Adsorption of hydrogen sulphide on Metal-Organic Frameworks

Three new sets of interatomic potentials to model hydrogen sulphide (H ₂S) have been fitted. One of them is a 3-sites potential (which we named 3S) and the other two are 5-sites potentials (which we named 5S and 5Sd). The molecular dipole of the 3S and 5S potentials is 1.43 D, which is the value usually employed for H₂S potentials, while the dipole of the 5Sd is the dipole measured experimentally for the H₂S molecule, circa 0.974 D. The interatomic potentials parameters were obtained by fitting the experimental vapour-liquid equilibrium, vapour pressure and liquid density curves. The potential parameters fitted so far for H₂S have been obtained applying long-range corrections to the Lennard-Jones energy. For that reason, when a cut and shift of the Lennard-Jones potentials is applied they do not yield the correct results. We employed a cut and shift of the Lennard-Jones potentials in the fitting procedure, which facilitates the use of the new potentials to model H₂S adsorption on systems such as Metal-Organics Frameworks (MOFs). We have employed the newly developed potentials to study the adsorption of H₂S on Cu-BTC, MIL-47 and IRMOF-1 and the results agree with the available electronic structures calculations. All calculations (both quantum and interatomic potential-based) predict that H₂S does not bind to the Cu atoms in Cu-BTC.