Interface engineering: NiAl-LDH in-situ derived NiP2 quantum dots and Cu3P nanoparticles ingeniously constructed p-n heterojunction for photocatalytic hydrogen evolution

Abstract

The facet-engineered surface and interface design for photocatalytic materials has been proven as a very important approach to construct more advanced photocatalyst for enhancing photocatalytic performance. Here, n-type NiP 2 quantum dots (QDs) as one of mainly active ingredients for efficient hydrogen evolution was derived in situ from the three-dimensional nanoflower NiAl-LDH. The highly ordered nickel node in the NiAl-LDH (parent material) effectively guarantee the high dispersion of NiP 2 QDs derived from the gas-solid reaction. The appearance of NiP 2 QDs not only enriches the active sites but also carries a large number of negatively charged P which can be used as bases to capture more protons and thus accelerate the evolution of hydrogen. In order to directionally regulate carrier migration, the p-n heterojunction was successfully constructed by coupling n-type NiP 2 quantum dots (QDs) and p-type Cu 3 P nanoparticles (NPs). The well-dispersed point-to-point p-n heterojunction hybrid supported on stereoscopic nanoflower structure formed by numerous nanosheets in alternation way exhibits more excellent photocatalytic hydrogen evolution performance due to rich activity sites, large specific surface area, enhanced adsorption on protons and so on. More importantly, the built-in electric field at the interface of p-n junction greatly promotes charge migration and inhibited the recombination of electrons-holes, so the three-dimensional bimetallic phosphide p-n heterojunction, Cu 3 P NPs/NiP 2 QDs, expresses the most prominent photocatalytic hydrogen evolution property compared with alone component. The Cu 3 P/NiP 2 shows excellent hydrogen evolution activity (6783.8 μmol g −1 h −1 ), which is almost 6.6, 8.7 and 30 times than pristine NiAl-P, Cu 3 P and NiAl-LDH, respectively. • Ni species in 3D nanoparticles (NiAl-LDH) are used as “reaction seeds” to derive highly dispersed NiP 2 quantum dots. • NiAl-P exerts a self-supporting effect to induce Cu 3 P nanoparticles to anchor. • Successful construction of p-n heterojunction interface engineering in 3D space system • The built-in electric field of Cu 3 P/NiP 2 p-n heterojunction induces the directional migration of carriers.