Density functional theory study on the decomposition mechanism of HFC-32 on a Cu(1 1 1) surface: The impact of H2O and O2

•The dissociation mechanism of HFC-32 on the Cu(111) surface are investigated.•Hydrogen bonds promote the adsorption of HFC-32 molecule on the Cu(111) surface.•O atom and H2O molecule on the Cu(111) surface can promote the dissociation of HFC-32.•The air in the organic Rankine cycle system should be emptied as much as possible.