C₂N-ring-based molecular chains were designed at the molecular level and theoretically demonstrated to show distinctive and valuable electron transport properties that were superior to the parent carbonaceous system and other similar nanoribbon-based molecular chains. This new -type molecular chain presented an exponential attenuation of the conductance and electron transmission with the length. Essentially, the molecular chain retained the electron-resonant tunneling within 7 nm and the dominant transport orbital was the LUMO. Shorter molecular chains with stronger conductance anomalously possessed a larger tunnel barrier energy, attributing to the compensation of a much smaller HOMO–LUMO gap, and these two internal factors codetermined the transport capacity. Some influencing factors were also studied. In contrast to the common O impurity with a tiny effect on electron transmission of the C₂N rings chain, the common H impurity clearly improved it. When the temperature was less than 400 K, the electron transmission varied with temperature within a narrow range, and the structural disorder deriving from proper heating did not greatly modify the transmission possibility and the exponentially decreasing tendency with the length. In a non-equilibrium condition, the current increased overall with the bias but the growth rate varied with size. A valuable negative differential resistance (NDR) effect appeared in longer molecular chains with an even number of big carbon–nitrogen rings and strengthened with size. The emergence of such an effect originated from the reduction in transmission peaks. The conductance of longer molecular chains was enhanced with the voltage but the two shortest ones presented completely different trends. Applying the bias was demonstrated to be an effective way for C₂N-ring-based molecular chains to slow down the conductance decay constant and affect the transport regime. C₂N-ring-based molecular chains show a perfect application in tunneling diodes and controllable molecular devices.

Electrochemical urea synthesis via co‐reduction of CO ₂ and nitrate (NO ₃ ⁻ ) offers a sustainable route for C─N bond formation but remains challenged by poor selectivity and competing side reactions. Here, we report a dual‐metal interfacial engineering strategy that enables C─N coupling by favoring a key NO─M ₁ ─NO─CO─M ₂ configuration. Using CuBi ₂ O ₄ as a model precursor, in situ electroreduction induces reconstruction into an electron‐enriched and low‐coordinated Cu─Bi interfacial structure. Operando Raman and surface‐enhanced infrared absorption spectroscopy, together with density functional theory calculations, reveal that these reconstructed dual‐metal interfaces enable cooperative adsorption of NO ₃ ⁻ and CO ₂ , favoring a spatially confined NO─Cu─NO─CO─Bi configuration. This proposed configuration lowers the overall activation barrier and converts the traditionally endergonic C─N coupling into an exergonic N─C─N coupling process, thereby redirecting the reaction pathway toward urea formation while suppressing nitrite and CO byproducts. As a result, the catalyst achieves a urea Faradaic efficiency of 32.7% at −0.4 V vs. RHE with a high yield rate of 2955.3 mg h ⁻¹ g ⁻¹ at −0.6 V vs. RHE under large current densities. This work provides insights into a generalizable interfacial‐site design for modulating reaction pathways in electrosynthetic C─N coupling systems.

Dimethylamine borane (DMAB) is a promising solid fuel for borane fuel cells due to its high hydrogen content and safety. However, the development is hindered by electrochemically sluggish DMAB oxidation reaction (DMABOR), since strongly adsorbed hydrogen‐containing reaction intermediates (*H) poison active sites. Herein, a Mo‐single‐atom‐enabled functional‐site‐decoupled PdMo catalyst is developed by combining functional‐site decoupling with atomic‐level oxophilic engineering. Spectroscopy and theoretical studies reveal that the catalyst comprises PdMo alloy particles (APs) and Mo single atoms (SAs), wherein alloyed Mo modulates electronic structure of Pd to weaken *H binding, and Mo SAs act as *OH‐affinitive Lewis‐acid sites that stabilize interfacial *OH, which is proposed to assist the oxidative removal of Pd‐bound *H. Notably, PdMo/KB was applied as the anode in direct DMAB fuel cells (D‐DMABFCs) for the first time, enabling an outstanding peak power density of 1195 mW cm ⁻² and stable operation for over 160 h, highlighting the potential of borane fuel cells as alternatives to hydrogen fuel cells. This functional‐site‐decoupling mechanism is further extended to alkaline hydrogen evolution reaction (HER), enabling a PdMo/KB‐based anion‐exchange membrane water electrolyzer (AEMWE) to reach 1.0 and 2.0 A cm ⁻² at 1.59 and 1.70 V, respectively, and operate stably for 1000 h.