Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

Abstract

Photoelectrochemical (PEC) water splitting technology is a promising strategy toward producing sustainable hydrogen fuel. However, it is an essential bottleneck to reduce severe charge recombination for the improvement of PEC performance. Construction of heterojunction systems, such as Z-scheme and type II heterojunctions, could efficiently boost charge separation, whereas the mechanism of charge separation is still ambiguous. We describe herein a charge transfer system designed with Bi 2 WO 6 /Bi 2 S 3 (BWO/BS) as a prototype. In this system, Au nanoparticles act as charge relays to engineer a charge transfer pathway, and the obtained BWO/Au/BS photoanode achieves a remarkable photocurrent density of 0.094 mA cm −2 at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 1.2 and 2.3 times larger than those of BWO/BS/Au and BWO, exhibiting long-term photostability. More importantly, scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) studies are performed to in situ-capture the photogenerated hole during the PEC process. Operando analysis reveals that the Zscheme BWO/Au/BS system (1.33 × 10 −2 cm s −1 ) exhibits higher charge transfer kinetics compared to the type II BWO/BS/Au heterostructure (0.85 × 10 −2 cm s −1 ) while efficiently suppressing charge recombination for optimized PEC activity. Note that this smart strategy can also be extended to other semiconductor-based photoanodes such as BiVO 4 . Our study offers an effective pathway for the rational design of highly efficient charge separation for solar conversion based on water splitting.

A photoelectrochemical immunosensor based on magnetic all-solid-state Z-scheme heterojunction for SARS-CoV-2 nucleocapsid protein detection

“…However, as a single photoelectric active component in FST, TiO 2 has the disadvantage of easy recombination of photogenerated electron/hole (e - /h + ). Constructing heterojunction is an effective approach to improve this drawback [17] . Compared with the traditional type-I and type-II heterojunction, the all-solid-state Z-scheme heterojunctions has a unique electrons transfer mode and introduced electron transfer media [18] .…”

Employing bulk-heterostructure conductive polymer PFO/PFBT for the photoelectrochemical analysis of p-phenylenediamine

“…[7][8][9] Subsequently, inorganic heterojunctions are flourishing because appropriate alignment of particular semiconductors may produce enhanced PEC properties. [10][11][12][13] However, the potential leakage of metal ions (e.g., Cd and Pb) from inorganic materials and the severe photocorrosion are still critical concerns for extensive applications. 14,15 Organic semiconductor polymers, with the readily tailored electrical and optical properties, extraordinary light-harvest ability and good stretchability, are a cluster of extensive material for various optoelectronic, for example, light-emitting diodes, field-effect transistors, photovoltaic devices, and organic solar cells.…”

“…7–9 Subsequently, inorganic heterojunctions are flourishing because appropriate alignment of particular semiconductors may produce enhanced PEC properties. 10–13 However, the potential leakage of metal ions ( e.g. , Cd and Pb) from inorganic materials and the severe photocorrosion are still critical concerns for extensive applications.…”

Piezotronic Effect-Assisted Photoelectrochemical Exosomal MicroRNA Monitoring Based on an Electron Donor Self-Supplying Strategy

“…18−20 Therefore, promoting light harvesting and effective separation of photoinduced carriers are placed in the primary position in PEC biosensing systems. 21 Various approaches have been devoted to settle the aforementioned problems within PEC systems, while the bulk charge separation and transfer to the surface have been largely overlooked. 22 Fortunately, the engineering of noncontact external field such as thermal, magnetic, microwave, and ultrasonic fields, which act as an additional impetus to drive charge carrier separation, directional diffusion, and migration, provides an efficient way to solve the aforementioned problems.…”

“…Photoelectrochemical (PEC) bioassay, an emerging and burgeoning technique, has been frequently applied in the field by the analytical community due to its inherent advantages of low background signals, simple operation, low cost, high sensitivity, and easy miniaturization . Generally, the sensitivity of the PEC sensing platform is greatly limited by the light harvesting efficiency and charge separation ability of photoactive materials. − Therefore, promoting light harvesting and effective separation of photoinduced carriers are placed in the primary position in PEC biosensing systems . Various approaches have been devoted to settle the aforementioned problems within PEC systems, while the bulk charge separation and transfer to the surface have been largely overlooked .…”