Single-atom catalysts (SACs) within carbon matrix became one of the most promising alternatives to noble metal-based catalysts for oxygen reduction reaction (ORR). Although SACs have significant benefits in reducing the total catalyst cost, it also has the disadvantages of weak interaction between atoms and poor stability. Hence, there is still much room for improvement for the catalyst activity. In response, we designed a Fe-Co-Pt ternary metal single atom catalyst anchored on covalent organic framework (COF)-derived N-doped carbon nanospheres (Pt, Fe, Co/N-C). Due to effective charge transfer between Pt single atom and neighboring Fe-Co components, an intense electron interaction can be established within the Pt, Fe, Co/N-C catalyst. This is beneficial for enhancing charge transfer efficiency, modulating d electronic structure of Pt center and weakening oxygen intermediate adsorption, thus distinctly accelerating ORR catalytic kinetics. As expected, the half-wave potential of Pt, Fe, Co/N-C was 0.845 V, much higher than those of commercial 20 wt% Pt/C (0.835 V), Pt/N-C (0.79 V) and Fe, Co/N-C (0.81 V) counterparts. Moreover, the Pt, Fe, Co/N-C catalyst demonstrated much-improved cycling stability and methanol tolerance.
Lithium-Sulfur batteries (Li-S batteries) have gained great interest in next-generation energy storage systems due to their high energy density and low-cost sulfur cathodes. There is, however, a serious obstacle in the commercial application of Li-S batteries due to the poor kinetics of the redox process at the sulfur cathode and the “shuttle effect” caused by lithium polysulfide (LiPSs). Herein, we report the synthesis of a sulfur cathode host material that can drastically inhibit the “shuttle effect” and catalyze the conversion of LiPSs by a simple electrostatic spray technique, namely, cobalt (Co) nanoclusters doped with N-containing porous carbon spheres (Co/N-PCSs). The results show that Co/N-PCSs has catalytic activity for the transformation of liquid LiPSs to solid Li2S and alleviates the notorious “shuttle effect.” This new sulfur cathode exhibits stable running for 300 cycles accompanied by a capacity of 650 mAh g−1 at a current density of 1 C, a capacity fading rate of 0.051% per cycle, and a Coulombic efficiency maintained at close to 100%. The results demonstrate that Co/N-PCSs offers the possibility of practical applications for high-performance Li-S batteries.
It is critical and challenging to develop high performance transition metal phosphides (TMPs) electrocatalysts for oxygen evolution reaction (OER) to address fossil energy shortages. Herein, we report the synthesis of Co2P embedded in N-doped porous carbon (Co2P@N-C) via a facile one-step strategy. The obtained catalyst exhibits a lower overpotential of 352 mV for OER at a current density of 10 mA cm−2 and a small Tafel slope of 84.6 mV dec−1, with long-time reliable stability. The excellent electrocatalytic performance of Co2P@N-C can be mainly owed to the synergistic effect between the Co2P and highly conductive N-C substrate, which not only affords rich exposed active sites but also promotes faster charge transfer, thus significantly promoting OER process. This work presents a promising and industrially applicable synthetic strategy for the rational design of high performance nonnoble metal electrocatalysts with enhanced OER performance.