Efficient CO₂ photoreduction enabled by the one-dimensional (1D) porous structured NiTiO₃ nanorods

In this study, porous, and hollow nanorods of NiTiO₃ (NiTiO₃ NRs-p: 2–3 μm in length and 400 nm in diameter) are successfully prepared using an ethylene glycol-mediated approach at room temperature (25 °C), followed by calcination at 700 °C in air environment. Their rough surfaces and accumulated holes are advantageous for adsorption and subsequent photoreduction of carbon dioxide (CO₂) under UV–vis irradiation. The NiTiO₃ NRs-p exhibit superior performance in terms of photoconversion of CO₂ (purity 99.999 %, 100 mL/min) into gaseous CO (57.833 μmolg⁻¹ h⁻¹) and CH₄ (24.33 μmolg⁻¹ h⁻¹) with an overall CO₂ selectivity (S_CO2) of 89 %. In contrast, the solid NiTiO₃ nanorods (NiTiO₃ NRs) exhibit moderate performance in CO₂ reduction, producing CO (30.33 μmolg⁻¹ h⁻¹) and CH₄ (11.50 μmolg⁻¹ h⁻¹) with a CO₂ selectivity of S_CO2 = 60 %. NiTiO₃ NRs-p exhibits superior photocatalytic activity against CO₂ over other NiTiO₃ morphologies with similar physical and chemical properties (such as nanoparticles (NPs) and nanofibers (NFs). This enhancement in photocatalytic activity can be attributed to the porous texture and hollow rod-like structure of NiTiO₃ NRs-p, which provides a larger number of active sites to promote rapid mass transport. This unique one-dimensional (1D) structure also facilitates the separation of photogenerated electron-hole pairs, as demonstrated experimentally. This study opens a new room for a simple and facile routes for the photocatalytic conversion of CO₂ into solar fuels.