File Name : fig. s2.pdf

Caption : fig. s2 characterization of the pure co catalyst. (a) xrd patterns. (b) sem image. (c) tem image. (d) hrtem image.

File Name : fig.s3.pdf

Caption : fig. s3 characterization of the cu5-co5 catalyst. (a-b) sem images. (c-d) tem images.

File Name : fig. s4.pdf

Caption : fig. s4 (a) x-ray photoelectron spectroscopy of the cu5-co5 catalyst. (b) high-resolution of c 1s spectrum of the cu5-co5 catalyst.

File Name : fig. s5.pdf

Caption : fig. s5 lsv curves of (a) cu5-co5, pure cu and co in 1 m koh electrolyte with and without no3−. (b) various ratios of cux-coy catalysts in 1 m koh electrolyte with 0.1 m no3−.

File Name : fig. s6.pdf

Caption : fig. s6 the quantification of nh3, no2−, and n2h4. (a) uv-vis absorption spectra of nh3. (b) the linear standard curve for the calculation of nh3. (c) uv-vis absorption spectra of no2−. (d) the linear standard curve for the calculation of no2−. (e) uv-vis absorption spectra of n2h4. (f) the linear standard curve for the calculation of n2h4.

File Name : fig. s7.pdf

Caption : fig. s7 chronoamperometry curves of the cu5-co5 catalyst at different potentials.

File Name : fig. s8.pdf

Caption : fig. s8 (a) fenh3 of different ratio cux-coy catalysts. (b) the nh3 yield rate of different ratio cux-coy catalysts.

File Name : fig. s9.pdf

Caption : fig. s9 (a) lsv curves of the cu5-co5 and mixed cu5-co5. (b) chronoamperometry curves of the cu5-co5 and mixed cu5-co5 under −0.6 v. (c) nh3 fes and yield rates of cu5-co5 and mixed cu5-co5 under −0.6 v.

File Name : fig. s10.pdf

Caption : fig. s10 (a) lsv curves of the cu5-co5 and cu5co5 alloy. (b) chronoamperometry curves of the cu5-co5 and cu5co5 alloy under −0.6 v. (c) nh3 fes and yield rates of cu5-co5 and cu5co5 alloy catalysts under −0.6 v.

File Name : fig. s11.pdf

Caption : fig. s11 ecsa measurements of (a) cu, (b) co, (c) cu5-co5. the cyclic voltammetry profiles were measured at the sweep rates of 10, 20, 40, 60, 80, 100 mv/s individually.

File Name : fig. s12.pdf

Caption : fig. s12 high-resolution of xps peaks of the catalyst after cycles stability testing (a) cu 2p, (b) co 2p. (c) xrd patterns of the cu5-co5catalyst after no3rr stability test. (d) xrd patterns of the cu5-co5 catalyst after reaction 1 h and 20 h.

File Name : fig. s13.pdf

Caption : fig. s13 schematic illustration of the flow cell equipped with acid capture chamber.

File Name : fig. s14.pdf

Caption : fig. s14 fenh3 of the cu5-co5 catalyst in the flow cell under different current densities.

File Name : fig. s15.pdf

Caption : fig. s15 (a) potential-time curve of the cu5-co5 catalyst in 1 m koh without no3−. (b) uv-vis absorption spectra of nh4+ from the electrolyte after reaction in 1 m koh without no3−. (c) comparison of ion chromatography and indophenol methods.

File Name : fig. s16.pdf

Caption : fig. s16 (a) epr spectra of the cu5-co5 and cu catalysts (collected after 10 min electrolysis at −0.6 v in 1 m koh with no3−). (b) epr spectra of the cu5-co5 and cu catalysts (collected after 10 min electrolysis at −0.6 v in 1 m koh without no3−). (c) time-dependent in-situ atr-seiras spectrums of no3rr on the cu5-co5 catalyst.

File Name : fig. s17.pdf

Caption : fig. s17 in-situ raman spectra measured under 0 v of (a) cu, (b) co and (c) cu5-co5. (d) in-situ raman spectra between of the cu5-co5 catalyst under different potentials.