What is claimed is:
1. A preparation method of a carbon nitride electrode material, characterized by comprising the following steps:
(1) Preparing a precursor film: vertically immersing a clean conductive substrate A into a saturated CN precursor aqueous solution, then immediately taking out the conductive substrate A, forming a uniform precursor film layer on the conductive substrate A; after the surface has been dried, adjusting the thickness of the precursor film layer by repeating the above steps of dipping and drying cycles for many times to form multiple layers, and air-drying or drying the obtained precursor film in a 60° C. drying oven for later use;
(2) Preparing the CN electrode: putting the dry precursor film obtained in step (1) into a glass tube, introducing nitrogen gas to discharge air in the glass tube, binding the glass tube opening with tin foil paper, then putting the glass tube into a furnace with N 2 atmosphere to calcinate at a temperature, and cooling to obtain the uniform CN film electrode.
2. The preparation method of the carbon nitride electrode material according to claim 1 , wherein the temperature of the saturated solution in the step (1) is determined by the actual solubility of the precursor in water, the temperature is 60-120° C., and different precursors may be extended to a wider range of temperature.
3. The preparation method of the carbon nitride electrode material according to claim 1 , wherein the precursor is thiourea, urea, ammonium thiocyanate or guanidine carbonate, with the solubility in water at 70° C. of about 0.9 g·mL −1 , 2.4 g·mL −1 , 4.6 g·mL −1 , and 0.7 g·mL −1 , respectively.
4. The preparation method of the carbon nitride electrode material according to claim 1 , wherein the conductive substrate A in the step (1) includes fluorine-doped SnO 2 conductive glass (FTO), indium tin oxide conductive glass (ITO), carbon paper, or an FTO electrode coated with a TiO 2 film.
5. The preparation method of the carbon nitride electrode material according to claim 1 , wherein in the step (2), the reaction temperature of the furnace with N 2 atmosphere is 450-600° C., the high-temperature calcination lasts for 2-4 h, and the heating rate is 2-40° C.·min −1 .