Three-dimensional cubic ordered mesoporous carbon (CMK-8) as highly efficient stable Pd electro-catalyst support for formic acid oxidation

In this work, Pd nanoparticles were supported on two types of three-dimensional cubic highly orderedmesoporous carbon (CMK-8) by the sodium borohydride reduction method and the activity of the Pd/CMK-8 electro-catalysts towards formic acid oxidation was evaluated and compared with that ofcommercial Pd/C (E-TEK) catalyst. The catalysts were characterized by transmission electron microscopy(TEM), X-ray diffraction (XRD), cyclic voltammetry, and chronoamperometry. Cyclic voltammetryrevealed Pd/CMK-8 with larger pores as being the most electroactive with a mass specific activity(mA mgPd1) of 486.4 that exceeded not only that of the Pd/C (E-TEK) (386.5 mAmgPd1) but also that ofrecently reported Pd/CNT (200 mAmgPd1), Pd/Graphene (210mAmgPd1) and Pd/Vulcan XC 72 (193mAmgPd1).As demonstrated with chronoamperometry, the larger pore Pd/CMK-8 also proved to be the most stablecatalyst. This exceptional performance can be ascribed to the very high surface area and Ia3d symmetrythat yields a relatively isotropic graphitized structure with a high conductivity. In addition, the openframework of the 3-D bicontinous channels and highly ordered mesopores allows for an advanced masstransfer characteristics. The results show that CMK-8 support would significantly improve the poweroutput and stability of Pd-based electro-catalysts for formic acid oxidation本研究采用硼氢化钠还原法，将钯纳米颗粒负载于两种三维立方有序介孔碳（CMK-8）载体上，评估了Pd/CMK-8电催化剂对甲酸氧化的电催化活性，并与商用Pd/C（E-TEK）催化剂进行对比。研究采用透射电子显微镜（TEM）、X射线衍射（XRD）、循环伏安法以及计时电流法对所制备的催化剂进行了表征。循环伏安测试结果显示，具有更大孔径的Pd/CMK-8电催化剂表现出最优的电催化活性，其质量比活性（mA·mg⁻¹ Pd）可达486.4，不仅优于Pd/C（E-TEK）的386.5 mA·mg⁻¹ Pd，同时也优于近期报道的Pd/碳纳米管（CNT，200 mA·mg⁻¹ Pd）、Pd/石墨烯（210 mA·mg⁻¹ Pd）以及Pd/Vulcan XC 72（193 mA·mg⁻¹ Pd）。计时电流测试结果进一步证实，大孔径Pd/CMK-8同样展现出最优的催化稳定性。该优异性能可归因于其极高的比表面积与Ia3d对称结构，该结构可形成具备高导电性的相对各向同性石墨化骨架。此外，三维双连续通道与高度有序介孔构成的开放孔道结构，可实现优异的传质性能。研究结果表明，CMK-8载体可显著提升用于甲酸氧化的钯基电催化剂的功率输出与稳定性。