Zhang Haochen, Li Chunsong, Lu Qi, Cheng Mu-Jeng, Goddard William A
State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan.
J Am Chem Soc. 2021 Mar 17;143(10):3967-3974. doi: 10.1021/jacs.1c00377. Epub 2021 Mar 5.
Electrochemical conversion of light alkanes to high-value oxygenates provides an attractive avenue for eco-friendly utilization of these hydrocarbons. However, such conversion under ambient conditions remains exceptionally challenging due to the high energy barrier of C-H bond cleavage. Herein, we investigated theoretically the partial oxidation of propane on a series of single atom alloys by using active intermediates generated during water oxidation as the oxidant. We show that by controlling the potential and pH, stable surface oxygen atoms can be maintained under water oxidation conditions. The free energy barrier for C-H bond cleavage by the surface oxygen can be as small as 0.54 eV, which can be surmounted easily at room temperature. Our calculations identified three promising surfaces as effective propane oxidation catalysts. Our complementary experiments demonstrated the partial oxidation of propane to acetone on Ni-doped Au surfaces. We also investigated computationally the steps leading to acetone formation. These studies show that the concept of exploiting intermediates generated in water oxidation as oxidants provides a fruitful strategy for electrocatalyst design to efficiently convert hydrocarbons into value-added chemicals.
将轻质烷烃电化学转化为高价值含氧化合物为这些碳氢化合物的环保利用提供了一条有吸引力的途径。然而，由于C-H键裂解的高能垒，在环境条件下进行这种转化仍然极具挑战性。在此，我们通过使用水氧化过程中产生的活性中间体作为氧化剂，从理论上研究了丙烷在一系列单原子合金上的部分氧化。我们表明，通过控制电势和pH值，可以在水氧化条件下维持稳定的表面氧原子。表面氧裂解C-H键的自由能垒可低至0.54电子伏特，在室温下很容易克服。我们的计算确定了三个有前景的表面作为有效的丙烷氧化催化剂。我们的补充实验证明了在镍掺杂的金表面上丙烷可部分氧化为丙酮。我们还通过计算研究了生成丙酮的步骤。这些研究表明，利用水氧化过程中产生的中间体作为氧化剂这一概念为电催化剂设计提供了一个富有成效的策略，可有效地将碳氢化合物转化为高附加值化学品。
