Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , Suzhou 215123, China.
Nano Lett. 2015 Nov 11;15(11):7616-20. doi: 10.1021/acs.nanolett.5b03446. Epub 2015 Oct 22.
High-performance electrocatalysts with superior stability are critically important for their practical applications in hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Herein, we report a facile method to fabricate urchin-like CoP nanocrystals (NCs) as catalyst for both HER and ORR with desirable electrocatalytic activities and long-term stability. The urchin-like CoP NCs with a diameter of 5 μm were successfully prepared by a hydrothermal reaction following a phosphidation treatment in N2 atmosphere and present excellent HER catalytic performance with a low onset overpotential of 50 mV, a small Tafel slope of 46 mV/decade, and an exceptional low overpotential of ~180 mV at a current density of 100 mA cm(-2) with a mass loading density of 0.28 mg/cm(2). Meanwhile, a remarkable ORR catalytic activity was observed with a half-potential of 0.7 V and an onset potential of 0.8 V at 1600 rpm and a scan rate of 5 mV s(-1). More importantly, the urchin-like CoP NCs present superior stability and keep their catalytic activity for at least 10 000 CV cycles for HER in 0.5 M H2SO4 and over 30 000 s for ORR in 0.1 M KOH, which is ascribed to their robust three-dimensional structure. This urchin-like CoP NCs might be a promising replacement to the Pt-based electrocatalysts in water splitting and fuel cells.
具有优异稳定性的高性能电催化剂对于其在析氢反应（HER）和氧还原反应（ORR）中的实际应用至关重要。在此，我们报告了一种简便的方法来制备具有理想电催化活性和长期稳定性的仿刺参状 CoP 纳米晶体（NCs）作为催化剂用于 HER 和 ORR。直径为 5 μm 的仿刺参状 CoP NCs 通过在 N2 气氛下进行磷化处理的水热反应成功制备，具有出色的 HER 催化性能，起始过电位低至 50 mV，Tafel 斜率小至 46 mV/decade，在质量负载密度为 0.28 mg/cm(2)时，电流密度为 100 mA cm(-2)时的过电位低至~180 mV。同时，在 1600 rpm 和 5 mV s(-1)的条件下，观察到显著的 ORR 催化活性，半波电位为 0.7 V，起始电位为 0.8 V。更重要的是，仿刺参状 CoP NCs 表现出优异的稳定性，在 0.5 M H2SO4 中用于 HER 的至少 10 000 个 CV 循环和在 0.1 M KOH 中用于 ORR 的超过 30 000 s 的时间内保持其催化活性，这归因于其坚固的三维结构。这种仿刺参状 CoP NCs 可能是水分解和燃料电池中替代基于 Pt 的电催化剂的有前途的选择。
