Determining The Catalytic Activity Of Oxygen Evolution Reaction On Metal Oxides Based On The Intrinsic Descriptors

The rapid development of human society has exacerbated the consumption of fossil energy,which courses serious damage to the natural environment and resources.Therefore,the pursuit of alternative energy has become a hot spot in the field of energy and catalysis.Oxygen evolution reaction（OER）,the anodic reaction of the majority electrochemical process,plays a vital role in energy conversion and storage.However,as a complex four-electron transfer reaction,OER suffers slow kinetics and requires high overpotential,which limits the efficiency of the overall reaction.Among the various OER catalysts,metal oxides have the advantages of high activity,low cost,and easy preparation,thus possessing the most promising application prospects.Currently,the development of OER metal oxides mainly relies on experimental trial and error and first-principle calculations,which greatly raises the time and economic cost.Herein,from the perspective of the adsorbate evolution mechanism（AEM）and the lattice oxygen mechanism（LOM）of OER,we used the electronic descriptorψto study the trend of adsorption energies of O-intermediates and oxygen vacancy formation energy of different metal oxide surfaces.Furthermore,we used the electronic descriptorψto describe and predict the OER activity of metal oxides,which provides useful guidance for the design of efficient OER catalysts.The research content includes the following two parts:Firstly,we studied the adsorption characteristics of O,OH,and OOH on salt-rock structure metal monoxide（MO）（100）surface,rutile structure dioxide（MO₂）（110）surface,and perovskite oxide（ABO₃）（100）surface.We recognized that the electronic descriptorψexhibits good linear relationships with the adsorption energy of O-intermediates,proving the availability of the adsorption descriptorψfor metal oxides.Besides,the descriptorψalso linearly scales with the p-band properties of surface oxygen of metal oxides（ε_p andε_p?）,which reveals the physical picture of the adsorption property of metal oxides.More importantly,we found the adsorption-energy difference between OH and OOH(（35）G_OH-（35）G_OOH)is material-dependent,thus the corresponding thermodynamic limitation can be broken on the surfaces of late-transition metal oxides.Based on the above investigation,we established the volcano model between the descriptorψand the OER overpotentialηof various metal oxide surfaces.The theoretical model is descriptive of the OER activity of metal oxides obtained from density functional theory（DFT）calculations and experiments.Compared with DFT calculations,the descriptorψis easily accessible,providing a new strategy for the design of efficient OER catalysts.Secondly,we identified the negative linear relationships between the descriptorψand the oxygen vacancy formation energy of perovskite oxides（ABO₃）.Our results show that the slopes of the above linear models are determined by the coordination of lattice oxygen atoms,as well as the radius and the f-electrons of the B cation,while the intercepts are closely related to the radius of the A cation.Therefore,we established the volcanic model between the descriptorψand the overpotentialsηof La-and Sr-based 3d perovskite oxides,for both the AEM and LOM.By comparing the volcano models of the AEM and LOM,we found that the corresponding peaks of volcanos have similar values ofψ.Moreover,LOM is more likely to occur on surfaces with a large value ofψ,due to the lower oxygen vacancy formation energy.Therefore,the descriptorψis descriptive and predictive for the catalytic activity of perovskite oxides under LOM,providing theoretical guidance for designing OER catalysts.In summary,we used the descriptorψto unveil the physical picture of surface adsorption and oxygen vacancy formation on metal oxides,established the linear models for adsorption energy and oxygen vacancy formation energy,the further constructed the catalytic volcano models of metal oxides for both AEM and LOM of OER,which helps the development of novel OER metal oxide catalysts.