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利用可再生能源产生的电能催化二氧化碳还原(CO2RR)是可持续制备碳基化学品的一种潜在途径.电催化剂是实现这个转化的关键,目前还需要深入地研究机理去优化催化剂的设计.M-N4结构的大环配合物是一类结构明确、性能易调控的分子电催化剂,是研究结构-性能关系的理想平台.其中,金属酞菁在异相电催化CO2RR中展现出较好的催化性能,受到广泛关注.而其它M-N4结构大环配合物(如金属卟啉、金属咔咯)在异相电催化CO2RR中报道较少,且催化性能一般.本文对比研究了酞菁钴(CoPc)、四苯基卟啉钴(CoTPP)和三苯基咔咯钴(CoTPC)三种分子异相电催化CO2RR的性能,揭示制约金属卟啉和金属咔咯分子应用于异相体系的原因,并提出改进方法.首先采用碳纳米管(CNT)复合的方法对三种分子进行了研究.结果表明,只有CoPc能够与CNT形成性能优异的复合电催化剂,而CoTPP和CoTPC复合电催化剂几乎不具备活性.这是因为这两种分子具有扭曲的苯环导致分子与CNT作用力弱,在复合物里面只有很少的分子锚定在CNT上.本文采用直接滴涂法制备三种分子与CNT物理混合电极,并研究了分子载量对催化性能的影响.结果表明,在1.08×10-8 mol cm-2低分子载量时,CoTPP+CNT和CoTPC+CNT样品基本无活性,它们的电催化活性随着分子载量的提升而显著增加.在5.4×10-7 mol cm-2的高载量时,CoTPC+CNT和CoTPP+CNT样品在-0.67 V(相对可逆氢电极,下同)的电位下分别展现出14.0和7.61 mA cm-2的CO分电流密度,是1.08×10-8 mol cm-2载量样品的8.7和7.9倍.这说明对于CoTPP和CoTPC分子,可以通过加大载量来增加与CNT作用几率,从而提高电极活性.然而,基于CoPc制备的样品活性随着CoPc分子载量的增加变化不明显.这是由于在低载量下CoPc分子已经很好地与CNT相互作用,并且CNT上CoPc分子负载量是有限的,继续增大载量只会导致聚集.本文进一步发展一种聚乙烯吡啶(PVP)桥连的办法,提升CoTPP和CoTPC在低载量下的电极活性.聚乙烯链能够通过疏水作用缠绕在CNT上,同时吡啶能够与分子金属中心配位,从而为分子与CNT结合建立桥梁.当分子载量为1.08×10-8 mol cm-2时,CoTPP+CNT/PVP在-0.67 V电位下展现出85％以上的CO法拉第效率,而且CO分电流密度达到7.84 mA cm-2,是没有添加PVP对比样CoTPP+CNT的8倍.由此可见,分子与基底的相互作用强度对异相电催化CO2RR的性能有重要影响.对于与基底相互作用弱的大环配合物分子可以通过大分子载量的滴涂法或引入桥连分子来提高电极性能.这些方法可以拓展到其它分子体系,有助于构建高效的异相分子电催化剂.“,”Metal-N4 (M-N4) macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning. Among them, metal phthalocyanines have been widely stud-ied for the carbon dioxide reduction reaction (CO2RR) in heterogeneous systems and demonstrated good electrocatalytic performance. However, other complexes like metal corroles and metal por-phyrins are much less explored, and often show inferior performances. In this study, three cobalt macrocyclic complexes, cobalt phthalocyanine, cobalt meso-tetraphenylporphyrin, and cobalt me-so-triphenylcorrole (CoPc, CoTPP and CoTPC) are investigated in heterogeneous electrocatalysis of CO2RR. Although CoPc/carbon nanotube (CNT) hybrid exhibits high electrocatalytic activity, CNT hybridization does not work for CoTPC and CoTPP that hold weak interactions with CNTs. By the drop-dry method with a high molecular loading of 5.4 × 10-7 mol cm-2, CoTPC and CoTPP could deliver appreciable electrode activities. Poly(4-vinylpyridine) (PVP) introduction is further demon-strated as a facile method to afford enhanced activities for CoTPP at low molecular loadings through enhancing molecule-substrate interactions. The partial current density of carbon monoxide for CoTPP+CNT/PVP is around 8 times higher than the sample without PVP at -0.67 V versus reversi-ble hydrogen electrode. This work provides solutions to enhance the electrode activities of molecu-lar electrocatalysts with weak substrate interactions in heterogeneous systems.