Interfacial engineering of synergistic catalysts is one of the keys to achieving multiple proton‐coupled electron transfer processes in nitrate‐to‐ammonia conversion. Herein, by joining ultrathin nickel‐based metal‐organic framework (denoted Ni‐MOF) nanosheets with few‐layered hydrogen‐substituted graphdiyne‐supported copper single atoms and clusters (denoted HsGDY@Cu), a tandem catalyst of Ni‐MOFs@HsGDY@Cu with dual‐active interfaces was developed for the concerted catalysis of nitrate‐to‐ammonia. In such a system, the sandwiched HsGDY layer could serve as a bridge to connect the coordinated unsaturated Ni2+ sites with Cu single atoms/clusters in a limited range of 0 to 3.6 nm. From Ni2+ to Cu, via the hydrogen spillover process, the hydrogen radicals (H·) generated at the unsaturated Ni2+ sites could migrate across HsGDY to the Cu sites to participate in the transformation of *HNO3 to NH3. From Cu to Ni2+, bypassing the higher reaction energy for *HNO3 formation on the Ni2+ sites, the NO2− detached from the Cu sites could diffuse onto the unsaturated Ni2+ sites to form NH3 as well. The combined results make this hybrid a tandem catalyst with dual active sites for the catalysis of nitrate‐to‐ammonia conversion with improved Faradaic efficiency at lower overpotentials.

中文翻译：

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用 H 取代石墨炔桥接镍-MOF 和铜单原子/团簇用于硝酸盐制氨的串联催化


协同催化剂的界面工程是实现硝酸盐至氨转化中多个质子耦合电子转移过程的关键之一。在此，通过将超薄镍基金属有机骨架（表示为Ni-MOF）纳米片与少层氢取代石墨二炔负载的铜单原子和簇（表示为HsGDY@Cu）连接，形成了Ni-MOF@HsGDY的串联催化剂具有双活性界面的@Cu被开发用于硝酸盐到氨的协同催化。在这样的系统中，夹在中间的HsGDY层可以作为桥梁，在0至3.6 nm的有限范围内将配位不饱和Ni2+位点与Cu单原子/团簇连接起来。从Ni2+到Cu，通过氢溢出过程，不饱和Ni2+位点产生的氢自由基(H·)可以穿过HsGDY迁移到Cu位点，参与*HNO3到NH3的转化。从 Cu 到 Ni2+，绕过 Ni2+ 位点上 *HNO3 形成的较高反应能，从 Cu 位点分离的 NO2− 可以扩散到不饱和 Ni2+ 位点上，也形成 NH3。综合结果使这种混合催化剂成为具有双活性位点的串联催化剂，用于催化硝酸盐至氨的转化，并在较低的过电势下提高了法拉第效率。