Scalable cellulose-sponsored functionalized carbon nanorods induced by cobalt for efficient overall water splitting

A balanced design of cheaper, durable, and highly active electrocatalysts for large scale and sustainable hydrogen production is crucial for the emerging hydrogen economy. Herein, a scalable method is implemented to design a very active heteroatom cofunctionalized carbon nanorods with bifunctional electrocatalytic activity via structural transformation of the cellulose fibers from waste tissue paper. Cobalt (Co) is used as both a promoter-catalyst to induce structural evolution of the nanorods, and a self-doped catalyst moiety by coupling with sulfur and nitrogen to enhance the electrocatalytic properties. The obtained catalyst (Co₉S₈@Co-N/C nanorods) displays high hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity, resulting in a small overall water splitting potential of 1.61 V@10 mA cm⁻² and high electrochemical stability for over 70 h. This synthesis approach is further demonstrated to be very suitable for implementation toward large-scale application and can reproduce consistent catalytic properties, which are highly desirable for mass hydrogen production.