Electrodeposition of sulfur-engineered amorphous nickel hydroxides on MIL-53(Fe) nanosheets to accelerate the oxygen evolution reaction.

Exploring Earth-abundant electrocatalysts that are highly efficient, low cost, and stable for the oxygen evolution reaction (OER) are critical to energy storage and water splitting. Metal-organic frameworks (MOFs) have been regarded as superior electrocatalysts due to their atomically dispersed metal ions. Currently, MOFs have been widely studied as templates to fabricate electrocatalysts through thermal annealing. Here, we report a novel synthetic approach to fabricate a Ni-S/MIL-53(Fe) electrode by electrodepositing sulfur-engineered amorphous nickel hydroxides on MIL-53(Fe) nanosheets. The obtained binder-free, self-supported Ni-S/MIL-53(Fe) shows high OER activity with overpotentials of 256 and 298 mV to achieve 10 and 100 mA cm-2, respectively. Moreover, it also exhibits excellent electrochemical stability with no obvious degradation at 100 mA cm-2 for at least 40 h. The new findings may pave a new avenue for designing and fabricating low-cost catalysts with high efficiency for electrochemical applications.