Metal　single-atom　catalysts　(SACs)　supported　on　carbon　mainly　produce　syngas　in　electrochemical　CO2　reduction　reaction　(CO2RR),　in　comparison　with　the　dominant　H2　production　on　nanoparticles.　However,　it　is　a　major　challenge　to　prepare　the　carbon-supported　SACs　without　the　presence　of　nanopar-ticles　using　conventional　pyrolysis.　Here,　we　report　the　approach　involving　oxygen　etching　at　250　&　DEG;C　to　produce　MOF-derived　nickel/carbon　SAC　(Ni1@C-250A).　The　combination　of　oxygen　etching　with　acid　treatment　completely　removes　the　Ni　nanoparticles,　only　showing　the　existence　of　single-atom　Ni　spe-cies.　In　CO2RR,　the　Ni1@C-250A　exhibits　excellent　faradaic　efficiency　(FE)　of　ti　100%　for　syngas　production　with　the　excellent　stability　for　360　min　time-on-stream.　In　addition,　the　CO/H2　ratio　can　be　adjusted　in　a　wide　range　from　1.5:1　to　4.3:1.　This　approach　involving　oxygen　etching　offers　a　promising　strategy　to　dominantly　produce　SACs　used　for　CO2RR　to　generate　syngas,　which　is　an　important　platform　feedstock　for　the　utilization　of　carbon-based　energy.&　COPY;　2023　Elsevier　Inc.　All　rights　reserved.