Boosting photocatalytic CO2 reduction via Schottky junction with ZnCr layered double hydroxide nanoflakes aggregated on 2D Ti3C2Tx cocatalyst

Abstract

Designing efficient photocatalysts is vital for the photoreduction of CO₂ to produce solar fuels, helping to alleviate issues of fossil fuel depletion and global warming. In this work, a novel ZnCr-LDH/Ti₃C₂T_x Schottky junction is successfully synthesized using an in situ coprecipitation method. ZnCr-LDH nanoflakes collectively grow on the surface of Ti₃C₂T_x MXene nanosheets. When using Ti₃C₂T_x MXene as a cocatalyst in the prepared heterojunction, the light absorption intensity, photo-induced electron separation and migration efficiency increase. As a result, the composite ZnCr-LDH/Ti₃C₂T_x results in significant improvement in the performance of photocatalytic CO₂ reduction under simulated solar irradiation. The optimized sample ZCTC25 has the highest photocatalytic CO₂ reduction rates of 122.45 μmol g⁻¹ CO and 19.95 μmol g⁻¹ CH₄ (after 6 h of irradiation). These values are approximately 2.65 times higher than those of pristine ZnCr-LDH. The product selectivity towards CO is 86%. This work provides a new method for the construction of novel 2D semiconductor photocatalysts and enriches the application of an unusual type of layered double hydroxides in the photoreduction of CO₂.