Efficient photocatalytic reduction of CO2 by a rhenium-doped TiO2-x/SnO2 inverse opal S-scheme heterostructure assisted by the slow-phonon effect

Light harvesting and carrier separation play significant roles in determining the efficiency of photocatalytic reduction reactions. In this work, rhenium was doped into inverse opal TiO2-x/SnO2 to construct heterojunction catalysts in which Ti3+ is combined with oxygen vacancies (OVs). The slow-photon-effect of the inverse opal (IO) structure and the oxygen deficiency enable the catalysts to have high light-harvesting efficiency. SnO2 was selected to construct the heterojunction, and its excellent electron migration rate was highly beneficial for boosting the separation efficacy of the photogenerated carriers. As a result, the yield of CO in photocatalytic reduction of CO2 using the final obtained catalyst was 16.59 mu mol.g(-1).h- 1, which is approximately 1.21, 2.14 and 7.44 times of the yields obtained using IO-TiO2-x/SnO2, IO-TiO2-x and SnO2, respectively. This strategy, which integrates the slow-photon-effect, oxygen vacancies, and element doping, affords a new avenue for preparing highly active heterojunction photocatalysts and improving photocatalytic performance.

Automated summary

In this study, heterojunction catalysts with high light-harvesting efficiency were constructed using the slow-photon-effect and oxygen deficiency, combined with element doping. The photocatalytic performance for CO2 reduction to CO was greatly improved through the integration of these strategies, achieving significantly higher yields compared to other catalysts.