Z-scheme Fe2(MoO4)3/Ag/Ag3PO4 heterojunction with enhanced degradation rate by in-situ generated H2O2: Turning waste (H2O2) into wealth (•OH).

By taking advantage of in-situ generated H 2 O 2 , Z-scheme Fe 2 (MoO 4) 3 /Ag/Ag 3 PO 4 heterojunction displayed outstanding degradation performance. [Display omitted] • Internal-electric-field is built at interface, resulting in a Z-scheme routine of e - • k of Fe 2 (MoO 4) 3 /Ag/Ag 3 PO 4 is 254 and 7.0 times than those of Fe 2 (MoO 4) 3 and Ag 3 PO 4. • H 2 O 2 is activated on Fe 2 (MoO 4) 3 for •OH, avoiding quenching effect on h + and e - • k is improved by 1.7 times via turning waste (H 2 O 2) into wealth (•OH) • 91.2% of removal efficiency is remained after 5 runs, while that of Ag 3 PO 4 is 68.1% Ag 3 PO 4 -based photocatalysts have been deeply studied in environmental remediation; however, two problems limited their further application: photocorrosion and quenching effect by in-situ generated H 2 O 2. To addressed these two questions simultaneously, Fe 2 (MoO 4) 3 was coupled with Ag 3 PO 4 to construct Z-scheme Fe 2 (MoO 4) 3 /Ag/Ag 3 PO 4 heterojunction driven by internal-electric-field. The rhodamine B degradation rate of heterojunction was 254 and 7.0 times higher than those of Fe 2 (MoO 4) 3 and Ag 3 PO 4 , respectively. The outstanding photoactivity was due to the high visible-light harvest, low interface resistance, high separation efficiency of charge carriers, long lifetime of hole (h +) and electron (e -), well-preserved oxidation potential of h +, and especially photocatalytic produced H 2 O 2 inside the system. The in-situ generated H 2 O 2 was fully activated to be •OH on the Fe 2 (MoO 4) 3 surface via a Fenton reaction, leading to the elimination of quenching effect on h + and e -, and generation of more •OH. Additionally, in Z-scheme heterojunction, e - transferred from Ag 3 PO 4 to Fe 2 (MoO 4) 3 , avoiding the accumulation on Ag 3 PO 4 surface, and hence suppressing the photocorrosion. As a result, 91.2% of degradation efficiency remained after 5 cycles. This paper provides a new method to simultaneously increase the degradation rate by utilizing the in-situ generated H 2 O 2 and improve the stability of Ag 3 PO 4 via constructing a Z-scheme heterojunction. [ABSTRACT FROM AUTHOR]