g-C_3N_4/双钙钛矿复合材料的制备及氧催化性能

Preparation and Oxygen Catalytic Performance of g-C_3N_4/Double Perovskite Composites

通过溶胶-凝胶法制备出不同Ni掺杂比例的双钙钛矿Sr_2Ni_xCo_(2-x)O_6(x=0.2,0.4,0.6,0.8),通过热分解法制备出具有层状结构的纳米颗粒g-C_3N_4,并制备其复合物催化剂。将双钙钛矿和g-C_3N_4分别制备成双功能电极片,用于测试其对氧还原(ORR)和氧析出(OER)的催化活性,然后选取具有最佳氧催化活性的Ni掺杂比例x=0.4的双钙钛矿与一定重量比例的g-C_3N_4进行复合,测试复合催化剂的氧催化活性。结果表明,复合后的催化剂催化效果明显优于单一催化剂,当g-C_3N_4添加量占双钙钛矿的30%(w/w)时复合催化剂催化氧还原反应的最大电流密度为395.7 mA·cm^(-2)(-0.6 V vs Hg/HgO),氧析出反应的最大电流密度为372.0mA·cm^(-2)(1 V vs Hg/HgO),这表明g-C_3N_4与Sr_2Ni_(0.4)Co_(1.6)O_6复合后协同催化能够提高双钙钛矿的氧催化活性。

Double perovskite Sr2NixCo2-xO6 (x=0.2, 0.4, 0.6, 0.8) with different Ni doping ratios were prepared by sol-gel method,and nanoparticles g-C3N4 with layered structure was prepared by thermal decomposition. Synthesis of double perovskite and g-C3N4 composite that were used as bifunctional catalysts, which were prepared into bifunctional electrodes, and used to test its catalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Then, the doping ratio (x=0.4) of Ni in double perovskite with the best oxygen catalytic activity was selected to be composited with a certain weight ratio of g-C3N4, testing the catalytic activity of the composite catalysts. The results show that the composite catalysts were obviously better than the single catalysts. When the amount of g-C3N4 added was 30% of the mass of the double perovskite, the maximum current densities of the catalytic ORR was 395.7 mA·cm^-2 (-0.6 V vs Hg/HgO), the catalytic OER was 372.0 mA·cm^-2 (1 V vs Hg/ HgO). This indicates that the synergistic catalysis of g-C3N4 and Sr2Ni0.4Co1.6O6 could improve the catalytic activity of the double perovskite.