Recycling Waste Melamine-Formaldehyde Resin as a Photocatalytic Enhancer for g-C<sub>3</sub>N<sub>4</sub> Photocatalysts and Application in Photoelectrochemical (PEC) Reactions
Kyung Suh Kim, Seung Yeon Choi, Tae Wu Kim, Myung Jong Kang
Abstract
Melamine-formaldehyde (MF) resin, one of the thermoset plastics, has been widely used due to its own characteristics such as hardness, thermal resistance, scratch resistance, and so on. However, due to those physical properties, it is hard to recycle after it is used. In this study, we developed a new experimental approach to recycle after-use MF resin as an enhancer for synthesizing g-C 3 N 4 photocatalysts. By adding the optimized amount of MF resin during the thermal synthesizing process of g-C 3 N 4 from urea, the melamine-formaldehyde resin added g-C 3 N 4 photocatalysts (MR photocatalysts) showed 2 times increased photocatalytic efficiency measured by the degradation reaction of methyl orange (MO) compared with the pristine g-C 3 N 4 photocatalyst. As fabricated photoelectrodes with the above photocatalysts, the optimized MR photocatalysts showed 141% enhanced photoelectrochemical properties with decreased electrochemical impedance values and onset potentials ( V onset ). The underlying photocatalytic/photoelectrochemical properties of the MR photocatalysts associated with the catalytic efficiency were investigated by employing various characterization methods including XPS, UV–visible, and TRPL measurements.