A facile method is developed to fabricate nanoporous, structured, Sn-based catalyst electrodes. Sn, Zn, and multiwalled carbon nanotubes (MWCNTs) are co-electrodeposited on a copper substrate, followed by chemical dezincification in NaOH aqueous solution to remove Zn. By controlling variables such as the contents of Zn and MWCNTs, a series of Sn-MWCNT/Cu (SZMC) electrodes are fabricated. Experimental results show that using such novel SZMC electrodes can achieve a HCOO- Faradaic efficiency of over 91% at -0.99 V versus RHE for 10 hours in CO2-saturated 0.5 M KHCO3 aqueous solution. The high performance is attributed to the addition of MWCNTs and Zn, followed by chemical dezincification to remove Zn and then create vacancies in the catalyst structure, which results in a special porous structure of SZMC with large surface area. Then ECSA is used for enhancing the catalytic activity and selectivity of HCOO- production, as well as promoting intermediate adsorption and mass transfer.