Copper containing 3D polyaniline/phytic acid hydrogels for photocatalytic hydrogen production

Abstract A Cu-PP hydrogel with 3D network was synthesized using a simple in-situ polymerization method. PA (phytic acid) acts as the dopants and crosslinking agent to form PANI-PA (polyaniline-phytic acid) hydrogel via in-situ polymerization of aniline. PA is also used as a chelating agent to coordinate with Cu 2+ ion due to the high coordination capacity. When irradiated by light, Cu 2+ was slowly reduced to form Cu NPs, distributing uniformly in the 3D matrix of PANI-PA. The 3D network nanostructure ensures a complete contact between the photocatalyst and water, promoting the separation of electrons and holes. The introduction of PANI-PA improves the separation efficiency of electron-hole pairs, where PANI-PA acts as a hole reservoir to trap the holes generated by Cu NPs, hindering the recombination of electron-hole pairs. The Cu 0.2 -PP hydrogel with a copper content of 30.8% exhibits the best hydrogen production rate (6.09 mmol·g −1 ·h −1 ), which is 6.7 times greater than that of pure Cu NPs. Graphical abstract