In Situ Growth of FeNi-LDHs on Fe۲Ni-MOFs for fabrication of “p–n” heterojunction with enhanced separation of charge carriers for highly efficient photocatalytic H۲ evolution

Hydrogen evolution from water can be an effective strategy to deal with the energy crisis in the current conditions, where the shortage of energy and environmental pollution have challenged the world.[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.