A Br-regulated transition metal active-sites anchoring and exposure strategy in biomass-derived carbon nanosheets for robust ORR/HER electrocatalysts at all pH values A novel Br-regulated “Transition Metal Active-sites Anchoring and Exposure” (TMAAE) strategy is reported, for the first time, to fabricate a hierarchical porous Co/N-doped bio-carbon bifunctional electrocatalyst (CoTBrPP@bio-C) for all-pH ORR and HER by using a simple one-pot co-pyrolysis over the mushroom (MR) template...