Kishore M R Ashwin, Varunaa R, Bayani Amirhossein, Larsson Karin
Department of Chemistry, Ångström Laboratory, Uppsala University, Box 538, 751 21 Uppsala, Sweden.
Department of Physics, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu 610101 India.
Sci Rep. 2020 Dec 8;10(1):21411. doi: 10.1038/s41598-020-77999-8.
The search for an active, stable, and abundant semiconductor-based bifunctional catalysts for solar hydrogen production will make a substantial impact on the sustainable development of the society that does not rely on fossil reserves. The photocatalytic water splitting mechanism on a [Formula: see text] monolayer has here been investigated by using state-of-the-art density functional theory calculations. For all possible reaction intermediates, the calculated changes in Gibbs free energy showed that the oxygen evolution reaction will occur at, and above, the potential of 2.06 V (against the NHE) as all elementary steps are exergonic. In the case of the hydrogen evolution reaction, a potential of 0.52 V, or above, was required to make the reaction take place spontaneously. Interestingly, the calculated valence band edge and conduction band edge positions for a [Formula: see text] monolayer are located at the potential of 2.60 V and 0.56 V, respectively. This indicates that the photo-generated holes in the valence band can oxidize water to oxygen, and the photo-generated electrons in the conduction band can spontaneously reduce water to hydrogen. Hence, the results from the present theoretical investigation show that the [Formula: see text] monolayer is an efficient bifunctional water-splitting catalyst, without the need for any co-catalyst.
寻找一种用于太阳能制氢的活性高、稳定性好且储量丰富的半导体基双功能催化剂，将对不依赖化石燃料储备的社会可持续发展产生重大影响。本文利用最先进的密度泛函理论计算研究了[化学式：见原文]单层上的光催化水分解机理。对于所有可能的反应中间体，计算得到的吉布斯自由能变化表明，由于所有基元步骤都是放能的，析氧反应将在2.06 V（相对于标准氢电极）及以上的电位发生。在析氢反应的情况下，需要0.52 V或更高的电位才能使反应自发进行。有趣的是，计算得到的[化学式：见原文]单层的价带边缘和导带边缘位置分别位于2.60 V和0.56 V的电位。这表明价带中的光生空穴可以将水氧化为氧气，导带中的光生电子可以自发地将水还原为氢气。因此，本理论研究结果表明，[化学式：见原文]单层是一种高效的双功能水分解催化剂，无需任何助催化剂。
