Phase engineering of 1 T-MoS2 on BiVO4 photoanode with p–n Junctions: Establishing high speed charges transport channels for efficient photoelectrochemical water splitting

Photoelectrochemical (PEC) conversion of solar energy into chemical energy urgently requires attractive photoelectrodes to advance its practical application. Herein, we demonstrated a simple dopant electron strategy for phase control engineering and prepared a hybrid photoelectrode of 1 T-MoS2 nanosheets sensitized monoclinic BiVO4 (denoted as 1 T-MoS2@BiVO4) with p–n junction. The internal p–n heterojunction in the composite photoanode contributes to its superior charges transport. Further, the inserted 1 T-MoS2 layer at the BiVO4/traditional co-catalysts (OECs) (OECs: FeOOH and NiOOH) interface can profoundly improve the PEC water splitting and solar conversion efficiency of BiVO4-based photoanodes. The corresponding photocurrent density of FeOOH@1T-MoS2@BiVO4 photoelectrode (4.02 mA cm−2) is 3.5 times as high as that of the pure BiVO4 electrode (1.14 mA cm−2) at 1.23 V vs reversible hydrogen electrode (RHE), accompanied by a photoconversion efficiency of 1.28% at 0.68 vs RHE. Theoretical integrated with experimental studies reveal that the insertion of an 1 T-MoS2 layer between BiVO4 and OECs facilitates the establishment of high speed transport channels for holes and electrons. Subsequently, copper phthalocyanine (CuPc) as an unconventional hole-transporting organic material could maintain the photocurrent density of the composite photoanode for stability test over 8 h. Importantly, this study sheds light on the rational design of phase-control-based devices for solar-to-chemical energy conversion, and also implies a prospective nexus between BiVO4 and traditional or unconventional co-catalysts.