Chiral Pd(II) Nanofiber Promoting Electron Transfer of g-C3N4 for Efficient Photocatalytic Hydrogen Production.

Abstract

The rapid transfer and separation of photogenerated electrons is very important for the improvement of photocatalytic efficiency. Here, chiral induced spin selectivity effect (CISS effect) was developed to accelerate electron transfer for efficient photocatalytic hydrogen production. A chiral and achiral racemic supramolecular Pd(II) complex nanofiber was fabricated via supramolecular self-assembly of chiral L-Py or its racemes with Pd(II) and used to modify carbon nitride (g-C₃N₄). The obtained chiral photocatalyst L-Py-Pd/g-C₃N₄-4 and achiral photocatalyst Rac-Pd/g-C₃N₄-4, show enhanced photocatalytic activities with hydrogen evolution rates of 2476 and 1339 μmol g^-1 h^-1, respectively, while that of pure g-C₃N₄ is 30.5 μmol g^-1 h^-1. Chiral photocatalyst has 85 % higher activity than achiral one and is 82.5-fold of pure g-C₃N₄, due to better suppression of the recombination of photogenerated electron-hole pairs in the interface of g-C₃N₄ contact with chiral molecule. Spectral tests and photoelectrochemical tests proved that the chiral supramolecular Pd(II) complex can act both as an electron spin filter and hydrogen reduction catalytic center to enhance photocatalytic efficiency. This work offers a new route to facilitate electron transfer by the CISS effect for photocatalytic hydrogen evolution.