Density Functional Theory Study of a Graphdiyne-Supported Single Au Atom Catalyst for Highly Efficient Acetylene Hydrochlorination

In this work, supported single Au on graphdiyne is examined as an efficient catalyst for acetylene hydrochlorination. The adsorption of reactants C2H2 and HCl has a paramount influence on the reaction mechanism. It is indicated that C2H2 adsorption is much stronger than the counterpart of HCl for most of the investigated cases. An Eley–Rideal (E–R) mechanism is first investigated, which is initiated with C2H2 adsorption. In the following steps, the adsorbed C2H2 becomes the site to bind and activate HCl, which leads to formation of the product. It is also revealed that single Au experienced a redox cycle along the reaction pathway. The largest barrier is calculated to be 0.57 eV, corresponding to the product desorption. On the other hand, a novel Langmuir–Hinshelwood (L–H)-like mechanism is also reported, which started with coadsorption of HCl and C2H2. It is noted that the barriers of the LH mechanism are smaller than those of the ER mechanism. Moreover, supported single Au on graphdiyne has much improved performance than the counterpart on pristine graphene and single-walled carbon nanotube support. This work clearly demonstrated the superior performance of supported single Au in acetylene hydrochlorination and the potential of novel support graphdiyne in single-atom catalysis.