Bismuth Vanadate Photoelectrodes with High Photovoltage as Photoanode and Photocathode in Photoelectrochemical Cells for Water Splitting

Abstract

Using dual-photoelectrode photoelectrochemical (PEC) devices based on earth-abundant metal oxides for unbiased water splitting is an attractive means of producing green H fuel, but is challenging, owing to low photovoltages generated by PEC cells. This problem can be solved by coupling n-type BiVO with n-type Bi V O to create a virtual p/n junction due to the formation of a hole-inversion layer at the semiconductor interface. Thus, photoelectrodes with high photovoltage outputs were synthesized. The photoelectrodes exhibited features of p- and n-type semiconductors when illuminated under an applied bias, suggesting their use as photoanode and photocathode in a dual-photoelectrode PEC cell. This concept was proved by connecting a 1 mol % W-doped BiVO /Bi V O photoanode with an undoped BiVO /Bi V O photocathode, which produced a high photovoltage of 1.54 V, sufficient to drive stand-alone water splitting with 0.95 % efficiency.

A nanostructured NiO/cubic SiC p–n heterojunction photoanode for enhanced solar water splitting

“…The 3C-SiC/NiO photoanode demonstrates a maximum ABPE of 0.69% at 0.55 V RHE , which is the highest photoconversion efficiency among those reported for SiC-based photoanodes. 44 As a comparison, the 3C-SiC photoanode shows a much lower maximum ABPE of 0.035% at a higher potential of 0.85 V RHE . Notably, the 3C-SiC/ NiO heterojunction photoanode not only increases the conversion efficiency but also reduces the required potential to reach the maximum photoconversion efficiency.…”

Photoelectrochemical water splitting by hybrid organic-inorganic systems: Setting the path from 2% to 20% solar-to-hydrogen conversion efficiency

“…To pursue the goal of a PEC-water-splitting (WS) system with appreciable STH efficiency, lots of efforts have been dedicated to the design and optimization of two-photoelectrode systems, while several techno-economic analysis addressed the forecasted scenario in terms of cost, efficiency, and service-life balance to make this technology viable on a large scale ( Pinaud et al., 2013 ; Sathre et al., 2014 ; Shaner et al., 2016 ). Throughout the years, inorganic materials—mainly oxides—have been thoroughly investigated, but results lagged behind expectations with a yield of less than 1% STH for full PEC tandem system ( Bornoz et al., 2014 ; Chen et al., 2018a ; dos Santos et al., 2018 ; Xu et al., 2016 ).…”

Screen printed carbon CsPbBr3 solar cells with high open-circuit photovoltage

“…High voltage solar cells are essential for a variety of applications, such as charging low-power electronic batteries, 28 indoor applications and photoelectrochemical unassisted water splitting. 29 Most perovskite devices use methylammonium (MA) and formamidinium (FA) as organic cations. Another limitation in the commercialisation of organo-lead halide perovskites is their thermal and moisture instability.…”