Nitrogen- and Phosphorus-Doped Biocarbon with Enhanced Electrocatalytic Activity for Oxygen Reduction

Abstract

The oxygen reduction reaction (ORR) at the cathode of fuel cells and metal–air batteries requires efficient electrocatalysts to accelerate its reaction rate due to its sluggish kinetics. Nitrogen- and phosphorus-doped biocarbon has been fabricated via a simple and low-cost biosynthesis method using yeast cells as a precursor. The as-prepared biocarbon exhibits excellent electrocatalytic activity for the ORR. An onset potential of −0.076 V (vs Ag/AgCl) and a negative shift of only about 29 mV in the half-wave potential of the biocarbon as compared to commercial Pt/C (20 wt % Pt on Vulcan XC-72, Johnson Matthey) is achieved. The biocarbon possesses enhanced electron poverty in carbon atoms and a decreasing amount of less electroactive nitrogen and phosphorus dopants due to the biomineralization during the synthesis. The surface gap layer along with the mesopores in the biocarbon increases accessible active sites and facilitates the mass transfer during the ORR. These factors correlate with the high ORR activity of the biocarbon. The results demonstrate that biomineralization plays a critical role in tailoring the structure and the electrocatalytic activity of the biocarbon for ORR.

Fe/Fe3C Nanoparticles Embedded in Nitrogen‐Doped Carbon Nanotubes as Multifunctional Electrocatalysts for Oxygen Catalysis and CO2 Reduction

“…Figure S4 shows the corresponding Koutecky‐Levich plots for Fe/Fe 3 C@NCNT‐750. These plots are linear and parallel, indicating the first‐order dependence of the kinetics of ORR on Fe/Fe 3 C@NCNT‐750 . The number of transferred electrons per oxygen molecule calculated from the K‐L equation is 3.94, indicating a four‐electron process upon catalyzing ORR on Fe/Fe 3 C@NCNT‐750 with water as the main product .…”

Ambient Electrochemical N2 Reduction to NH3 on Nitrogen and Phosphorus Co‐doped Porous Carbon with Trace Iron in Alkaline Electrolytes

“…The P−C and P−O bonds are present in the Fe‐NPC (Figure d), which confirmed the successfully doping of P heteroatoms into the carbon network through thermal pyrolysis. P doping into the carbon network can influence the charge density of adjacent carbon atoms and generate the synergetic effect with N dopants, which are beneficial to the electrocatalytic activity of carbon materials . Thus, it is expected that the N, P co‐doped porous carbon with trace Fe can serve as an efficient electrocatalyst for NRR under ambient conditions.…”

Recent Progress on MOF-Derived Nanomaterials as Advanced Electrocatalysts in Fuel Cells

“…These properties, together with the extraordinary degree of variety in organic and inorganic components, make MOFs materials particularly interesting for application Great efforts have been devoted to develop highly efficient, economical, and stable catalysts for ORR, including advanced Pt alloys, core-shell structures, heteroatom-doped-carbon, and transition metal/metal oxide-carbon composite catalysts (as shown in Figure 1) [10][11][12][13][14][15]. Among the non-noble metal catalysts, transition metal/metal oxide-carbon (e.g., Co/Co 3 O 4 -C, Co-Nx-C, Fe-Nx-C) [16][17][18] and heteroatom-doped-carbon materials (e.g., N-C, NS-C, NP-C) [19][20][21][22][23][24], have been a major focus of research due to their excellent electrocatalytic activity, high stability, and low cost. Particularly, the non-noble metal catalysts fabricated from MOFs precursors have been explored and demonstrate a number of advantages owing to their high specific surface area, porous structure, and abundantly high distribution of active sites.…”

“…Recent pioneering work has indicated that the ORR performance of graphitic carbon may be further improved by co-doping heteroatoms, resulting in a synergistic effect arising from the charge and spin density changes, which are favorable toward O 2 adsorption, electron transfer, and facilitating the ORR performance [49]. This synergistic effect postulates that co-doped carbon materials may be able to achieve higher activity compared to their single atom doped counterparts [22,23,53,54]. By accurately tuning the organic linkers of MOFs component or through reasonable post-treatment methods, multi-doped nanocarbon (e.g., N, P, S-co-doped carbon) and related functional nanomaterials can be designed as ORR electrocatalysts [43][44][45].…”