3D printing electro-catalysts for hydrogen production

The rising pollution and depleting fossils fuels urgently demand alternative renewable sources of energy. Hydrogen is one of the promising fuels with zero pollution which can be abundantly produced by electrolysis of water. But, the challenge is to produce h ydrogen with least energy consumption via renewable sources from electrolysis of water. This has led to extensive research in synthesis of novel low-cost catalysts with high performance. However, there is still a need for a robust catalyst with low cost and long-term stabilities. Herein we demonstrate an alternative approach to synthesize these catalysts in which nickel-based catalysts are synthesized by extrusion-based 3D printing (3DP). The catalyst precursor is initially 3D printed by nickel-based powder. The precursor is oxidized and further sulfurized to convert them to catalysts with remarkable performance. The oxidized 3DP nickel (3DP nickel @NiO) shows remarkable performance for hydrogen evolution reaction (HER) with a low overpotential of 113.56 mV at 10 mA cm^-2. The sulfurized 3DP nickel (3DP nickel@NiS) can act as a bifunctional catalyst with a low overpotential of 166.17 mV at 10 mA cm^-2 for HER and 220 mV at 20 mA cm^-2 for oxygen evolution reaction (OER). Thus, this work demonstrates 3D printing as a promising way of synthesis to produce robust, binder-free catalysts in industries for mass scale application.