A comparative DFT study of HCHO decomposition on different terminations of the CoO(110) surface.

Density functional theory calculations have been performed to compare the HCHO decomposition on CoO(110)-A and (110)-B terminations. The results showed that the energy barriers of the two C-H bond cleavages of HCHO on the (110)-A termination were lower than those on the (110)-B termination, suggesting that the (110)-A termination had stronger HCHO decomposition ability than the (110)-B termination. Electronic structures revealed that the stronger HCHO decomposition ability of the (110)-A termination might be ascribed to the strong covalent bond between HCHO and the (110)-A termination, as well as the higher d-band center of Co ions on the (110)-A termination. Furthermore, we proposed that the preparation of CoO under oxygen-rich growth conditions was beneficial to HCHO decomposition because the (110)-A termination was more stable under oxygen-rich conditions.