Improved photoelectrochemical performance of Z-scheme g-C3N4/Bi2O3/BiPO4 heterostructure and degradation property

In g-C3N4/Bi2O3/BiPO4, the p-n junction between p-type Bi2O3 and n-type BiPO4 was encapsulated by g-C3N4 and a direct Z-scheme was built between g-C3N4 and Bi2O3. The optical, morphological and photoelectrochemical (PEC) properties of BiPO4, g-C3N4/BiPO4, Bi2O3/BiPO4 and g-C3N4/Bi2O3/BiPO4 hierarchical Z-scheme system were studied. More than 90% photodegradation of methyl orange (MO) with the exposure of simulated solar light was achieved within 160 min with the g-C3N4/Bi2O3/BiPO4, which displayed remarkably promoted photocatalytic activities than other samples. The electrochemical impedance spectra and photocurrent results also proved that efficient charge separation and better electron transport properties were achieved by g-C3N4/Bi2O3/BiPO4. In general, the addition of g-C3N4 can guide the residual electrons on p-type Bi2O3 to recombine with photoholes of g-C3N4 and make sure the left carries exhibit stronger oxidation and reduction ability to boost the production of active groups.