Green synthesis of carbon nitride by NaNO3/NaCl eutectic molten salt and study on its versatile photocatalytic performance

Abstract

The green synthesis of carbon nitride by NaNO3/NaCl eutectic molten salt was successfully realized in this study. Based on this envisaging, the heat treatment temperature has been successfully lowered to 340 °C to modulate and optimize the carbon nitride structure. The prepared target photocatalysts were characterized by using various characterization methods (SEM, BET, XRD, XPS, UV–Vis DRS, FT-IR, PL and transient photocurrents), which confirmed the practicability of the proposed strategy. The incorporation of doped Na+ ions and introduced cyano groups into the main structure can enhance the separation and migration capability of photo-induced electrons and holes, thereby inhibiting their recombination. Consequently, the much-enhanced photocatalytic activity of the obtained target catalyst was achieved and demonstrated through comprehensive tests such as photocatalytic degradation of organic dyes, photocatalytic degradation of organic pesticides, photocatalytic degradation of organic flotation reagent, and photocatalytic hydrogen evolution. Among them, g-CN-A-T-NaNO3/NaCl exhibited the highest photocatalytic activity and the highest repeated usage stability compared with the original sample. Additionally, the active species yielded in the system and possible mechanism for photocatalytic degradation of organic substances and photocatalytic H2 production was achieved based on systematically trapping experiments and electron spin resonance analysis.