Photocatalytic H۲ Evolution on Fe۲Ni Metal-Organic Framework/Fe-Ni Layered Double Hydroxide Nanocomposites under Visible Light Irradiation

It is highly desirable but challenging to optimize the electronic structure of an active site to realize moderate active site-Hads bond energies for boosting photocatalytic H۲ evolution.[۱] The hydrogen evolution rates of photocatalysts suffer from weak oxidation and reduction ability and low photogenerated charge carrier separation efficiency. Robust and highly efficient p–n heterojunction photocatalysts have a striking ability to enhance light-harvesting capacity and retard the recombination of photoexcitons.[۲] Metal-organic frameworks (MOFs) are emerging potential photocatalysts due to their structural adaptability, porous configuration, several active sites, and wide range of performance.[۳] Nevertheless, there are still limitations in the MOFs photocatalytic H۲ evolution reaction with the higher charge recombination rates. Firstly, a series of FeNi-LDH@Fe۲Ni-MOF heterojunction composites with different FeNi-LDH contents have been synthesized. In the synthesis protocol highly dispersed FeNi-LDH provided more active edge sites for the growth of Fe۲Ni-MOF, leading to a hierarchical architecture with intimate interfacial contact. Under light irradiation, FeNi-LDH@Fe۲Ni-MOF composites hold a remarkable average H۲ evolution rate better than those of pristine FeNi-LDH and Fe۲Ni-MOF. This superior photocatalyic activity is due to the efficient separation of electron–hole charge carriers at the interface, as supported by a photoluminescence study and EIS measurements.

کلیدواژه ها:

Metal–organic framework ، Layered double hydroxides ، Hydrogen evolution ، “p–n” heterojunction.