Exploring Sustainable Hydrogen Production from Alkaline Fresh and Seawater Using Natural Ore Derived 2D Bi ₂ S ₃

Abstract Water electrolysis for hydrogen, though widely studied, presents exciting opportunities for improvement beyond conventional energy and cost‐intensive catalysts. Natural ores, being abundant and readily available, hold immense promise as sustainable sources of alternative energy materials. Here, this method offers a simple and low‐cost route, not only to make 2D materials but also to develop electrocatalysts from earth‐abundant ores. Synthesis of 2D Bi ₂ S ₃ is demonstrated via Liquid phase exfoliation (LPE) of the naturally abundant bismuthinite ore. Sustainability of such 2D Bi ₂ S ₃ is explored for hydrogen evolution reaction (HER) from alkaline fresh and simulated seawater. The exfoliated Bi ₂ S ₃ exhibits an overpotential of 693 and 678 mV at 10 mA cm ^{‐ 2} in alkaline fresh and simulated seawater with a durability up to 40 h. From Density Functional Theory (DFT) based First‐principles calculations, sulfur sites are found to bind H‐intermediates strongly in comparison with bismuth sites. Sustainability is further investigated by life cycle calculation. A lower carbon footprint of the 2D Bi ₂ S ₃ catalyst is observed under both alkaline fresh (21.13 kg CO ₂ eq kg ⁻¹ H ₂ ) and simulated seawater (15.56 kg _CO2eq kg ⁻¹ H ₂ ). This work extends a sustainable strategy to utilize earth‐abundant natural source for fabricating efficient and durable HER electrocatalysts for future fuel.