Ni 3 B as p-Block Element-Modulated Cocatalyst for Efficient Photocatalytic CO 2 Reduction.

Due to the multiple electron and proton transfer processes involved, the photogenerated charges are easily recombined during the photocatalytic reduction of CO 2 , making the generation of the eight-electron product CH 4 kinetically more difficult. Herein, Ni 3 B nanoparticles modulated by p-block element were combined with TiO 2 nanosheets to construct a novel Schottky junction photocatalyst (Ni 3 B/TiO 2 ) for the selective photocatalytic conversion of CO 2 to CH 4 . The formed Ni 3 B/TiO 2 photocatalyst with Schottky junction ensures a transfer pathway of photogenerated electrons from TiO 2 to Ni 3 B, which facilitates the accumulation of electrons on the surface of Ni 3 B and subsequently improves the activity of photocatalytic CO 2 reduction to CH 4 . The optimized Ni 3 B/TiO 2 Schottky junction shows an improved CH 4 yield of 30.03 μmol g -1 h -1 , which was much higher than those of TiO 2 (1.62 μmol g -1 h -1 ), NiO/TiO 2 (2.44 μmol g -1 h -1 ), and Ni/TiO 2 (4.3 μmol g -1 h -1 ). This work demonstrated that the introduction of p-block elements can alleviate the scaling relationship effect of pure metal cocatalysts to a certain extent, and the modified Ni 3 B can be used as a promising new cocatalyst to effectively improve the selective photocatalytic of CO 2 to CH 4 .