ZIF-L-Co@carbon fiber paper composite derived Co/Co3O4@C electrocatalyst for ORR in alkali/acidic media and overall seawater splitting.

Green and clean energy technologies, including fuel cells, metal-air batteries, water splitting et al., are becoming more significant for our lives. Oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are key reaction processes for fuel cells, metal-air batteries and water splitting. Therefore, it is highly desirable to design a multifunctional catalyst, which owns catalytic performance under a widely applied range. Herein, we demonstrate a novel multifunctional catalyst (Co/Co 3 O 4 @C) by carbonizing a composite material constructed of zeolite imidazolate framework and carbon fiber paper (ZIF-L-Co@CP). It is a carbon-based material containing metallic Co and Co 3 O 4 as a low-cost and effective catalyst toward the ORR and overall water splitting. For ORR, the Co/Co 3 O 4 @C catalyst shows high half-wave potential in both alkaline and acidic media, 0.823 V for 0.1 M KOH and 0.672 V for 0.1 M HClO 4. More importantly, it exhibits good catalytic activities of hydrogen and oxygen evolutions to perform overall splitting in actual seawater. The Co/Co 3 O 4 @C catalyst was prepared by using a composite of ZIF-L-Co nanosheets grown on CP as the precursor, which not only shows excellent activity for ORR in both alkaline and acidic solutions, but also has good ability for overall actual seawater splitting. Image 1 • E 1/2 (0.823 V) of Co/Co 3 O 4 @C catalyst is close to Pt/C in 0.1 M KOH for ORR. • Co/Co 3 O 4 @C catalyst shows excellent ORR performance in 0.1 M KOH and 0.1 M HClO 4. • Co/Co 3 O 4 @C is a good catalyst for overall water splitting in actual seawater. [ABSTRACT FROM AUTHOR]