Proximity of defects and Ti-H on hydrogenated SrTiO3 mediated photocatalytic reduction of CO2 to C2H2

Photocatalytic converting CO2 into C2 products is highly desirable but is extremely sensitive to catalyst structure. In this work, Ti-H species and oxygen vacancies are simultaneously integrated on hydrogenated SrTiO3 surface by thermally treating with NaBH4, which promotes the activation of CO2 into HCOO- and CO* intermediates. The proximity of oxygen vacancies and Ti-H species contributes to the C-C coupling of intermediates into acetylene (C2H2) products. To the best of our knowledge, this is the first example for the photocatalytic CO2 reduction into C2H2 main products. The optimal hydrogenated SrTiO3 has the C2H2 yield of 39.0 μmol·g−1 with a 76.0 % selectivity among C2 products. Therefore, this work provides an approach of designing the adjacent active sites for photocatalytic CO2 conversion into C2+ products.