Heterojunction g-C3N4/CeO2/Bi2O3 composite for the photocatalytic purification of exhaust gas

This work describes the preparation of g-C3N4/CeO2/Bi2O3 ternary heterojunction composite photocatalytic materials. The preparation of the sample was optimized via adjustments to the mass mix ratio. The crystal structure, morphological characteristics, and optical properties of the samples were investigated. The results show that the sample with a 3:4:14.55 mass ratio of g-C3N4, CeO2, and Bi (NO3)3·5H2O has the highest purification efficiency for exhaust pollutants. Ce–O–Bi bonds were found based on the microscopic characterization tests. The band gap value of g-C3N4/CeO2/Bi2O3 decreased, which indicate that multilayer heterojunction could resolve the problem of photocatalyst carrier separation. The purification efficiency for HC, CO, CO2, and NOX within 60 min was measured as 19.7%, 14.7%, 12.6%, and 42.96%, respectively, under visible light irradiation. Furthermore, g-C3N4/CeO2/Bi2O3 self-cleaning coatings were prepared. Under natural light irradiation, the purification efficiencies for HC, CO, CO2, and NOX were 16.86%, 12.22%, 10.88%, and 40.29%, respectively. This work provides a new method for use in future exhaust treatment and carbon neutral research. •g-C3N4/CeO2/Bi2O3 strengthens photocatalyst carrier separation.•g-C3N4/CeO2/Bi2O3 exhibits a strong exhaust gas purification effect.•g-C3N4/CeO2/Bi2O3 self-cleaning coatings were prepared.•Self-cleaning coatings can degrade exhaust pollutants.•We present a new method through which to solve air pollution.