Abstract
The construction of MnCo−CH@NiFe−OH p-n junction modifies the electron property and therefore leads to a greatly enhanced electrocatalytic activity towards the overall water splitting.
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•The MnCo−CH@NiFe−OH p-n junction was constructed.•DFT calculation reveals the formation of p-n junction enhance the OER energetics.•The p-n junction shows significantly enhanced OER performance that is ∼10 times that of NiFe−OH.•The p-n junction based electrolyzer requires a low cell voltage of only 1.57 V to reach 10 mA cm−2.
NiFe oxyhydroxide (NiFe−OH) has shown promising electrocatalytic oxygen evolution reaction (OER) activity. Here we suggest that the performance of NiFe−OH can be further enhanced by constructing pn junction. Using MnCo carbonate hydroxide (MnCo−CH)@NiFe−OH pn junction as a demonstration, we show that upon the construction of pn junction, the electrons flow from n-type NiFe−OH to MnCo−CH, which consequently generates a positively charged region on NiFe−OH. The density function theory calculation reveals that such an electronic property change results in an improved OER energetics. As a result, the MnCo−CH@NiFe−OH pn junction shows significantly enhanced OER performance that is ∼10 and ∼500 times that of NiFe−OH and MnCo−CH (in terms of the OER currents at the overpotential of 270 mV), respectively. Moreover, the pn junction also shows a greatly boosted hydrogen evolution reaction (HER) and therefore the overall water electrolysis activity that outperforms the Pt/C||RuO2 catalysts.