbonization method, which exhibits high activity under mild temperature. The CO ₂ conversion is 38.3%, the selectivity of CO is 99.1% upon 410 °C. The Space Time Yield is 17333.6 mgCO g _cat ⁻¹ h ⁻¹ (619.06 mmol g _cat ⁻¹ h ⁻¹ ) under 450 °C, and WHSV = 240 000 mL g _cat ⁻¹ h ⁻¹ , which is superior than traditional catalysts such as Cu–Zn–Al and noble metal catalysts. The catalyst shows 99.9% selectivity of CO, and maintaining equilibrium conversion for 200 h under 500 °C. The structure‐performance relationship studies indicate the synergistic effect of Mo ₂ C‐Mo ₃ N ₂ heterojunction active sites enhances H ₂ adsorption and dissociation significantly, which boosting the H assisted CO ₂ reduction reaction. Moreover, the N‐doped carbon cage confined environment greatly boosts the catalyst stability. This work provides a simple and feasible strategy for the synthesis of highly dispersed Mo ₂ C‐Mo ₃ N ₂ heterojunction active site for CO ₂ hydrogenation reaction, and a way to boost the H ₂ activation capacity of Mo ₂ C catalyst.