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

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 CO₂ capture capacity with good CO₂ /N₂ 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 m² g^-1 ) and total pore volume (0.3696 cm³ g^-1 ) result from N₂ activation contributing to selective CO₂ 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.