NaNbO₃/MoS₂ and NaNbO₃/BiVO₄ Core−Shell Nanostructures for Photoelectrochemical Hydrogen Generation

Abstract

NaNbO3/MoS2 and NaNbO3/BiVO4 core–shell heterostructures show absorption range extending to the visible region and high charge transfer rate at the interface and lower charge recombination which result in overall enhanced photocatalytic activity in the visible region. NaNbO3/MoS2 core–shell heterostructures show higher solar-to-hydrogen conversion efficiency due to better alignment between core and shell interface. The Rct and RIFCT values of NaNbO3/MoS2 core–shell (from EIS studies) are significantly smaller than in NaNbO3/BiVO4 core–shell heterostructures suggesting the charge separation in NaNbO3/MoS2 is more suitable and hence shows higher photocatalytic activity toward photoelectrochemical water splitting and dye degradation. The experimental results were well supported by photoluminescence as well as time-resolved spectroscopy. Enhancement of cathodic current in NaNbO3/MoS2 core–shell heterostructure and from Mott–Schottky plots also indicates appearance of the p–n junction formation between core and shell materials. The p–n junction assists in the separation of photogenerated charge carriers at the core–shell interface. Increasing the negative shift of the flat band potential for the NaNbO3/MoS2 photoelectrode suggested higher charge carrier concentration with reduced charge recombination in comparison with pristine MoS2, BiVO4, and NaNbO3/BiVO4 core–shell heterostructures. The enhanced performance makes these heterostructures ideal candidates for photoelectrochemical hydrogen evolution via water splitting.

Effect of Mn2+ incorporation on the photoelectrochemical properties of BiVO4

“…The position of the valence band (VB) and the conduction band (CB) in a semiconductor plays a crucial role in deciding the charge-transfer properties of the semiconductor. The positions of the VB and CB for all the samples were calculated using the equations given below: 43,44 E VB = X À E 0 + 0.5E g (4)…”

MWCNT modified Ni–Fe LDH/BiVO4 heterojunction: boosted visible-light-driven photoelectrochemical aptasensor for ofloxacin detection

“…The reason is that the noble metal has the ability to increase the separation efficiency of photogenerated carriers and the transfer efficiency of interfacial charge. 21,22…”

Development of Cuboidal KNbO3@α-Fe2O3 Hybrid Nanostructures for Improved Photocatalytic and Photoelectrocatalytic Applications

“…Among the different sources of energy, solar energy is considered as one of the cleanest and environmentally friendly renewable sources of energy that could be used as an alternative to fossil fuels. Different processes like photocatalysis, photoelectrocatalysis, and electrocatalysis are being developed to utilize solar energy in an efficient way for energy generation and environmental remediation. − For fuel production, photoelectrocatalytic (PEC) water splitting is recognized as one of the promising artificial photosynthetic approaches. For PEC water splitting, the light absorption flux of photoanode is suppressed for large-band-gap materials like ZnO, TiO 2 , etc. − The photoelectrocatalytic (PEC) water splitting ability of semiconductor photocatalysts is affected by their band structure and effective separation of charge carriers .…”