One-step synthesis of boron and nitrogen-dual-self-doped graphene sheets as non-metal catalysts for oxygen reduction reaction

Direct anchoring of platinum nanoparticles on nitrogen and phosphorus-dual-doped carbon nanotube arrays for oxygen reduction reaction

“…Fig. 6b shows the well-known corrected Tafel plots [40] for ORR on the catalysts. The catalysts showed slopes of -60 mV per decade at low overpotential and -120 mV per decade at high overpotential, suggesting that they have the same reaction mechanism [45,46].…”

“…The peaks at 398.5, 399.2 and 401.2 eV are attributed to pyridinic nitrogen, pyrrolic nitrogen and graphitic nitrogen, respectively[34,38]. The pyridinic-N with a lone electron pair in the plane of carbon matrix induces the side-on adsorption during chemisorption of oxygen on the surface of the electrocatalyst, which effectively weakens the O-O bond and facilitates the reduction of O 2[39,40]. The graphitic-N atoms could be ORR active and catalyse the ORR through a 'direct four-electron' pathway.…”

Heteroatom substituted and decorated graphene: preparation and applications

“…228,229 Specifically, Xia group 55 reported a catalyst-free BG with the B content of 3.2 %, which exhibited a one-step process for ORR with an onset potential at -0.05 V, long-term stability in alkaline electrolytes, and good tolerance to methanol and CO (Figure 8a- due to a synergetic effect arising from the N and B co-doping. 165 In the work of Shen group, 166 the as-prepared BNG shows a remarkable activity and high stability for the ORR. The BNG samples were demonstrated to show ORR electrocatalytic activities even better than the commercial Pt/C electrocatalyst.…”

“…Obviously, the N-and B-doping level depends strongly on the annealing temperature and time in such methods.In particular, Zhu group 164 obtained the NBG hierarchical framework through a combined microwave-activated chemical-thermal treatment, the sample has a higher pore size than that of the sample prepared using conventional heating method, this might be ascribed to the thermally unstable oxygen-containing groups on graphene sheets generated under microwave treatment. Furthermore, In the work of group Shen,166 the formation of the BNG was accomplished using borane-tert-butylamine complex as the only one precursor impregnated with a certain amount of cobalt ions. For example, Kalita et al165 obtained BNG by the reaction of CO 2 with NH 3 BH 3 in two sequential processes including carbon fixation and pyrolysis.…”

N-, P- and S-tridoped graphene as metal-free electrocatalyst for oxygen reduction reaction

“…The cathodic oxygen reduction reaction (ORR) is an important process in fuel cells, which could affect the chemical-electrical energy conversion efficiency significantly [3]. But the high overpotential and slow kinetics for the ORR have limited the large scale commercial applications of fuel cells [4,5]. As well known, Pt and Pt based materials have been regarded as the most active catalysts for ORR in fuel cells owing to their relatively low overpotential and high current density, however, they still suffer from high cost, CO poisoning, low tolerance to methanol and poor stability [6,7].…”