Ultrathin Co-Co LDHs nanosheets assembled vertically on MXene: 3D nanoarrays for boosted visible-light-driven CO2 reduction

Converting carbon dioxide (CO2) to multiple energy-rich chemicals by photocatalysis could validly mitigate the severe issues of climate changes and energy shortages. Exploring efficient catalysts for enhancing the performance of CO2 photoreduction is still challenging. Herein, a novel three-dimensional hierarchical Co-Co layered double hydroxide/Ti3C2TX nanosheets (Co-Co LDH/TNS) nanoarray was successfully prepared via an in-situ MOF-derived strategy. This wise design rationally integrates the functional and structural merits of active Co species with conductive MXene to a hierarchical nanoarray architecture composed of ultrathin nanosheets, which can remarkably promote separation of photogenerated charge carriers and accelerate electrons transmission. Benefitting from these features, the hierarchical Co-Co LDH/TNS composites manifest significant enhancement on the CO2-to-CO evolving rate (1.25 × 104 µmol h−1 g−1) under illumination (>400 nm) with a high apparent quantum efficiency (0.92%) and excellent stability. Our work demonstrates that 3D hybrid structure composed of MXene species can serve as promising candidates for CO2 photoreduction, providing fundamental guidance to improve photocatalytic performance by rational engineering of complex hierarchical architecture materials.