The Preparation Of Semi-coke Based Porous Graphene Materials And Performance Of Photocatalytic Properties

Semi-coke is a solid product which dry distillation at the low temperature,it widely used in ferrosilicon,calcium carbide production,chemical fertilizer,metallurgical fuel,etc.However,with the increasing efforts in ecological environmental protection,energy conservation and consumption reduction,the market demand of semi-coke gradually slows down,and it result in the over-capacity of semi-coke industry and the oversupply of market.At the same time,the semi-coke powder produced by the semi-coke production can not be effectively utilized due to its excessively fine particle size.That situation not only leads to a great waste of carbon resources,but also leads to serious environmental pollution.Therefore,it is one of the urgent problems to seek a new way to utilize semi-coke powder to realize high value-added resource transformation of semi-coke.With high fixed carbon content,developed hole structure,metal photosensitive particles and unique organic structure characteristics,Semi-coke is used to prepare porous graphene materials with specific photocatalytic performance which used physical and chemical method.Meanwhile,the possible applications of this material are discussed,which opened up a new way for the material application of semi-coke and provided a new catalyst for the photocatalytic conversion of CO2.This article mainly did the following tasks:(1)semi-coke based porous graphene materials with uniform lamellar structure,high specific surface area and conjugate structure were successfully prepared by chemical oxidation molecular tailoring and molecular crosslinking with semi-coke powder as raw material.The photocatalytic reduction of CO2 to methanol was investigated using semi-coke based porous graphene as photocatalyst.The results showed that the semi-coke based porous graphene materials showed certain photocatalytic activity.When it was used as a photocatalyst,the yield of methanol was up to 57.32 mol/g-cat under UV irradiation for 12 h,about close to TiO2.(2)TiO2/semi-coke porous graphene materials were successfully prepared by hydrothermal method using semi-coke graphene materials as the carrier,and their photocatalytic reduction of CO2 to methanol was investigated.The results showed that the yield of methanol could be up to 74.37 mol/g cat when we use nano TiO2/SCPG composite as the photocatalyst under UV irradiation for 12 h.The photocatalyst of it has been improved greatly compared with the single photocatalyst.(3)C3N4/TiO2/semi-coke based porous graphene materials were prepared by chemical bath deposition and calcination which using nano TiO2/SCPG composite as the carrier,and their photocatalytic reduction of CO2 to methanol was investigated.The results showed that the yield of methanol could be up to 142.86 mol/g cat when we use ternary composite materials as the photocatalyst under UV irradiation for 12 h.It is ahout 2.2 times higher than that of pure TiO2.