The synergistic Cu⁰-Cu^δ+ sites are found as the active sites for NH₃ synthesis through nitrate electroreduction reaction, but still face significant challenges in stabilizing the Cu^δ+ due to its self-reduction. Here we propose an Ohmic contact interface engineering strategy by loading copper nano-islands on indium hydroxide nanocubes. Attributed to the lower work function of Cu than that of In(OH)₃ with n-type semiconductor nature, the electrons in Cu can transfer unimpededly to In(OH)₃ at the interface of Ohmic junction, triggering and stabilizing polarized Cu⁰-Cu^δ+ active sites. Cu@In(OH)₃ sustains both high NH₃ yield rate (4.28 mmol h⁻¹ mg_cat.⁻¹) and Faradaic efficiency (97.35%) at −0.6 V vs. RHE, while maintaining stability for at least 120 h under an Ampere-level of 800 mA cm⁻². Such Ohmic contact interface engineering approach allows for simultaneously constructing and stabilizing the Cu⁰-Cu^δ+ for the electrosynthesis of ammonia, as well as other value-added chemicals relying on above active sites.

Electrocatalytic reduction of carbon dioxide to produce usable products and fuels such as alkanes, alkenes, and alcohols, is a very promising strategy. Recent experiments have witnessed great advances in precisely controlling the synthesis of single atom alloys (SAAs), which exhibit unique catalytic properties different from alloys and nanoparticles. However, only certain precious metals, such as Pd or Au, can achieve this transformation. Here, the density functional theory (DFT) calculations were performed to show that Zn-based SAAs are promising electrocatalysts for the reduction of CO₂ to C₁ hydrocarbons. We assume that CO₂ reduction in Zn-based SAAs follows a two-step continuous reaction: first Zn reduces CO₂ to CO, and then newly generated CO is captured by M and further reduced to C₁ products such as methane or methanol. This work screens seven stable alloys from 16 SAAs (M = Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, V, Mo, Ti, Cr). Among them, Pd@Zn (101) and Cu@Zn (101) are promising catalysts for CO₂ reduction. The reaction mechanisms of these two SAAs are discussed in detail. Both of them convert CO₂ into methane via the same pathway. They are reduced by the pathway: *CO₂ → *COOH → *CO + H₂O; *CO → *CHO → *CH₂O → *CH₃O → *O + CH₄ → *OH + CH₄ → H₂O + CH₄. However, their potential determination steps are different, i.e., *CO₂ → *COOH (ΔG = 0.70 eV) for Cu@Zn (101) and *CO → *CHO (ΔG = 0.72 eV) for Pd@Zn, respectively. This suggests that Zn-based SAAs can reduce CO₂ to methane with a small overpotential. The solvation effect is simulated by the implicit solvation model, and it is found that H₂O is beneficial to CO₂ reduction. These computational results show an effective monatomic material to form hydrocarbons, which can stimulate experimental efforts to explore the use of SAAs to catalyze CO₂ electrochemical reduction to hydrocarbons.