Promoting Visible Light Generation of Hydrogen Using a Sol-Gel-Prepared MnCoO@g-CN p-n Heterojunction Photocatalyst.

The production of hydrogen using a new type of heterogeneous photocatalyst under visible light is considered a remarkable essential pathway for sustainable, pure energy not only on the laboratory scale but also on a bigger scale. Hence, a new nanocomposite of mesoporous MnCoO, g-CN, and MnCoO@g-CN was produced utilizing a sol-gel method with variable MnCoO contents. The crystal structure of MnCoO was effectively confirmed by the X-ray diffraction pattern and integrated onto the g-CN structure. The MnCoO nanoparticles were displayed as spherical particles by TEM images and dispersed in a uniform way inside the g-CN nanosheet. The synthesized nanocomposites in the form of MnCoO@g-CN were examined as a new effective photocatalyst against glycerol as a source for H production with visible light. The MnCoO contents indicated a corroborative impact for the photocatalytic action related to the H production process. A maximum H production molecular value was observed (21,870 μmol·g·h) for a 1.5 wt % MnCoO@g-CN nanocomposite as a considerable increase in its photocatalytic activity. The yields of H are ∼55 and 23 times higher than those of g-CN and MnCoO, respectively. Up to five times cycles of visible lighting were the maximum number of repeated cycles by which the 1.5 wt % MnCoO@g-CN product showed higher stability and durability.