三维g-C_(3)N_(4)泡沫负载Cu(OH)2纳米片的制备及其光催化还原CO_(2)性能

Preparation of 3D g-C_(3)N_(4)foam supported Cu(OH)2 nanosheets for photocatalytic CO_(2)reduction

为了改善g-C_(3)N_(4)光催化还原CO_(2)过程中的气体传质、吸附和光生电荷分离效率,分别从泡沫孔结构构筑和构建异质结两方面进行光催化材料设计。采用表面活性剂发泡法制备g-C_(3)N_(4)泡沫(g-C_(3)N_(4)Foam),以此为基体通过化学镀铜和氢氧化处理制备g-C_(3)N_(4)泡沫负载Cu(OH)2纳米片(Cu(OH)_(2)/CNF)复合材料,对其结构和光催化性能进行分析。结果表明:g-C_(3)N_(4)Foam和Cu(OH)_(2)/CNF均展现出发达的三维微米孔网络结构,这种结构可从动力学层面优化CO_(2)在气-固催化反应中的传质和吸附,使CO_(2)吸附容量分别达到3.97 cm^(3)/g和3.59 cm^(3)/g,为g-C_(3)N_(4)粉末的2.96倍和2.68倍;同时,Cu(OH)_(2)/CNF样品中还形成大量二维Cu(OH)_(2)纳米片结构,不仅可以拓宽复合材料的光利用范围,还可通过g-C_(3)N_(4)/Cu(OH)_(2)异质结的构建促进光生电子向Cu(OH)_(2)表面转移,提升光生电荷分离效率;制备的Cu(OH)_(2)/CNF复合样品CO产率达到11.041μmol·g^(-1)·h^(-1),为g-C_(3)N_(4)Foam和g-C_(3)N_(4)粉末样品的2.76倍和6.83倍。

To optimize the gas transfer,adsorption and photo-generated charge separation in the process of photocatalytic CO_(2)reduction by g-C_(3)N_(4),the photocatalytic materials were designed from the aspects of foam pore structure and heterojunction construction.The typical g-C_(3)N_(4)foam was first constructed using surfactant foaming method,and then Cu(OH)_(2)nanosheets were loaded to prepare the Cu(OH)_(2)/CNF composites with projects of electroless copper plating and hydrogen oxidation treatment.The structure and photocatalytic properties of the as-prepared samples were investigated.The results show that g-C_(3)N_(4)foam and Cu(OH)_(2)/CNF all demonstrate developed structures with 3D micron pore frameworks,which is conducive to improving CO_(2)diffusion and adsorption at dynamics during gas-solid catalytic process.The adsorption amounts of CO_(2)for g-C_(3)N_(4)foam and Cu(OH)_(2)/CNF are respectively 3.97 cm^(3)/g and 3.59 cm^(3)/g,which are 2.96 times and 2.68 times respectively higher than that of pure g-C_(3)N_(4)powder.Moreover,many Cu(OH)_(2)nanosheets are also formed in the Cu(OH)_(2)/CNF samples which provide a way to simultaneously broaden light absorption and form heterojunction between g-C_(3)N_(4)and Cu(OH)_(2).This heterojunction can accelerate the separation of photo-generated e^(-)-h^(+)and make photo-generated electrons transfer from g-C_(3)N_(4)to Cu(OH)_(2).As a result,the Cu(OH)_(2)/CNF has demonstrated optimal photocatalytic activity with CO production rate at 11.041μmol·g-1·h-1,which is 2.76 times and 6.83 times respectively higher than that of g-C_(3)N_(4)foam and g-C_(3)N_(4)powder.