Hierarchical Porous Activated Carbon from Wheat Bran Agro‐Waste: Applications in Carbon Dioxide Capture, Dye Removal, Oxygen and Hydrogen Evolution Reactions

Abstract

Abstract This work reports an efficient method for facile synthesis of hierarchically porous carbon (WB‐AC) utilizing wheat bran waste. Obtained carbon showed 2.47 mmol g −1 CO 2 capture capacity with good CO 2 /N 2 selectivity and 27.35 to 29.90 kJ mol −1 isosteric heat of adsorption. Rapid removal of MO dye was observed with a capacity of ~555 mg g −1 . Moreover, WB‐AC demonstrated a good OER activity with 0.35 V low overpotential at 5 mA cm −2 and a Tafel slope of 115 mV dec −1 . It also exhibited high electrocatalytic HER activity with 57 mV overpotential at 10 mA cm −2 and a Tafel slope of 82.6 mV dec −1 . The large SSA (757 m 2 g −1 ) and total pore volume (0.3696 cm 3 g −1 ) result from N 2 activation contributing to selective CO 2 uptake, high and rapid dye removal capacity and superior electrochemical activity (OER/HER), suggesting the use of WB‐AC as cost effective adsorbent and metal free electrocatalyst.