Carbon layer derived carrier transport in Co/g-C3N4 nanosheet junctions for efficient H2O2 production and NO removal.

• Co nanoparticles are embedded in N-doped carbon nanotubes (Co-N-carbon nanotubes). • A further thermal condensation between Co-N-carbon nanotubes and g-C 3 N 4 nanosheets occurred to form Co/g-C 3 N 4 junctions. • The Co/g-C 3 N 4 junctions with Schottky barrier existed between the carbon layer coated Co nanoparticles and g-C 3 N 4 nanosheets. • The Schottky junction composites shows a photocatalytic H 2 O 2 generation efficiency of 3618 μmolL−1h−1 without co-catalysts. • NO removal rate of 62 % is higher than that of the commercial P25 (TiO 2). Co nanoparticles are embedded in N-doped carbon nanotubes (Co-N-carbon nanotubes) using combinations of mechano-chemical pre-treatment and thermal polymerization process (at 760 °C). A further thermal polymerization process done on these Co-N-carbon nanotubes and ultrathin graphitic carbon nitrate (g-C 3 N 4) leads to the formation of Co nanoparticles (coated with carbon layers) embedded g-C 3 N 4 nanosheets composite, along with the disappearance of carbon nanotube morphology on the material. The Co/g-C 3 N 4 junctions are constructed with a Schottky barrier formed between the carbon layer coated Co nanoparticles and the g-C 3 N 4 nanosheets. The presence of carbon layers in the composite system facilitates transport of photogenerated electrons at the Fermi level of Co, which results in enhanced photocatalytic H 2 O 2 generation and NO oxidation performances of the composite material in visible light irradiation condition with excellent cyclic stability. The Schottky junction composites constructed using optimized preparation conditions in case of no co-catalyst incorporation shows a photocatalytic H 2 O 2 generation efficiency of 3618 μmolL−1h−1 which is about 1000 times of that of pristine g-C 3 N 4 nanosheets. A NO removal rate of 62 % (higher than that of the commercial P25 (TiO 2)) is also observed. These results provide possible approaches on constructing advanced photocatalysts for energy and environmental applications. [ABSTRACT FROM AUTHOR]