Ultrathin magnetic Mg-Al LDH photocatalyst for enhanced CO2 reduction: Fabrication and mechanism

The two-dimensional (2D) ultrathin Mg-Al layered double hydroxide modified by magnetic Fe 3 O 4 (Fe 3 O 4 /Mg-Al LDH) was successfully synthesized via the co-precipitation method. The Fe 3 O 4 /Mg-Al LDH not only exhibits superior separation efficiency of charge carriers but also possesses signally enhanced photocatalytic activity for CO 2 reduction than Mg-Al LDH. The as-prepared Fe 3 O 4 /Mg-Al LDH affords the CO and CH 4 generation rate of 442.2 µmol g −1  h −1 and 223.9 µmol g −1  h −1 . The enhanced reduction CO 2 activity mainly comes from synergetic effect of Fe 3 O 4 and ultrathin Mg-Al LDH. And Fe 3 O 4 can increase the separation efficiency of photogenerated electron-hole pairs, and ultrathin Mg-Al LDH can reduce the transmission resistance of charge carriers. Moreover, a detailed mechanism insight of Fe 3 O 4 /Mg-Al LDH for CO 2 reduction is also investigated by a series of characterization methods and activity experiments. This work offers a simple and environment-friendly approach to develop recycled photocatalysts in CO 2 reduction treatment.