Efficient visible-light-driven CO2 reduction on Z-scheme Ni(OH)2/CoTiO3 nanocomposites with robust interfacial electric field

Abstract

Visible-light-driven CO₂ conversion into industry-beneficial chemicals is regarded as a sustainable environmental technology. However, its effectiveness was hindered by poor CO₂ adsorption activation and high rates of electron-hole recombination. To address these challenges, novel Z-scheme Ni(OH)₂/CoTiO₃ (NO/CTO) heterostructure photocatalysts are synthesized via a facile chemical precipitation method, which demonstrate significant photocatalytic activity potential under visible light. In this study, the incorporation of Ni(OH)₂ enhances the specific surface area of the photocatalyst, thereby augmenting its CO₂ adsorption capacity. The optimized NO/CTO (0.2NO/CTO) photocatalysts exhibit the highest activity and CO selectivity, with CO production rates and selectivity reaching 10441 μmol·g⁻¹·h⁻¹ and 85.2 %, respectively, which are 4.0 and 5.8 times higher than those of pristine CoTiO₃. In-situ Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFT) analysis reveals effective CO₂ adsorption on the NO/CTO surface and the formation mechanism of intermediates in the reaction. X-ray photoelectron spectroscopy (XPS) analysis indicates strong electronic coupling between Ni(OH)₂ and CoTiO₃. Density Functional Theory (DFT) simulations further elucidate the generation of interfacial electric field (IEF), facilitating the formation of an effective Z-scheme heterojunction. This study provides a promising strategy to produce low-cost transition metal based nanocomposites for efficient CO₂ photoreduction.