Synthesis of Co2Ni/reduced graphene oxide composite aerogels as efficient hydrogen evolution catalysts

H-2 is promising clean energy and electrochemical hydrogen evolution reaction offers a sustainable route compared with traditional methane steam reforming. In this work, highly porous Co2Ni and Co2Ni/reduced graphene oxide composite aerogels are prepared by a simple in-situ reduction-gelation method in an aqueous solution. The synthesis starts with Co-Ni hydrogel which is prepared by mixing a strong reduction agent NaBH4 with the corresponding metal ions, while graphene oxide is reduced simultaneously in the gelation process. After supercritical drying, composite aerogels composed with interconnected binary Co2Ni nanoparticles network and reduced graphene oxide sheets are obtained. Such optimized composite alloy/reduced graphene oxide aerogels show good hydrogen evolution catalytic activity in alkaline electrolytes, which is highlighted by the low on-set overpotential (143 mV@10 mA/cm(2)) and small Tafel slope (85 mV/dec). [GRAPHICS] .

Automated summary

This study presents a simple method for synthesizing highly porous Co2Ni and Co2Ni/reduced graphene oxide composite aerogels in an aqueous solution. The composite materials show excellent catalytic activity for hydrogen evolution in alkaline electrolytes.