Fabrication of heterogeneous photocatalysts for insight role of carbon nanofibre in hierarchical WO3/ MoSe2 composite for enhanced photocatalytic hydrogen generation

Abstract

Mimicking the natural photosynthesis system, artificial photocatalysis facilitates effective utilization of solar energy for environmental sustainability and hydrogen energy production. In this work, the robust and efficient carbon fiber has been successfully incorporated into the interface between WO3 nanodots and MoSe2 needles using the facile hydrothermal and solvothermal method. The suitable interfacial contact of heterogeneous photocatalysts plays a significant role in the separation/transfer of interfacial photogenerated electron-hole pairs and hetero-junction. It seems an efficient approach for enhanced photocatalytic performance since the greater area of contact could improve the interfacial rate of charge transfer. The phase structure of prepared WO3 nanodots changed from the monoclinic to hexagonal phase by the addition of co-catalyst. The experimental results exhibited that carbon fiber played a tri-functional role to boost up the photocatalytic activity over MoSe2 nanostructures. It's not only act as operative co-catalyst but could also serve as the conductive electron bridges, rather than general cocatalyst, to accumulate electrons and encourage the hydrogen generation kinetics over the WO3 photocatalysts. More interestingly, the WO3−1% MoSe2−1.5% carbon fiber and WO3−1%MoSe2 nanocomposites demonstrated the excellent rates of hydrogen evolution 438.7 and 356.2 mmol/g.h, which were 7.6 and 6.17 times higher when compared to that of pure MoSe2, respectively. Under the visible light excitation, the atomically junction encourages fast electron transfer from nanofibers to MoSe2 to suppress the rapid recombination kinetics within WO3 nanodots and extend the lifetime of WO3 charge carrier's, thereby releasing more photogenerated electrons with higher reducing power for hydrogen evolution. The current work can contribute with new perspectives and mechanistic insight for the design and development of heterogeneous photocatalysts WO3 based nanostructures using the combination of MoSe2 and trifunctional carbon nanofibers for environment and energy harvesting applications.