Based On The Preparation Of Graphite Phase Carbon Nitride Nanomaterials And Their Photocatalytic Properties

With the rapid development of the world's industry and economy,the energy crisis and environmental pollution are becoming more and more serious.In recent years,photocatalysis technology has become one of the global research hotspots because of its advantages of solar energy utilization and environmental protection.The development of high efficiency catalysts is a key problem in the development of photocatalytic/electrocatalytic technology.g-C₃N₄ has the appropriate band gap(2.7e V),certain visible light response capability,good chemical and thermal stability,special easily regulated electronic structure and cheap and easy to obtain,etc.However,the traditional g-C₃N₄ has such defects as small specific surface area,slow transfer and separation of photogenic carriers,and poor oxidation capacity.In this paper,a series of functionalized materials and composites based on graphite carbon nitride(g-C₃N₄)were synthesized by means of protonation of s upramolecular precursors and semiconductor coupling,and the y were used to photocatalytic pollutant degradation and photoelectric oxygen evolution reaction(OER).The work completed is as follows:(1)SH-g-C₃N₄ nanometer material was obtained by introducin g nitric acid to treat supramolecular precursor,with ultra-thin porous 2D structure.It was found that protonation did not change the crystal structure of g-C₃N₄ material.Under visible light irradiation,the photocatalytic degradation of rhodamine B and bisphenol A by SH-g-C₃N₄ was significantly improved.In addition,SH-g-C₃N₄ exhibited a lower initiation potential,overpotential,and tafel slope in the dark.In addition,it showing a smaller tafel slope in visible light than commercial Ru O ₂ and Ir O₂.Based on the solid energy band theory,the reaction mechanism of improving photocatalysis and photocatalysis of g-C₃N₄ porous nano-sheet was studied.This work provides an idea for the synthesis of a large number of efficient g-C₃N₄ catalysts.(2)Amorphous g-C₃N₄/black TiO₂ composite nanomaterials were synthesized by simple solvent thermal method combined with thermal condensation.Compared with pure g-C₃N₄ and TiO₂,composite materials have a more negative conducting band position,a faster photogenerated charge mobility and a lower recombination rate.Under visible light irradiation,the composite g-C₃N₄/black TiO₂ microspheres showed stronger photocatalytic degradation capacity of rhodamine B,which was 17.4 times and 15.7 times higher than that of g-C₃N₄ and black TiO₂ respectively.It also exhibited superior electrochemical OER activity,and showing a smaller initial potential,overpotential,and lower tafel slope in both dark and light conditions.This work provides a simple method for the effective modi fication of g-C₃N₄.