Novel visible light driven crystalline carbon nitride-tungsten oxide composites for photodegradation of phenol

Abstract

A series of new tungsten oxide modified heptazine-based crystalline carbon nitride (CCN-(x)WO3) composite materials with different W loading amount (x = 0.1–1.0 wt%) were successfully synthesized via modified ionothermal and wet impregnation methods. The XRD and FTIR analyses results of confirmed the presence of highly ordered heptazine unit and C[tbnd]N terminal of CCN framework in the synthesized CCN-WO3 composites. The introduction of more WO3 has shifted the optical property of the CCN-WO3 composites to higher wavelength. The TEM and FESEM analyses on CCN-WO3 revealed the presence of WO3 in needle like shape decorated on the surface of CCN. Among, material CCN-(0.25)WO3 has exhibited the highest photocatalytic degradation of phenol which was 1.5 and 15 times higher than bare CCN and WO3 within 6 h exposure of visible light, respectively. The synergistic effect by co-existence of CCN and WO3 has induced the formation of highly ordered hepatize subunit of CCN, broadening light absorption in visible region, high surface area, low electron-hole recombination and high electron-transfer rate constant, which in turn enhanced the photocatalytic performance of CCN-WO3. The radical scavenger studies confirmed that the synthesized CCN-WO3 composite was an excellent visible light driven photocatalyst for phenol degradation.