Robust Mesoporous Manganese Oxide Catalysts for Water Oxidation

Abstract

Inspired by the natural oxygen evolution reaction of Photosystem II, the earth-abundant and inexpensive manganese oxides (MnO x ) have been recognized for their great potential as highly efficient and robust materials for water oxidation reaction (WORs). To date, most of the heterogeneous, synthesized MnO x catalysts still exhibit lower activities for WORs, in comparison to RuO 2 and IrO 2 . Herein, we report a single-step and scalable synthesis method for mesoporous MnO x materials that is developed through a soft-templated method. This method allowed precise control of Mn 3+ -rich Mn 2 O 3 structure as well as pore sizes and crystallinity of these mesoporous MnO x . These catalysts were investigated for both photochemical and electrochemical water oxidation, and they presented a superior activity for water oxidation. The highest turnover frequency of 1.05 × 10 –3 s –1 was obtained, which is comparable with those for precious metal oxide based catalysts (RuO 2 and IrO 2 ). Our results illustrate a guideline to the design and synthesis of inexpensive and highly active heterogeneous catalysts for water oxidation.