Rational design of nanoscale structures can greatly strengthen heterogeneous catalysis with the maximal utilization of active sites. Single atom catalysts (SACs) are recently emerging but a systematic design of nanostructured SAC has rarely been demonstrated yet. Here, distinct architectural structure-dependence of electrochemical CO₂ reduction (CO₂RR) on Ni-based SACs is presented. Starting from Ni-imidazolate coordination polymers (Ni-Im) and their supported counterparts with a carbon nanotube (CNT) and a zeolite imidazolate framework (ZIF-8), the respective derivatives, i.e. Ni-SAC, Ni-SAC-CNT, and Ni-SAC-ZIF8, are obtained after pyrolysis. The presence of substrates ultimately results in large surface porous N-doped carbon nanostructures, which facilitate the diffusion of etchants to remove undesired Ni nanoparticles effectively. The dense Ni single atomic sites contained within the nanostructure are easily accessible to CO₂ reactants during CO₂RR, thus promoting high utilization of active sites even at large current densities. Electro-conductive CNT substrates mediate fluent charge transfer and stimulates the intrinsic activity of catalytic sites. Consequently, operating at 400 mA cm⁻², Ni-SAC-CNT attains a high faradaic efficiency of 99 % toward CO at a low overpotential of 0.24 V, equivalent to a record cathodic energetic efficiency and turnover frequency of 83.4 % and 439,000 h⁻¹, respectively

纳米级结构的合理设计可以在最大限度利用活性位点的情况下大大加强多相催化。单原子催化剂 (SAC) 最近出现，但纳米结构 SAC 的系统设计还很少被证明。在这里，电化学 CO ₂还原（CO ₂RR) 介绍了基于 Ni 的 SAC。从 Ni-咪唑酯配位聚合物 (Ni-Im) 及其带有碳纳米管 (CNT) 和沸石咪唑酯骨架 (ZIF-8) 的对应物开始，各自的衍生物，即 Ni-SAC、Ni-SAC-CNT 和Ni-SAC-ZIF8，在热解后获得。基材的存在最终导致大表面多孔 N 掺杂碳纳米结构，这有助于蚀刻剂的扩散以有效去除不需要的 Ni 纳米颗粒。包含纳米结构内的致密的Ni单原子位点是容易访问的CO ₂中的反应物CO ₂RR，从而即使在大电流密度下也能促进活性位点的高利用率。导电的 CNT 基材介导了流畅的电荷转移并刺激了催化位点的内在活性。因此，在 400 mA cm ^{-2 下}运行时，Ni-SAC-CNT 在 0.24 V 的低过电位下对 CO 实现了 99% 的高法拉第效率，相当于创纪录的 83.4% 和 439,000 h ^{- 的}阴极能量效率和周转频率^{- 1}、分别