Electrochemically etched triangular pore arrays on GaP and their photoelectrochemical properties from water oxidation

• Large-scale, triangular pore arrays on GaP were obtained via high-field etching.
• The porous GaP exhibited high performance in photoelectrochemical properties.
• The porous structure could enhance photoresponse and facilitate charge separation.
• Significantly enhanced hydrogen production was observed in the porous GaP.

Large-scale, triangular pore arrays on GaP were successfully prepared via a simple and high-efficient approach of electrochemical etching under high field. The obtained ordered porous GaP exhibited high performance in the photoelectrochemical (PEC) properties compared with bulk GaP. The photocurrent of the porous GaP exceeded one order of magnitude higher than that of bulk material under 0.1 V compared to the reversible hydrogen electrode (RHE), which indicated the porous structure could enhance photoresponse and facilitate the separation of photo-induced carrier charges and their collection. The structure of triangular pore arrays cooperated with its depth determined the PEC performance of GaP. The optimal etching depth was obtained via testing the PEC performance. The hydrogen production from bulk GaP and its porous structure material were also tested from water splitting. Upon the porous structure, significantly enhanced hydrogen production has also been observed, which indicated that the porous GaP should have important potential in photocatalytic water splitting.

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