Tien Nhac Duong, Kim Bo Hyeon, Yun Woo Hyun, Yoon Hyon Hee
Department of Chemical and Bio Engineering, Gachon University, Seongnam, Gyeonggi-do 461-701, Republic of Korea.
J Nanosci Nanotechnol. 2021 Mar 1;21(3):1890-1896. doi: 10.1166/jnn.2021.18916.
Low-cost Ni-based catalysts have been widely used for urea oxidation in direct urea fuel cells. However, they suffer from issues such as high overpotential, poor stability, and low activity. Herein, we demonstrate the synthesis of a highly porous nanostructured Ni-Co@C catalyst for efficient electrooxidation of urea, via the calcination of Co-doped Ni-based metal-organic framework (Ni/Co-MOF). The porosity of the MOF-derived particles is considerably higher than the Ni/Co-MOF precursor. Furthermore, the Co doping at 30 mol% significantly increases the peak current density and reduces the overpotential of the electro-oxidation of urea. A urea/H₂O₂ fuel cell with NiCo@C as the anode exhibits maximum power density of 3.4 and 20.0 mW cm with 0.5 M urea in 5 M KOH as anolyte at 25 and 80 °C, respectively. Thus, this work suggests that the highly porous Ni-Co@C catalysts derived from MOF templates can be used for urea oxidation and as efficient anode materials for urea-based fuel cells.
低成本的镍基催化剂已广泛用于直接尿素燃料电池中的尿素氧化。然而，它们存在诸如高过电位、稳定性差和活性低等问题。在此，我们通过对钴掺杂的镍基金属有机框架（Ni/Co-MOF）进行煅烧，展示了一种用于尿素高效电氧化的高度多孔的纳米结构Ni-Co@C催化剂的合成。MOF衍生颗粒的孔隙率明显高于Ni/Co-MOF前驱体。此外，30 mol%的钴掺杂显著提高了峰值电流密度，并降低了尿素电氧化的过电位。以NiCo@C作为阳极的尿素/H₂O₂燃料电池，在25和80 °C下，分别以5 M KOH中的0.5 M尿素作为阳极电解液时，最大功率密度为3.4和20.0 mW cm。因此，这项工作表明，由MOF模板衍生的高度多孔的Ni-Co@C催化剂可用于尿素氧化，并作为基于尿素的燃料电池的高效阳极材料。
