Electronic and electrocatalytic properties of PbTiO: unveiling the effect of strain and oxygen vacancy.

First-principles calculations based on density-functional theory have been used to investigate the effect of biaxial strain and oxygen vacancy on the electronic, photocatalytic, and electrocatalytic properties of PbTiO oxide. Our results show that PbTiO has a high exciton binding energy and a band gap that can be easily moderated with different strain regimes. From a reactivity viewpoint, the highly exothermic adsorption of hydrogen atoms in both pristine and strained PbTiO structures does not make it a potential electrocatalyst for the hydrogen evolution reaction. Fortunately, the presence of oxygen vacancies on the PbTiO surface induces moderate adsorption energies, making the reduced PbTiO suitable for hydrogen evolution reaction processes.