Directly ball milling red phosphorus and expended graphite for oxygen evolution reaction

Oxygen evolution reaction (OER) electmcatalysis plays an important role in clean and renewable energy conversion. Designing high-performance OER electrocatalyst is key to the high electrochemical activity. Noblemetal-free electrochemical OER electmcatalysts become the major trend. Herein, we report a facile ballmilling method to prepare red phosphorus (BP)-black phosphorus (BP)/expended graphite (EG) toward OER electrocatalysis. By virtue of the high temperature and shearing force generated in the ball-milling process, a portion of red phosphorus can be in-situ transferred into chemical active BP and formed the RP-BP heterostructure. Meantime, the EG flakes are cut and exfoliated into defect-rich graphene nanosheets and thin EG flakes, reacting with the RP-BP heterostructure through P-C and P-O-C bonds. The hybridization of RP-BP and EG improves the electroconductivity and facilitate more active electrocatalytic sites toward OER. The results demonstrate that RP-BP/EG heterostructure shows good OER performance with a low overpotential of 328 mV vs. RHE) at a current density of 10 mA cm(-2), lower than commercial IrO2 (330 mV vs. RHE, 10 mA cm(-2)). A very small Tafel slope of 58 mV.dec(-1) indicates the high electron transmission on the RP-BP/EG catalyst. The stable structure of RP-BP/EG provides the long-term durability of the RP-BP/EG catalysts in OER.