Effect of Ni ions on thermal condensation kinetics and morphology of g-C3N4 nanosheets and their photo- and electro-chemical activity evolution

The effect of Ni ions on the thermal condensation kinetics, morphology, microstructure and photoelectric properties of layered g-C3N4 were tested. Ni ions were first incorporated into melamine before thermal polymerization. The morphologies of g-C3N4 from nanosheets to irregular tubular structure was created because of the effect of Ni atoms. The photo- and electro-chemical performance depended strongly on the morphologies of g-C3N4. Irregular tubular sample NCN675 with multiple scattering effect of light exhibited fast degradation for Rh B under visible light with a maximum degradation rate constant of 0.046 min−1. Electrocatalysis test indicates that NCN680 as N-doped carbon nanotubes with excellent electrocatalytic hydrogen and oxygen evolution rate (HER and OER), in which Tafel slopes of HER and OER are 111 and 107 mV/dec respectively. In addition, charge discharge test of supercapacitor confirms that NCN680 is the most suitable electrode material for supercapacitors and have larger specific capacitance (SC = 203.95F/g) when its current density is 1A/g. This study provides an important supplement for structure and performance transformation of carbon nitride compounds catalyzed by Ni.