Enhancement of photocatalytic activity for BiPO4 via phase junction

BiPO4 with a phase junction was synthesized by calcinating hexagonal BiPO4(HBIP) at different temperatures. The phase structures of BiPO4 were gradually transformed from HBIP to monazite monoclinic BiPO4 (nMBIP) and monoclinic BiPO4 (mMBIP) with increasing calcination temperature. The enhancement of the photocatalytic performance and photocurrent were ascribed to the formation of phase junction. A nMBIP-mMBIP surface-phase junction was formed in BIPO4 when HBIP was calcined at 500 C degrees, and its photocatalytic activity was 28.7 times as high as that of HBIP. Moreover, radical trapping experiments confirmed that the hole was the active species for BiPO4 on the degradation of methylene blue.