Biomass-derived precious metal-free porous carbon: Ca-N,P-doped carbon materials and its electrocatalytic properties

Highlights: : • Ca@NP₆C₄ catalyst derived from biomass hydrogel was designed and synthesized. • Catalyst has 3D hierarchical porous structure and high content of nitrogen (29.71 wt%). • Ca@NP₆C₄ showed positive onset potential, excellent durability and methanol tolerance. • For MOR, Pt/Ca@NP₆C₄ exhibited impressive catalytic activity and stability. -- Abstract: The search for non-noble metal catalysts drive from biomass materials for oxygen reduction reactions (ORR) is highly desirable but challenging. Here, we have designed and synthesized three-dimensional hierarchical porous Ca-modified nitrogen and phosphorus co-doped carbon materials (Ca@NP₆C₄) derived from biomass hydrogel. Notably, the resulting Ca@NP₆C₄ material has high content of nitrogen (29.71 wt%)and relatively high content percentage of pyridinic and graphitic nitrogen. As an efficient non-noble metal electrocatalyst, Ca@NP₆C₄ exhibits a high onset potential (0.94 V vs RHE) and a four-electron pathway for oxygen reduction reaction as well as good durability and outstanding methanol poisoning tolerance. Besides, it also performs as a good support for Pt particles (NPs). Pt/Ca@NP₆C₄ catalyst displayed remarkable catalytic performance and high stability for methanol electrooxidation reaction in acid medium. This work provides a feasible approach to develop cost-effective and highly efficient non-precious metal electrochemical catalysts for oxygen reduction.