s Photocatalytic H 2 O 2 production represents a sustainable and promising avenue for energy and environment. Photoproduction of H 2 O 2 in seawater is potentially an alternative to meet the needs of H 2 O 2 utilization in ocean, while with challenges of competitive ions influence and unsolved photocatalytic mechanism. Herein, we constructed a S-scheme heterojunction with the lamellated WO 3 coated CdS semiconductors for photoproduction of H 2 O 2 in actual seawater. Fragmented WO 3 uniformly spread on surface of dispersed CdS spheres by two steps including calcination and ultrasound. Photocatalyst achieved considerable 1.00 mmol·g cat −1 ·h −1 of H 2 O 2 productivity in seawater without electron-proton donors and pure O 2 , 9.3 % of apparent quantum yield (AQY), as well as good reusability. A co-catalysis concept was proposed to explore specific role of ions in seawater on H 2 O 2 photoproduction. S-scheme heterojunction contributed to migration of electrons and holes on interface between WO 3 and CdS, and further promoted separation of photocarriers, and further opened another channel for H 2 O 2 generation. Accumulated electrons in conduction band (CB) of CdS involved in the main route of two-electron reduction of O 2 for H 2 O 2 production, also promoted generation of •O 2 - for opening the auxiliary route. WO 3 /CdS heterojunction provided fundamentals and opportunities for H 2 O 2 production and applications in abundant seawater as a sustainable way.
Jun Wang,Yining Pan,Liangxing Jiang,Min Liu,Fangyang Liu,Ming Jia,Jie Li,Yanqing Lai
Copper ions are not only physiologically essential for life but also hazardous materials causing a series of neurodegenerative diseases. Photoelectrochemical (PEC) detection has attracted a large amount of focus as a potential strategy to develop Cu2+ ion sensors. However, relatively low photocurrent signals with poor antidisturbance ability and the limited concentration range have prevented its practical applications. Here, we designed a WO3/CdS heterojunction photoanode for the PEC determination of Cu2+ in aqueous solution through a simple two-step chemical bath deposition method. The obtained WO3/CdS photoanode had a nanoplate morphology and showed an enhanced photoresponsivity with a photocurrent density of 1.5 mA/cm2 at 1.23 V versus RHE under illumination. Naturally, it exhibited a low detection limit (0.06 μM) and wider range (0.5 μM to 1 mM) for Cu2+ PEC detection first, suggesting that the WO3/CdS heterojunction photoanode is a promising tool to monitor copper pollution in natural environments.
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