Enhanced stability of silicon for photoelectrochemical water oxidation through self-healing enabled by an alkaline protective electrolyte

Abstract

The addition of [Fe(CN)6]3− to alkaline electrolytes impede the corrosion of Si photoanodes at open circuit due to the formation of a SiOx layer.

GaAs Microisland Anodes Protected by Amorphous TiO2 Films Mitigate Corrosion Spreading During Water Oxidation in Alkaline Electrolytes

“…Protective electrolytes can moreover be beneficially used to mitigate corrosion processes in the dark under open-circuit conditions as well as under continuous illumination. 15 The benefits of operating photoanodes under passivating conditions are also demonstrated by the behavior of p + n-InP photoanodes operated at near-neutral pH conditions, under which a passivating oxide forms. Under such conditions, p + n-InP photoanodes protected by NiO x exhibit stable operation for photoanodic O 2 evolution on macroscopically sized electrodes.…”

“…Si photoanodes undergo passivation in alkaline media by formation of Si oxide and, thus, are able to provide extended production of O 2 (g) even if extrinsic defects are present or are formed in the TiO 2 protection layer. Protective electrolytes can moreover be beneficially used to mitigate corrosion processes in the dark under open-circuit conditions as well as under continuous illumination . The benefits of operating photoanodes under passivating conditions are also demonstrated by the behavior of p + n-InP photoanodes operated at near-neutral pH conditions, under which a passivating oxide forms.…”

Deciphering the Electrochemical Behaviors of the Electrode‐Electrolyte Coupling toward Advanced Electrochemical Energy Storage Device

“…Benefiting from the high ionic conductivities of aqueous electrolytes, the electrochemical kinetics can be optimized significantly, resulting in efficient redox reactions with short response time and realizing the higher power density. [ 5,17–18 ] On the other hand, as the additional electrolyte species, there are many redox couples with different reaction potentials that can be chosen in the system, [ 19–20 ] such as Cu 2+ /Cu + , [ 21–22 ] iodine, [ 15,23 ] hydroquinone, [ 24–25 ] and [Fe(CN) 6 ] 4– /[Fe(CN) 6 ] 3– etc., [ 26–28 ] in which the redox reactions can completely proceed even in the limited potential. Therefore, an advanced electrochemical energy storage device with high energy density and power density can be integrated via a synergistic electrode‐electrolyte coupling effect.…”

Enhancing the Long-Term Photoelectrochemical Performance of TiO2/Si Photocathodes by Coating of Ti-Doped Mesoporous Hematite

“…6,7 A strong alkaline electrolyte is favorable for overall water splitting due to the availability of stable, active, and earth-abundant catalysts for the hydrogenevolution reaction (HER) and the oxygen-evolution reaction, as well as the applicability of membrane-free PEC devices. 8 However, Si suffers severe corrosion in alkaline media, which is one of the main issues in the studies of Si-based PEC devices. 9,10 Amorphous TiO 2 is widely applied as a passivation layer to protect Si with good charge conductivity and capability of physical separation for semiconductor materials from the electrolyte.…”

“…Photoelectrochemical (PEC) water splitting is a green technique for production of clean fuel using solar energy. − One of the challenges of this technique is to develop stable and efficient photocathodic devices. , As one of the most promising photocathodic materials, Si possesses an appropriate electronic band structure, high carrier mobility, and ease to build tandem devices. , A strong alkaline electrolyte is favorable for overall water splitting due to the availability of stable, active, and earth-abundant catalysts for the hydrogen-evolution reaction (HER) and the oxygen-evolution reaction, as well as the applicability of membrane-free PEC devices . However, Si suffers severe corrosion in alkaline media, which is one of the main issues in the studies of Si-based PEC devices. , …”