Graphene-Templated Cobalt Nanoparticle Embedded Nitrogen-Doped Carbon Nanotubes for Efficient Visible-Light Photocatalysis

Visible-light-assisted photocatalysis for the degradation of organic pollutants has recently become an efficient green approach in the field of environmental pollution abatement. Herein, graphene-templated zeolite-imidazolate framework (ZIF-67) derived, Co nanoparticle embedded, nitrogen-doped carbon nanotubes (G-Co-NCNTs) have been developed as a promising, inexpensive, high-yield photocatalyst to decompose reactive black 5 (RB5) under visible light irradiation. Morphology and structural characterization studies revealed that the growth of NCNTs along with pyridinic N content and the abundance of meso-micropores were greater in G-Co-NCNT than in Co-NCNT itself, suggesting the importance of graphene for in situ growth of ZIF-67 on GO. DRS study reveals that G-Co-NCNT exhibited low optical band gap (similar to 2.9 eV), assisting in the promotion of photoresponse behavior. The photocatalytic activity of our designed G-Co-NCNT hybrid showed excellent dye degradation ability (98%) after 60 min with a wide range of pH tolerance and promising reusability even after five cycles (93%) under visible light, while Co-NCNT demonstrated only about 62% dye degradation, further implying the importance of graphene and oriented NCNTs for dye degradation. Therefore, the G-Co-NCNT hybrid could be used as an efficient photocatalyst for the remediation of organic pollutants in wastewater.