In Situ Hydrothermal Synthesis of Metallic Bi Self‐Deposited Bi2SiO5 with Enhanced Photocatalytic CO2 Reduction Performance

Abstract

Metal‐modified nanomaterial has been regarded as an effective way to improve its photocatalytic CO2 reduction performance. Herein, metallic Bi self‐doped Bi2SiO5 composites are successfully in situ synthesized via a simple OH−‐assisted hydrothermal controllable route. The experimental results reveal that 2 mol L−1 NaOH plays two roles in the formation of Bi/Bi2SiO5 composites: 1) increasing the specific surface area through cracking the flower‐like microspheres of Bi2SiO5 with the increase of pH value, 57.92 m2 g−1 (pH = 13), 1.54 times as large as pure Bi2SiO5 (pH = 10); 2) dissolving out the different metallic Bi contents by adjusting the volume of 2 mol L−1 NaOH, achieving the optimum metallic Bi content of about 9.01%. Additionally, combined with experimental data and physicochemical characteristics, the novel mechanism of metallic Bi self‐doped bismuth silicate composites is investigated, and an interesting linear relationship between the metallic Bi with the volume of 2 mol L−1 NaOH is confirmed. The Bi/Bi2SiO5 (pH = 13) sample exhibits the highest CO2 photoreduction activity and stability to CO, more than 2.2 times that of pure Bi2SiO5 (pH = 10), which should be mainly attributed to the surface plasmonic resonance effect of metallic Bi, the strong light absorption ability, and the interfacial interaction between metallic Bi and Bi2SiO5.