Engineered controlled on the synthesis of bismuth-molybdenum oxide semiconductors tailors photoelectrocatalytic activity

Aranda-Aguirre A.; Valdivia-Alvarez D.; Pastrana E.C.; Garcia-Segura S.; Cerrón-Calle G.A.; Alarcon H. · Journal of Electroanalytical Chemistry (2025) · DOI: 10.1016/j.jelechem.2025.118956

Resumen

The engineered fabrication of Bi2MoO6 thin-films enables controlled modification of photoelectrocatalytic responses based on the synthesis method. Using a modified Pechini auto-combustion method, which involves the formation of stable chelates between mixed metal ions and citric acid, the photoelectrochemical performance of Bi2MoO6 can be tuned by varying the synthesis components. This study elucidates the impacts of HNO3, NH3, and Bi3+ concentrations during the manufacturing of Bi2MoO6 thin layers. The concentration of HNO3 was critical for the formation of a high-purity crystallographic phase. Adding NH3 enhanced photoelectrochemical responses due to its thermal effect during combustion, resulting from crosslinking between metal-citrate complexes. Additionally, the photocurrent response under applied potential and light irradiation (λ = 365 nm) could be tuned by adjusting the stoichiometry between Bi3+ and Mo6+. The optimal Bi3+:Mo6+ ratio resulted in the maximum photocurrent of 0.65 mA cm-2 at 0.61 V vs Ag/AgCl (1.23 V vs RHE) and lowest charge transfer resistance value of 0.8 kΩ when evaluated in the presence of hole-scavenger species. This study provides an understanding into the role of each synthesis component and highlights the importance of optimizing synthesis procedures to achieve higher photoelectrochemical performance in thin-film catalysts.

Instituciones: Universidad Nacional de Ingeniería