Phase transition guided V2O5/β-Bi2O3 Z-scheme heterojunctions for efficient photocatalytic Hg0 oxidation

The incorporation of vanadium during the synthesis process induced a spontaneous and complete thermal phase transition from α-Bi2O3 to β-Bi2O3. This phase transition facilitated the development of intrinsic electric field at the interface between V2O5 and β-Bi2O3, consequently establishing a novel carrier transfer pathway. As a result, the fabricated V2O5/β-Bi2O3 heterojunction exhibited an outstanding removal efficiency of over 98 % for gaseous mercury (Hg0) under UV light, and this efficiency of 95.0 % even after 35 h of testing. Introducing vanadium enhanced the light absorption capacity in the ultraviolet region and effectively separated photoinduced charge carriers. As revealed by density functional theory calculations, the photoinduced electron–hole transfer in the V2O5/β-Bi2O3 heterojunction followed the Z-scheme mechanism. This mechanism significantly contributed to the long-term stability of photocatalytic Hg0 removal, even when H2O and NO were present. This study presents a novel material composited by a thermal phase transition technique, aimed at the highly effective and green removal of Hg0 in the environment.