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The exploration of high-performance and earth-abundant water oxidation catalysts operating under mild conditions is highly attractive and challenging. In this communication, core-shell CoFe 2 O 4 @Co-Fe-Bi nanoarray on carbon cloth (CoFe 2 O 4 @Co-Fe-Bi/CC) was successfully fabricated by in situ surface amorphization of CoFe 2 O 4 nanoarray on CC (CoFe 2 O 4 /CC). As a 3D water oxidation electrode, CoFe 2 O 4 @Co-Fe-Bi/CC shows outstanding activity with an overpotential of 460 mV to drive a geometrical catalytic current density of 10 mA cm -2 in 0.1 M potassium borate (pH 9.2). Notably, it also demonstrates superior long-term durability for at least 20 h with 96% Faradic efficiency. Density functional theory calculations indicate that the conversion from OOH* to O 2 is the rate-limiting step and the high water oxidation activity of CoFe 2 O 4 @Co-Fe-Bi/CC is associated with the lower free energy of 1.84 eV on a Co-Fe-Bi shell.

In this Communication, cobalt phosphate (Co-Pi) has been successfully developed on a Co(CO 3 ) 0.5 (OH)·0.11H 2 O nanoarray (CCH NA) on Ti mesh in neutral phosphate-buffered solution (PBS) via in situ electrochemical surface derivation. The resulting core@shell structured CCH@Co-Pi NA/Ti exhibits remarkable activity toward water oxidation with the need of an overpotential of 460 mV to achieve a geometrical catalytic current density of 10 mA cm -2 in 0.1 M PBS, with a high turnover frequency of and long-term electrochemical stability.

SnO(2) nanorods with specific growth directions, [101] or [001], were fabricated on α-Fe(2)O(3) substrates via a simple hydrothermal method. The growth behavior of SnO(2) nanorods is facet-selective. Both {11 ̅20} and {10 ̅10} facets of α-Fe(2)O(3) are favorable to direct the growth of SnO(2) nanorods. The correlation between the crystallographic orientation of SnO(2) and the facets of α-Fe(2)O(3) is characterized by TEM observations and investigated on the basis of the interfacial lattice compatibility. Furthermore, the distribution and coordination of oxygen atoms at the interface of α-Fe(2)O(3)-SnO(2) heterostructure are analyzed, which reveals that only slight deviations from their original equilibrium positions are allowed for the formation of heterogeneous interface. And this lower energy activated interfacial construction is beneficial to the feasibility and stability of heterostructures.