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.

Oxidatively Electrodeposited Thin-Film Transition Metal (Oxy)hydroxides as Oxygen Evolution Catalysts

“…2,6,7 In recent years, the development of inexpensive metal oxides as catalysts for OER in alkaline solutions has generated renewed interests. [8][9][10][11] A number of such catalysts are reported to be highly active, surpassing IrO x and Ru-O x . 12,13 On a molecular level, the activity of a catalyst is best characterized by its apparent turnover frequency (TOF).…”

Momentum-dependent band spin splitting in semiconducting MnO2: a density functional calculation

“…It is natural to presume that the first stage candidatematerials of the devices for artificial photosynthesis consist of solid state catalysts such as manganese oxides. In fact, there are recent experimental observations of the oxygen evolution of manganese oxides [18][19][20][21] and related substances. [22][23][24] In the present work, we systematically investigate the electronic states of stoichiometric manganese dioxides (MnO 2 ) using firstprinciples calculations as a first step toward the investigation of such materials.…”

Reinvestigation of Water Oxidation Catalyzed by a Dinuclear Cobalt Polypyridine Complex: Identification of CoOx as a Real Heterogeneous Catalyst

“…3 Since OER is associated with the transfer of multiple electrons/protons and O-O bond formation in a high energy barrier process, it becomes kinetically slow and leads to significant consumption of overpotential in the water-splitting process. 4 Thus the design and synthesis of efficient water oxidation catalysts (WOCs) based on earth-abundant elements [5][6][7][8][9][10][11][12][13][14][15][16][17][18] remain great challenge. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 Recently, cobalt-based WOCs have been extensively investigated for their remarkable performance, [19][20][21][22][23][24] in which soluble cobalt complexes as homogeneous WOCs 11,[25]…”