School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China.
Department of Materials Science and Engineering, Tufts University, Medford, MA, 02155, USA.
Small. 2023 Jun;19(22):e2300200. doi: 10.1002/smll.202300200. Epub 2023 Mar 3.
Currently, the rarity and high cost of platinum (Pt)-based electrocatalysts seriously limit their commercial application in fuel cells cathode. Decorating Pt with atomically dispersed metal-nitrogen sites possibly offers an effective pathway to synergy tailor their catalytic activity and stability. Here active and stable oxygen reduction reaction (ORR) electrocatalysts (Pt Ni@Ni-N -C) by in situ loading Pt Ni nanocages with Pt skin on single-atom nickel-nitrogen (Ni-N ) embedded carbon supports are designed and constructed. The Pt Ni@Ni-N -C exhibits excellent mass activity (MA) of 1.92 A mg and specific activity of 2.65 mA cm , together with superior durability of 10 mV decay in half-wave potential and only 2.1% loss in MA after 30 000 cycles. Theoretical calculations demonstrate that Ni-N sites significant redistribute of electrons and make them transfer from both the adjacent carbon and Pt atoms to the Ni-N . The resultant electron accumulation region successfully anchored Pt Ni, that not only improves structural stability of the Pt Ni, but importantly makes the surface Pt more positive to weaken the adsorption of *OH to enhance ORR activity. This strategy lays the groundwork for the development of super effective and durable Pt-based ORR catalysts.
目前，铂 (Pt) 基电催化剂的稀有性和高成本严重限制了其在燃料电池阴极中的商业应用。在原子分散的金属-氮位点上修饰 Pt 可能提供了一种有效的途径来协同调整其催化活性和稳定性。在此，通过在单原子镍-氮 (Ni-N) 嵌入碳载体上原位负载具有 Pt 皮的 Pt Ni 纳米笼，设计并构建了活性和稳定的氧还原反应 (ORR) 电催化剂 (Pt Ni@Ni-N -C)。Pt Ni@Ni-N -C 表现出优异的质量活性 (MA) 为 1.92 A mg -1 和比活性为 2.65 mA cm -2 ，以及出色的耐久性，在半波电位中仅衰减 10 mV，在 30000 次循环后 MA 仅损失 2.1%。理论计算表明，Ni-N 位点显著重新分配电子，使它们从相邻的碳和 Pt 原子转移到 Ni-N 。所得的电子积累区域成功地固定了 Pt Ni ，这不仅提高了 Pt Ni 的结构稳定性，而且重要的是使表面 Pt 更正，从而削弱*OH 的吸附，从而增强 ORR 活性。该策略为开发超有效和耐用的 Pt 基 ORR 催化剂奠定了基础。
