For high reactivity but poor stability of homogeneous metal complexes in CO₂ photoreduction, development of durable systems is still a big challenge. Herein, pentanuclear Co(II) complex [Co₅(btz)₆(NO₃)₄(H₂O)₄] (1, btz = benzotriazolate) is explored for converting CO₂ to syngas which shows high stability and reactivity in both pure and diluted CO₂. Compared with mononuclear structure, multinuclear complex exhibits 212-fold enhancement in reactivity, up to ~2748 TONs, with wide adjustability of H₂/CO ratio from 16:1 to 2:1. This reactivity could be maintained over 200 h which is an order of magnitude higher than the durability of mononuclear complex and exceeds most reported homogeneous molecular catalysts. High reactivity is also achieved in extreme low CO₂ content (5%). Structural analysis and density functional theory (DFT) calculations support that multinuclear structure and the low energy barrier for photocatalytic intermediate may account for the durable and efficient performance of complex 1. The multinuclear strategy is also adopted to nickel complex. This work probes origin of metal-node-dependent performance for CO₂ photoreduction, providing new insights in design of durable and efficient metal complexes for photocatalysis and other applications.

对于高反应性但均相金属配合物在CO _2光还原中稳定性差的问题，开发耐用的系统仍然是一个巨大的挑战。在本文中，探索了_五核Co（II）配合物[Co ₅（btz）₆（NO ₃）₄（H ₂ O）₄ ]（1，btz =苯并三唑酸酯）将CO ₂转化为合成气，该合成气在两个方面均显示出高稳定性和反应性纯净和稀释的CO ₂。与单核结构相比，多核复合物的反应性提高了212倍，最高可达〜2748 TONs，并且H _2的可调节性广/ CO比从16：1到2：1。该反应性可以维持超过200小时，这比单核络合物的耐久性要高一个数量级，并且超过大多数报道的均相分子催化剂。在极低的CO ₂含量（5％）下也可实现高反应性。结构分析和密度泛函理论（DFT）计算表明，多核结构和光催化中间体的低能垒可能是配合物1持久且高效的性能。镍配合物也采用了多核策略。这项工作探索了CO _2光还原过程中依赖于金属节点的性能的起源，为设计用于光催化和其他应用的耐用高效金属络合物提供了新的见解。