Nitrogen-coordinated single metal atoms supported on carbon (M–N_x/C) catalysts exhibit remarkable activities during the electrochemical CO₂ reduction reaction (CO₂RR). However, exploring the relationship between the support properties, such as morphology and electron conductivity, and catalytic activity remains challenging because conventional high-temperature pyrolysis induces multiple M–N_x coordination in the M–N_x/C catalysts. Herein, a series of nitrogen-doped porous carbon supports with various pore sizes and degrees of graphitization were prepared, and Ni–N₄ active sites were subsequently loaded by anchoring Ni phthalocyanine (NiPc). We found that the electron conductivity of the support is crucial for enhancing the CO selectivity in the low-potential region (from −0.5 to −0.7 V_RHE). However, effective CO₂ transport, which is strongly affected by the morphology of the support, has a more dominant effect than electron conductivity on catalytic activity. The optimized catalyst exhibits outstanding CO₂RR performances owing to the presence of mesoporous graphitic carbon and nitrogen in the supports, compared with 2D graphene without mesopores and mesoporous graphitic carbon supports without nitrogen.

中文翻译：

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在单原子催化剂上合理设计氮掺杂多孔碳载体以实现高效 CO2 电还原


负载在碳 （M–N_x/C） 催化剂上的氮配位单金属原子在电化学 CO₂ 还原反应 （CO₂RR） 中表现出显着的活性。然而，探索载体性质（如形态和电子电导率）与催化活性之间的关系仍然具有挑战性，因为传统的高温热解会在 M-N_x/C 催化剂中诱导多个 M-N_x 配位。在此，制备了一系列具有不同孔径和石墨化程度的氮掺杂多孔碳载体，随后通过锚定 Ni 酞菁 （NiPc） 加载 Ni-N₄ 活性位点。我们发现，载体的电子电导率对于提高低电位区域（从 -0.5 到 -0.7 V_RHE）的 CO 选择性至关重要。然而，受载体形态强烈影响的有效 CO₂ 传输对催化活性的影响比电子电导率更主要。与不含介孔的 2D 石墨烯和不含氮的介孔石墨碳载体相比，由于载体中存在介孔石墨碳和氮，优化后的催化剂表现出出色的 CO₂RR 性能。