煤基氧化石墨烯/钒酸铋复合物的构建及光还原CO_(2)应用

Coal-based graphene oxide/bismuth vanadate composite for photoreduction of CO_(2)

双碳目标下,煤炭资源的高附加值利用和CO_(2)资源化转化成为重要的研究课题,以煤为原料开发功能性煤基材料用于CO_(2)绿色转化展现出广泛的应用前景。以晋城无烟煤为碳质前体,采用高温石墨化耦合化学氧化策略制备得到煤基氧化石墨烯(CGO),进而通过蒸发诱导自组装手段在CGO上生长钒酸铋纳米片(BVO),成功构筑得到CGO/BVO纳米复合材料,其独特的二维/二维纳米片结构有助于复合材料在可见光照射下完成光催化还原CO_(2)过程。通过利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、紫外可见光漫反射光谱(UV-vis)以及光电化学测试等手段对复合样品的结构形貌和光电性质进行了测定。研究表明:BVO纳米片具有窄的带隙以及宽的可见光吸收范围,可以赋予CGO/BVO复合材料良好的光吸收能力。同时借助CGO自身优异的物理化学性质充当助催化剂,可以有效转移BVO纳米片被光激发后产生的载流子。通过2者充分接触产生的协同作用,减小了复合材料界面传输电阻,提高了光生电子的分离与转移速率和光催化剂表面电荷密度,从而促进了CO_(2)光还原制甲醇反应的进行。当复合材料中CGO与BVO质量比达到10∶1时,所制备的CGO/BVO样品将CO_(2)转化为甲醇的产率可达134.57μmol/(g·h),是纯BVO纳米片的1.7倍。这项研究为煤基高附加值新材料用于光催化转化CO_(2)制备甲醇提供了新思路。

Under the target of carbon neutrality and carbon peaking, the high value-added utilization of coal resources and CO_(2)resource conversion has become an important research topic, and the development of functional coal-based materials for CO_(2)green conversion using coal as raw material shows a wide range of application prospects. A high-temperature graphitization and chemical oxidation strategy was employed to prepare the coal-based graphene oxide(CGO)using the Jincheng anthracite as the carbonaceous precursor, and the composite CGO/BVO was constructed by growing BVO nanosheets on CGO through solvent evaporation, which could lead to an excellent photocatalytic CO_(2)reduction performance due to its unique 2D/2D nanosheet structure. The structural, morphology and optoelectronic properties of the composites were determined by X-ray diffractometer(XRD),transmission electron microscope(TEM),UV-vis diffuse reflectance spectroscopy(UV-vis)and photoelectrochemical tests. It was demonstrated that the BVO nanosheets with narrow band gap and wide visible light absorption range can confer a good light absorption ability to the CGO/BVO composites. Meanwhile, due to the good physicochemical properties of CGO as a co-catalyst, it can effectively transfer the carrier produced by BVO nanosheets after photoexcitation. The synergistic effect generated by the sufficient contact between the two reduces the interfacial transfer resistance of the composite material, increases the separation and transfer rate of photogenerated electrons and the surface charge density of the photocatalyst, and thus facilitates the CO_(2)photoreduction to methanol reaction. When the mass ratio of CGO to BVO in the composite reaches 10∶1,the methanol yield can reach 134.57 μmol/(g·h),which is 1.7 times higher than that of pure BVO nanosheets. This work provides an idea to the use of novel coal-based high value-added materials for the photocatalytic reduction of CO_(2)to methanol.