Enhanced Photoelectrochemical Cathodic Protection Performance of the Secondary Reduced Graphene Oxide Modified Graphitic Carbon Nitride

Abstract

Graphitic carbon nitride (g-C3N4) is a promising material in the area of photoelectrochemical (PEC) cathodic protection. However, the fast secondary recombination of photogenerated charge carriers and the amphoteric property of g-C3N4 restrict its further application. In this work, the secondary reduced graphene oxide modified g-C3N4 (R-rGO-C3N4) was prepared by a thermal polycondensation method and subsequently secondary reduction process. The presence of reduced graphene oxide (rGO) and the increased reduction degree of rGO were proved by the X-ray photoelectron spectroscopy and UV/Vis diffuse reflectance spectroscopy. The rGO modification enhanced the electrical conductivity of g-C3N4, promoting the transfer and separation of the photogenerated charge carriers. It adjusted the band structure of g-C3N4 toward more negative direction, making it show stronger “n-type” semiconductor property. The properties were further improved after the secondary reduction of the rGO. These help to increase the PEC properties of g-C3N4, which makes a step toward the practical application of g-C3N4.