Composite Foams of the Graphitic Carbon Nitride@Carbon Nanofibrils Conferred a Superamphiphilic Property and Reinforced Thermal Stability

Abstract

Herein, we demonstrated the preparation of novel three-dimensional (3D) superamphiphilic g-C 3 N 4 @carbon nanofibers foam (g-C 3 N 4 @CNFs) via a two-step approach: liquid nitrogen treatment-freeze-drying; the foams possessed good thermal stability. In this approach, melamine acted as a nitrogen source, and nanofibrillated cellulose (NFCs) functioned as a 3D skeleton. The thermal stability of the as-prepared g-C 3 N 4 @CNFs-3 foam was much higher than that of g-C 3 N 4 @CNFs-1, as indicated by thermogravimetric data, including an increase of the onset weight loss point (T onset ) by 238.6 °C and an improvement of the maximal weight loss rate (T max ) by 258.8 °C. The combination of g-C 3 N 4 with CNFs conferred a reduction in the heat release rate (ca. −86%) and the total heat release (ca. −75%). Furthermore, the composition of the hydrophilically oxygenated functional groups and hydrophobic triazine domains in g-C 3 N 4 @CNFs rendered it a unique amphiphilic property (contact angle close to 0°w ithin 1.0 s for water and 0°within 12 ms for hexane). A high storage capacity for water and various organic solvents of the superamphiphilic g-C 3 N 4 @CNFs foam was found, up to 40−50 times its original weight. The discovery of these superamphiphilic foams is of great significance for the development of superwetting materials and may find their applications in oil emulsion purification and catalyst support fields.

Cayanamide Group Functionalized Crystalline Carbon Nitride Aerogel for Efficient CO2 Photoreduction

“…Knowing the calculated bandgap values (Figure 2b) and the measured CB minimum (Figure S13, Supporting Information), the corre-sponding band structures of all the samples could then be reasonably schemed (Figure 2c). Given the further exfoliation induced by the freeze-drying process, [33,34] it is reasonable that CCN aerogels obtained via hydrogelation with different amounts of CCN powder would possess different crystal and morphological structures (e.g., S BET , thickness and interplanar stacking distances), contributing to their different band structures. Notably, all the CCN aerogels exhibit CB positions more negatively than PCN and CCN, which endows the photogenerated electrons with a stronger driving force for photocatalytic CO 2 reduction.…”