A non-traditional biomass-derived N-, P- and S- ternary self-doped 3D multichannel carbon ORR electrocatalyst

Synthesis of high-efficiency and low-cost electrocatalysts for oxygen reduction reaction (ORR) is currently one of the main targets for the commercialization of fuel cells. In this work, a non-traditional N (5.43%), P (0.71%), and S (0.30%) ternary self-doped 3D multichannel carbon ORR electrocatalyst derived from spinach leave is synthesized for the first time by one-step annealing technology. The as-synthesized electrocatalyst (S-850) successfully makes up for the shortboard of traditional biomass-derived catalysts, that is, solid micron-block and less heteroatomic species, which mainly attributes to the loose mesophyll cell space, various plant proteins, and chlorophyll in the spinach leaves. Based on the above unique multichannel porous structure and ternary heteroatom doping, S-850 exhibits higher limiting diffusion current density of 5.19 mA cm-2 @ 0.5V, durability, and CO/methanol-tolerant than that of commercial 20% Pt/C (5.10 mA cm-2 @ 0.5V) in O2-saturated 0.1 M KOH solution. This work also combines with density functional theory (DFT), further revealing the mechanism of N, P, and S ternary self-doping in spinach leaves-derived ORR catalysts. Considering the availability of spinach leaves around the world, spinach leave-derived carbon material may also be extended to other applications, such as supercapacitors, sensors, and metal-air batteries.