ABSTRACT
Skeleton modification on carbon nitride (g-C3N4) via organic molecules is a recognized effective strategy to improve photocatalytic performance because it can powerfully improve charge separation in the skeleton plane. Herein, a diazole with a unique conjugated structure is bonded on edge of the g-C3N4 skeleton through a moderate polymerization of urea with 4-aminoantipyrine (4AAP). Meanwhile, the Pt nanoparticles selectively deposit on edge of the g-C3N4-4AAP15 nanosheet. It reveals that the robust limbic inducted and delocalized effects of diazole not only facilitate photogenerated electrons aggregation toward skeleton edge to promote in-plane carrier separation but also effectively stabilize and delocalize photogenerated electrons to improve carrier lifetime for propelling the photocatalytic hydrogen evolution (PHE) reaction. Specifically, the PHE rate over optimal g-C3N4-4AAP15 (284.2 µmol h-1) is 10 times that of pure g-C3N4 (27.6 µmol h-1) and the apparent quantum efficiency (AQE) at 420 nm reaches up to 24.2%. Through insights into the functionalized effect of small nitrogenous heterocycles introduced into the skeleton edge of g-C3N4, this work opens a new design thought for exploiting high-efficiency g-C3N4-based photocatalysts for photocatalytic application.
ABSTRACT
The application of NiCo-LDHs in the hydrogen evolution reaction (HER) is rarely reported because it is usually served as an effective electrocatalyst for oxygen evolution reaction (OER) owing to the essential chemical and electric structure features. It still is a challenge to realize the effective HER over NiCo-LDHs unless modified with noble metals. In this work, the noble-metal-free core-shell Co(OH)2@P-NiCo-LDH hybrid with dodecahedral hierarchical structure is prepared by the sacrificial template method along with subsequent phosphating process, which is available for the electrocatalytic HER. The fabricated Co(Ni)δ+-Pδ- bonding states on the surface of outer shell NiCo-LDH not only provide the abundant active centers but also reduce interfacial charge transfer resistance to enhance the HER activity. Meanwhile, the unique core-shell dodecahedral structure effectively avoids the agglomeration and restacking of NiCo-LDH nanosheets to improve the electrochemical stability. This work exploits a novel noble-metal-free modification strategy to expand the application of NiCo-LDH in HER.
