Photothermal assisted CO2 photoreduction over hollow urchin-like structured TiO2@SnS2 heterojunction with enriched oxygen defects

Abstract

Solar driving CO₂ photoreduction represents a highly promising strategy that can not only reduce CO₂ level in the atmosphere but also yield value-added chemicals. Herein, an urchin-like hollow structured hybrid with TiO₂@SnS₂ heterogeneous junction was designed and synthesized through a facile approach including hard-template method and hydrothermal process. When used as catalyst for photocatalytic CO₂ reduction, the optimized sample exhibited exceptional activity with a CO yield rate of 52.86 µmol·g^-1h⁻¹ and durability during 4 cycles within 28 h. The enhanced performance could be attributed to i) the confinement effect of hollow structure enhancing the light capture and absorption owing to the multi-reflection/scattering of incident light in hollow cavity; ii) the constructed hetero-junction between TiO₂ and SnS₂ facilitating the transfer and separation of charge carriers and iii) photothermal effect induced by confinement effect of hollow structure through trapping the unused incident light and oxygen defects promoting the activation of CO₂ molecules. We believed that this work could inspire further development in the field of synthesis of hollow structured catalysts as well as photocatalysis.