Recent advance and perspectives in g-C3N4 based gas sensing materials: a review

Due to tunable electronic and morphology structure, stable physicochemical properties and simple preparation, graphitic carbon nitride (g-C3N4) has emerged as an attractive candidate in the field of gas sensing. However, the gas sensing performance of pristine g-C3N4 is not satisfactory, due to the large band gap, high recombination of electrons and holes and low carrier mobility, leading to poor conductivity and surface activity. Therefore, multiple methods have been conducted to tune its gas sensing performance by providing more surface adsorption sites and improving surface activity. This review systematically represents the structure, synthesis methods and properties of g-C3N4, and summarizes their applications in gas sensors. Specifically, the modification, charac-terization, enhanced gas sensing performance and sensing mechanism are discussed in detail. In the future, related work should focus on the aspects of designing hierarchical and open structures, doping heteroatoms and building heterostructure. Moreover, pi electron density control through carbon atoms injection or nitride atom vacancy and surface functional groups decorations are also proposed as potential strategies. This review is meaningful to promote the application of g-C3N4 in the field of gas sensing and development of novel strategy to enhance sensing performance.