Concave Bi2WO6 nanoplates with oxygen vacancies achieving enhanced electrocatalytic oxygen evolution in near-neutral water

Abstract

Developing highly efficient and inexpensive oxygen evolution reaction (OER) electrocatalysts in near-neutral water is of paramount importance for many practical applications. Herein, we report that Bi₂WO₆ concave nanoplates (CNPs) with oxygen vacancies enable the electrocatalytic OER under neutral conditions with high activity and good durability. To the best of our knowledge, this is the first example on W-based electrocatalysts containing no first-row transition metal or precious metal elements for the OER in near-neutral water. Experimental results and first-principles calculations revealed that the presence of oxygen vacancies in Bi₂WO₆ CNPs could significantly decrease the charge-transfer resistance and adsorption barrier of H₂O molecules in the process of electrochemistry, thus benefiting the improvement of OER activity. The fabrication of concave surfaces with high energy facets could further enhance the OER activity of the Bi₂WO₆ NP electrocatalysts. As a result, the synergistic effect of oxygen vacancies and concave surfaces led to impressive performance of Bi₂WO₆ CNPs for the OER, which is comparable to the best electrocatalysts among known inorganic non-precious metal compounds. The present strategy on the combination of defect and crystal facet engineering could open a new avenue to design new and highly efficient OER electrocatalysts.