Xue Ning, Lin Zheng, Li Pengkun, Diao Peng, Zhang Qianfan
School of Materials Science and Engineering, Beihang University, Beijing 100191, P. R. China.
ACS Appl Mater Interfaces. 2020 Jun 24;12(25):28288-28297. doi: 10.1021/acsami.0c07088. Epub 2020 Jun 15.
The electrochemical hydrogen evolution reaction (HER), as a promising route for hydrogen production, demands efficient and robust noble-metal-free catalysts. Doping foreign atoms into an efficient catalyst such as CoSe could further enhance its activity toward the HER. Herein, we developed a solvothermal ion exchange approach to doping S into CoSe nanosheets (NSs). We provide a combined experimental and theoretical investigation to establish the obtained S-doped CoSe (S-CoSe) nanoporous NSs as highly efficient and Earth-abundant catalysts for the HER. The optimal S-CoSe catalyst delivers a catalytic current density of 10 mA·cm for the HER at an overpotential of only 88 mV, demonstrating that S-CoSe is one of the most efficient CoSe- and CoS-based catalysts for the HER. We performed density functional theory (DFT) calculations to determine the stable structural configurations of S-CoSe, and on the basis of which, we calculated the hydrogen adsorption Gibbs free energy (Δ) on CoSe, CoS, and the S-CoSe and the barrier energies of the rate-determining step of the HER on S-CoSe. DFT calculations reveal that S-doping not only decreases the absolute value of Δ (move toward zero) but also significantly lowers the kinetic barrier energy of the rate-determining step of the HER on S-CoSe, leading to a greatly improved HER performance.
电化学析氢反应（HER）作为一种很有前景的制氢途径，需要高效且耐用的无贵金属催化剂。将外来原子掺杂到诸如CoSe这样的高效催化剂中，可以进一步提高其对HER的活性。在此，我们开发了一种溶剂热离子交换方法，将S掺杂到CoSe纳米片（NSs）中。我们提供了实验和理论相结合的研究，以确定所制备的S掺杂CoSe（S-CoSe）纳米多孔NSs是用于HER的高效且储量丰富的催化剂。最佳的S-CoSe催化剂在仅88 mV的过电位下，HER的催化电流密度为10 mA·cm，这表明S-CoSe是用于HER的最有效的基于CoSe和CoS的催化剂之一。我们进行了密度泛函理论（DFT）计算，以确定S-CoSe的稳定结构构型，并在此基础上，计算了CoSe、CoS、S-CoSe上的氢吸附吉布斯自由能（Δ）以及S-CoSe上HER速率决定步骤的势垒能。DFT计算表明，S掺杂不仅降低了Δ的绝对值（向零移动），而且显著降低了S-CoSe上HER速率决定步骤的动力学势垒能，从而大大提高了HER性能。
