Graphene Nickel Iron Hydroxy Oxide Co-modified Tungsten Triode Photo Electrode

Tungsten trioxide electrode and its preparation method, and its application in photo catalytic decomposition of water use semiconductor photo catalytic technology to convert solar energy into hydrogen energy through water decomposition, and store and use hydrogen in the form of chemical energy, is one of the most promising ways to solve the current energy crisis.

Some scholars improve the efficiency of charge transfer by reducing graphene nickel iron hydroxyl oxide to modify tungsten triode. It includes the following steps:

(1)Tungstic acid and polyvinyl alcohol are added into the hydrogen peroxide solution, stirred to form a uniform solution to obtain the seed layer solution; the seed layer solution is coated on the conductive glass by spin coating method, and then the coated conductive glass is heated to 450-550 ℃, kept warm for 1.5-3 hours, cooled to room temperature to obtain the substrate; wherein, the amount of tungstic acid in the hydrogen peroxide solution is 70-80g / L. The dosage of PVA is 20-40g / L;

(2)Add hydrogen peroxide solution, oxalic acid, urea and hydrochloric acid of tungstic acid into acetonitrile, stir them to form a uniform solution to obtain hydrothermal reaction solution; put the substrate obtained in step (1) into hydrothermal reaction solution, conduct hydrothermal reaction at 160-200 ℃ for 1-6 hours, cool it to room temperature, take it out, wash and dry it, keep it at 450-550 ℃ for 1.5-3 hours, cool it to room temperature, and get trioxidation. Among them, the molar ratio of tungstic acid, oxalic acid, urea, hydrochloric acid and acetonitrile is (6-9); (10-20); (15-25); (100-200); (1 × 104-1.5 × 104);

(3)The aqueous solution of graphene oxide was coated on the nano-sized tungsten triode obtained in step (2) by spin coating method, and graphene oxide modified tungsten triode was obtained; in the atmosphere of argon or nitrogen, the graphene oxide modified tungsten triode was heated to 450-550 ℃, kept for 1.5-3 hours, and then cooled to room temperature to obtain reduced graphene modified tungsten triode ;

(4)Using the reduced graphene modified tungsten triode as the working electrode, the platinum sheet as the counter electrode and the saturated calomel electrode as the reference electrode to form a three electrode system, using the aqueous solution containing ferric chloride, nickel chloride, 4.5-5.5mmol/l sodium fluoride, 0.08-0.12mol/l potassium chloride and 0.98-1.02mol/l hydrogen peroxide as the electrolyte, using the cyclic voltammetry from - 0.5 ± 0.05v to 0.5 ± 0 The potential range of. 05V vs. SCE is looped and swept, then the working electrode is taken out, washed and dried to obtain the tungsten trioxide optical electrode.

Tungsten trioxide was grown on the surface of conducting glass by hydrothermal method, and then reduced graphene and NiFe hydroxy oxide were attached to the surface of semiconductor materials to form a uniform cocatalysis layer. The reduced graphene and NiFe hydroxyoxide were used to co modify the tungsten triode optical electrode. Under the synergistic effect of reduced graphene and Ni doped hydroxy iron oxide, the conductivity and photogenerated load of the photoelectric electrode were improved. The transfer efficiency of the current promotes the oxygen precipitation reaction at the electrode interface, and ultimately improves the efficiency of photocatalytic decomposition of water. This method can also be used to modify other semiconductors for photocatalysis, photoelectrochemical sensors, electrocatalysis and other fields.

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