▎ 摘　　要

Compared with the traditional heteroatom doping, employing heterostructure is a new modulating approach for carbon-based electrocatalysts. Herein, a facile ball milling-assisted route is proposed to synthesize porous carbon materials composed of abundant graphene/hexagonal boron nitride (G/h-BN) heterostructures. Metal Ni powder and nanoscale h-BN sheets are used as a catalytic substrate/hard template and "nucleation seed" for the formation of the heterostructure, respectively. As-prepared G/h-BN heterostructures exhibit enhanced electrocatalytic activity toward H2O2 generation with 86%-95% selectivity at the range of 0.45-0.75 V versus reversible hydrogen electrode (RHE) and a positive onset potential of 0.79 versus RHE (defined at a ring current density of 0.3 mA cm(-2)) in the alkaline solution. In a flow cell, G/h-BN heterostructured electrocatalyst has a H2O2 production rate of up to 762 mmol g(catalyst)(-1) h(-1) and Faradaic efficiency of over 75% during 12 h testing, superior to the reported carbon-based electrocatalysts. The density functional theory simulation suggests that the B atoms at the interface of the G/h-BN heterostructure are the key active sites. This research provides a new route to activate carbon catalysts toward highly active and selective O-2-to-H2O2 conversion.