Single-atom catalysts (SACS) not only have uniform metal active sites, but also have the potential for selective control. However, their application in high-temperature propane dehydrogenation remains challenging.
Based on this,Prof. Wang Xiaodong, Prof. Wang Aiqin and Prof. Lin Jian from Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Prof. Lin Sen from Fuzhou University (co-corresponding author) and othersA nitrogen-doped carbon (NC)-supported RU single atom with high stability and high efficiency propane (C3H8) dehydrogenation catalyst (RU1 NC) was reported. The turnover frequency of RU1 NC is at least 3 times higher than that of nanoparticles, and the propylene selectivity is about 92% at 560, with a low inactivation rate.
Using density functional theory (DFT) calculations, the authors considered the contribution of coordinated n species to the stability of RU1. With the increase of the number of N coordination, the formation energy of the RU1 center decreases significantly, and the Run3C and Run4 models are more thermodynamically stable. The results show that the coordination of N in the shell plays a crucial role in the stability of the RU1 center on the RU1 NC catalyst.
In addition, the authors evaluated the reactivity of Run3C-13 and Run4-14 with a Ru1 site for PDH reactions, where DFT calculations yielded a free energy barrier of 1 for the first dehydrogenation step (CH3CH2CH3* CH3CHCH3* +H*) for RUN3C-13 and Run4-14, respectively061 ev and 1357 ev。
In the transition state, the length of the c( )h bond broken by the two systems is 1., respectively483 and 1599 , the distance at which the c( )ru bond is formed is 2339 and 2352 å。For the second dehydrogenation step (ch3chch3* +h* ch3chch2* +2h*), the calculated free energy barrier is much lower (0. for run3c-13).701 EV, run4-14 is 0444 EV), indicating that the first dehydrogenation step is the determinant of the propane conversion rate.
peripheral-nitrogen effects on the ru1 centre for highly efficient propane dehydrogenation. nat. catal.,, doi: 10.1038/s41929-022-00885-1.