Tuning the electronic structure of the earth-abundant electrocatalysts for oxygen evolution reaction (OER) to achieve efficient alkaline water splitting – A review

Tuning the electronic structure of the electrocatalysts for oxygen evolution reaction (OER) is a promising way to achieve efficient alkaline water splitting for clean energy production (H2). At first, this paper introduces the significance of the tuning of electronic structure, where modifying the electronic structure of the electrocatalysts could generate active sites having optimal adsorption energy with OER intermediates, and that could diminish the energy barrier for OER, and that could improve the activity for OER. Later, this paper reviews the tuning of electronic structure along with catalytic performances, synthetic methodologies, chemical properties, and DFT calculations on various nanostructured earth-abundant electrocatalysts for OER in alkaline environment. Further, this review discusses the tuning of the electronic structure of the several nanostructured earth-abundant electrocatalysts including oxide, (oxy)hydroxide, layered double hydroxide, alloy, metal phosphide/phosphate, nitride, sulfide, selenide, carbon containing materials, MOF, core–shell/hetero/hollow structured materials, and materials with vacancies/defects for OER in alkaline environment (including activity: overpotential (η) of ≤200 mV at 10 mA cm−2; stability: ≥100 h; durability: ≥5000 cycles). Then, this review discusses the robust stability of the electrocatalysts for OER towards practical application. Moreover, this review discusses the in situ formation of thin layer on the catalyst surface during OER. In addition, this review discusses the influence of the adsorption energy of the OER intermediates on OER performance of the catalysts. Finally, this review summarizes the various promising strategies for tuning the electronic structure of the electrocatalysts to achieve enhanced performance for OER in alkaline environment.