Subsurface Mo Vacancy in Bismuth Molybdate Promotes Photocatalytic Oxidation of Lactate to Pyruvate

Abstract

Disclosing the role of subsurface metal defects in photocatalysts remains challenging, although defect engineering has been a fundamental method for manipulating the photocatalytic transformation performance. Herein, the subsurface Mo vacancy-rich Bi 2 MoO 6 was prepared and the role of its effects on photocatalysis was revealed. The presence of metal vacancy enhances the separation efficiency of photogenerated carriers through both the holes captured by the oxygen atoms neighboring the Mo vacancy and the generation of an internal electric field, which is revealed by experimental results and density functional theory calculations. The boosted separation efficiency of electron−hole pairs improves the generation of 1 O 2 , which is the final active species for photocatalytic oxidation of ethyl lactate. The conversion of ethyl lactate reaches to >99% over the subsurface Mo vacancy-rich Bi 2 MoO 6 after 3 h of illumination, much higher than that of bulk Bi 2 MoO 6 , which gives only 28.6%. Meanwhile, the yield of ethyl pyruvate is 90.2%, which is the highest value in heterogeneous systems using molecular oxygen as oxidant. Moreover, the catalyst is rather stable and can be applied for the selective oxidation of other hydroxyl compounds. This work unveils the role of metal defects engineering in affecting electron−hole separation, highlighting possible opportunities for highly efficient photocatalytic organic transformation.

Transformation of a Polyoxometalate Precursor into Carbon Doped Bismuth Molybdate Nanosheets for the Visible Light Photocatalytic Degradation of Aqueous Pollutants

“…Furthermore, the TEM analyses confirmed that the U-BMO nanosheets are larger than those of C-BMO, as observed in FESEM analyses. The HRTEM analysis of U-BMO showed lattice fringes of 0.270 nm dimension corresponding to the (002) plane of Bi 2 MoO 6 (see Figure c, marked in the yellow area), and the inset shows the FFT (Figure d) and IFFT (Figure e) images processed from the same selected area. The similar lattice fringes obtained for C-BMO also correspond to the (002) plane of Bi 2 MoO 6 with a slight increase in its dimension to 0.271 nm (see Figure j), which can be correlated to the expansion of the crystal lattice upon carbon doping .…”

Directional Electron Transfer in CuInS2/Mo2S3 S-Scheme Heterojunctions for Efficient Photocatalytic Hydrogen Production

“…Among catalytic materials, two-dimensional Mo 2 S 3 nanosheets exhibit intriguing optical and electrical properties . However, the positions of the conduction band (CB) and valence band (VB) of metal sulfide are inappropriate, which under light conditions do not provide enough driving force for the hydrogen evolution reaction during the catalytic reaction, resulting in the recombination of photogenerated carriers. , However, the incorporation of a transition metal into molybdenum-based sulfides to form heterojunctions can optimize the electronic structure of molybdenum-based sulfides, making it an effective method for improving the hydrogen evolution activity of photocatalysts. , …”