biostudies-literatureXue SMOST | National Natural Science Foundation of China (NSFC)MOST | National Natural Science Foundation of Chinae2319751121https://www.ebi.ac.uk/biostudies/studies/S-EPMC11066983biostudies-literatureUnknown121(18)Defect engineering has been widely applied in semiconductors to improve photocatalytic properties by altering the surface structures. This study is about the transformation of inactive WO₃ nanosheets to a highly effective CO₂-to-CH₄ conversion photocatalyst by introducing surface-ordered defects in abundance. The nonstoichiometric WO_3-<i>x</i> samples were examined by using aberration-corrected electron microscopy. Results unveil abundant surface-ordered terminations derived from the periodic {013} stacking faults with a defect density of 20.2%. The {002} surface-ordered line defects are the active sites for fixation CO₂, transforming the inactive WO₃ nanosheets into a highly active catalyst (CH₄: O₂ = Proceedings of the National Academy of Sciences of the United States of AmericaEnriching surface-ordered defects on WO&lt;sub&gt;3&lt;/sub&gt; for photocatalytic CO&lt;sub&gt;2&lt;/sub&gt;-to-CH&lt;sub&gt;4&lt;/sub&gt; conversion by water.PMC1106698322272024 52222102 51871058 21961142019 22032002 U1905214 21425309Shen MXing WLiang XYu JCWei CLin WWang JYang CHou YXue SWang SWang XYu ZfalseEnriching surface-ordered defects on WO&lt;sub&gt;3&lt;/sub&gt; for photocatalytic CO&lt;sub&gt;2&lt;/sub&gt;-to-CH&lt;sub&gt;4&lt;/sub&gt; conversion by water.Defect engineering has been widely applied in semiconductors to improve photocatalytic properties by altering the surface structures. This study is about the transformation of inactive WO₃ nanosheets to a highly effective CO₂-to-CH₄ conversion photocatalyst by introducing surface-ordered defects in abundance. The nonstoichiometric WO_3-<i>x</i> samples were examined by using aberration-corrected electron microscopy. Results unveil abundant surface-ordered terminations derived from the periodic {013} stacking faults with a defect density of 20.2%. The {002} surface-ordered line defects are the active sites for fixation CO₂, transforming the inactive WO₃ nanosheets into a highly active catalyst (CH₄: O₂ = 2024-01-01T00:00:00Z2024 Apr2025-04-04T03:04:02.845Z2025-04-04T03:04:02.845ZS-EPMC110669833866254810.1073/pnas.2319751121