Carbon dots enhanced interfacial electron storage and transfer of iron phosphide for productively photocatalytic water splitting

Abstract

Iron phosphide (FeP), as a low-cost and high-performance phosphide, not only has good stability but also possesses broad optical absorption, which can be used as a visible light or even near-infrared photocatalyst. However, their limited photocatalytic performance arises from the rapid charge recombination and a scarcity of active sites. Here, FeP was modified by introducing carbon dots (CDs), and the photocatalytic performance for H2 production of CDs/FeP reached 33.85 μmol/h/g, which improved significantly compared to that of the pristine FeP (6.65 μmol/h/g). The catalytic reaction goes through a 4-electron passway, which generates O2 and H2 simultaneously. CDs can not merely accelerate the interfacial charge delivery rate, but also can rapidly store photogenerated electrons, reducing the recombination of electrons and holes to improve the photocatalytic performance of FeP. This work provides a new perspective on enhancing the photocatalytic water activity of phosphides by improving electron transfer at the phosphide interface.