Coordination tailoring of Cu single sites on C ₃N ₄ realizes selective CO ₂ hydrogenation at low temperature

Abstract

CO ₂ hydrogenation has attracted great attention, yet the quest for highly-efficient catalysts is driven by the current disadvantages of poor activity, low selectivity, and ambiguous structure-performance relationship. We demonstrate here that C ₃N ₄-supported Cu single atom catalysts with tailored coordination structures, namely, Cu–N ₄ and Cu–N ₃, can serve as highly selective and active catalysts for CO ₂ hydrogenation at low temperature. The modulation of the coordination structure of Cu single atom is readily realized by simply altering the treatment parameters. Further investigations reveal that Cu–N ₄ favors CO ₂ hydrogenation to form CH ₃OH via the formate pathway, while Cu–N ₃ tends to catalyze CO ₂ hydrogenation to produce CO via the reverse water-gas-shift (RWGS) pathway. Significantly, the CH ₃OH productivity and selectivity reach 4.2 mmol g ^–1 h ^–1 and 95.5%, respectively, for Cu–N ₄ single atom catalyst. We anticipate this work will promote the fundamental researches on the structure-performance relationship of catalysts.

Abstract

CO ₂ hydrogenation has attracted intense scientific attention yet suffers from the disadvantage of poor activity and low selectivity. Here, the authors report that Cu single atom catalysts with tailored coordination environments on C ₃N ₄ serve as highly selective catalysts for CO ₂ hydrogenation.