4.8. Simulation details
The CASTEP code in Materials studio was used to simulate the electronic structure and Gibbs free energy path of the catalytic model. The generalized gradient approximation proposed by Perdew, Burke, and Ernzerhof (GGA-PBE) was identified as the exchange correlation potential. In addition, ultrasoft pseudopotentials are used in the simulation process. The cut-off energy and MonkhorstPack mesh k-point were controlled to be 500.00 eV and 1 × 1 × 1, respectively. Convergence tolerance was considered to be an important parameter in the geometric optimization process, which mainly includes the following aspects: energy factor (5 × 10−6 eV per atom), maximum displacement (5 × 10−4 Å) and maximum force (0.01 eV Å−1). The DFT dispersion correction (DFT-D) was used to further analyze the electronic information of the catalyst model, which also considered the van der Waals interaction to improve the reliability of the simulation results. The CoP (011) and CoOOH (010) plane were used to further analyze the adsorption-desorption process and reaction pathways in the HER and OER processes. CP2K/Quickstep code was used for AIMD calculation. The exchange-correlation potential and pseudopotentials were set the same as in Materials Studio. The cutoff energy and van der Waals interactions were also considered, which were selected as 400 eV and DFT dispersion correction (DFT-D3) respectively in this module. The acquisition method of The AIMD simulations was determined to be canonical (NVT) ensemble. Among them, the target temperature and time step were set to 298.15 K and 1.0 fs, respectively.