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-Bi 2 O 3 to β-Bi 2 O 3 . This phase transition facilitated the development of intrinsic electric field at the interface between V 2 O 5 and β-Bi 2 O 3 , consequently establishing a novel carrier transfer pathway. As a result, the fabricated V 2 O 5 /β-Bi 2 O 3 heterojunction exhibited an outstanding removal efficiency of over 98 % for gaseous mercury (Hg 0 ) 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 V 2 O 5 /β-Bi 2 O 3 heterojunction followed the Z-scheme mechanism. This mechanism significantly contributed to the long-term stability of photocatalytic Hg 0 removal, even when H 2 O 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 Hg 0 in the environment.