X-ray diffraction patterns were collected in the range of 10° ≤ 2θ ≤ 80° on a Panalytical MPD-PRO diffractometer equipped with a linear X'celerator detector with CuKα (1.5406 Å) anode. See Supplementary Note 1 Electrochemistry Analysis and Product Quantification: Electrochemistry experiments were carried out in a home-made gas diffusion electrode (GDE) cell. A modified GDE half cell was used to maximize the sensitivity of the measurements through the use of lower electrolyte volumes. A carbon cloth loaded copper catalysts is sealed in the middle of a sandwiched structure. CO2 molecules can transfer from the bulk gas phase to the gas-liquid boundary layer through the bottom layer (constant 10 mL/min). NH3 was fed through the liquid phase (NH4OH) with different concentrations dissolved in 1 M KOH solution. For a typical electrolysis experiment, 1 mL electrolyte was added into the hydrophobic layer of carbon cloth electrode and saturated with CO2 for at least 5 min. The reference (Ag/AgCl gel in saturated KCl, 25 o C) was used to calculate RHE with ERHE = EAg/AgCl + 0.059 pH + E o Ag/AgCl, where E o Ag/AgCl = 0.206 V. The Ag/AgCl reference was periodically checked against a master reference electrode for any potential drifts to maintain stable in alkaline electrolyte.