Synthesis of bismuth molybdate photocatalysts for CO2 photo-reduction

To explore the possibilities of bismuth molybdate in CO2 photo-reduction to chemicals and fuels, two types of bismuth molybdate namely Bi2MoO6 and Bi3.64Mo0.36O6.55 were synthesized via hydrothermal treatment by adjusting the pH of reaction solution. Bi2MoO6 is constituted by MoO6 octahedra while Bi3.64Mo0.36O6.55 is constructed by MoO4 tetrahedra. Different structure causes quite different properties, like electron binding energy, photoluminescence character, band edge position, optical and electrochemical properties. Comprehensively speaking, Bi2MoO6 made the most of solar energy and showed relatively more efficient charge migration and separation efficiency, contributing to its higher activity for CO2 photo-reduction. After irradiating for 5 h, the yields of CO gas over the both samples were 85.5172 (Bi2MoO6) and 57.3259 (Bi3.64Mo0.36O6.55) μmol/g, respectively. Last, the photocatalytic reduction mechanism was analyzed.