Electrocatalytic water splitting to produce hydrogen comprises the hydrogen and oxygen evolution half reactions (HER and OER), with the latter as the bottleneck process. Thus, enhancing the OER performance and understanding the mechanism are critically important. Herein, we report a strategy of OER enhancement by utilizing gold nanoclusters to form cluster/CoSe2 composites, which exhibit largely enhanced OER activity in alkaline solutions. The Au25/CoSe2 composite affords a current density of 10 mA cm−2 at a smaller overpotential of ~0.43 V (c.f. CoSe2: ~0.52 V). The ligand effect and gold cluster size-dependence can also tune the catalytic performance of the composites. Based upon XPS analysis and DFT simulations, we attribute the activity enhancement to electronic interactions between nanocluster and CoSe2, which favors the formation of the important intermediate (OOH) as well as the desorption of the resultant oxygen molecules over Aun/CoSe2 composites in the process of water oxidation. Such an atomic level understanding may provide some guidelines for design of OER catalysts.

Gold nanoclusters promote electrocatalytic water oxidation at the nanocluster/CoSe2 interface

254th National Meeting (2017)

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