Effect of microstructure and reaction medium on photocatalytic performance and stability of BiO catalyst for CO2 reduction

Control the microstructure of the photocatalyst and change the reaction medium have great potential to improve activity and selectivity of a photocatalyst. Herein, we prepared ordered mesoporous and quantum dot BiO with similar grain size, and then studied their CO2 reduction performance under different reaction mediums. The results revealed that the activity, selectivity and stability of a photocatalyst are importantly influenced by reaction medium and microstructure of a photocatalyst. Under the same conditions, quantum dot BiO exhibited higher activity but much lower stability than mesoporous structure. More importantly, it was found gas-solid reaction are more efficient than liquid-solid reaction mode. [Display omitted] •Ordered mesoprous BiO catalyst was firstly constructed for CO2 reduction.•Gas-solid reaction is superior than liquid-solid both in selectivity and activity.•CO selectivity from CO2 photoreduction is over 99% in gas-solid mode.•This study clearly revealed the reaction pathways for CO2 reduction.