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

A facile synthesis of hierarchically porous carbon (WB-AC) from wheat bran waste is reported. The WB-AC carbon has a large surface area (757 m² g⁻¹), and the total pore volume (0.3696 cm³ g⁻¹) showed selective CO₂ uptake, rapid dye removal, and high electrochemical activity (OER/HER)

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.

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