High‐Performance Trifunctional Electrocatalysts Based on FeCo/Co₂P Hybrid Nanoparticles for Zinc–Air Battery and Self‐Powered Overall Water Splitting

Abstract

Currently, it is still a significant challenge to simultaneously boost various reactions by one electrocatalyst with high activity, excellent durability, as well as low cost. Herein, hybrid trifunctional electrocatalysts are explored via a facile one‐pot strategy toward an efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The catalysts are rationally designed to be composed by FeCo nanoparticles encapsuled in graphitic carbon films, Co2P nanoparticles, and N,P‐codoped carbon nanofiber networks. The FeCo nanoparticles and the synergistic effect from Co2P and FeCo nanoparticles make the dominant contributions to the ORR, OER, and HER activities, respectively. Their bifunctional activity parameter (∆E) for ORR and OER is low to 0.77 V, which is much smaller than those of most nonprecious metal catalysts ever reported, and comparable with state‐of‐the‐art Pt/C and RuO2 (0.78 V). Accordingly, the as‐assembled Zn–air battery exhibits a high power density of 154 mW cm−2 with a low charge–discharge voltage gap of 0.83 V (at 10 mA cm−2) and excellent stability. The as‐constructed overall water‐splitting cell achieves a current density of 10 mA cm−2 (at 1.68 V), which is comparable to the best reported trifunctional catalysts.

Coupling NiCo Alloy and CeO2 to Enhance Electrocatalytic Hydrogen Evolution in Alkaline Solution

“…The performance for the NiCo–CeO 2 ||NiCo(OH) x –CeO 2 electrolyzer also outperforms most recently reported electrolyzers based on non‐noble bifunctional electrocatalysts (Figure 5e; Table S4, Supporting Information). [ 45–59 ]…”

“…The performance for the NiCo-CeO 2 ||NiCo(OH) x -CeO 2 electrolyzer also outperforms most recently reported electrolyzers based on non-noble bifunctional electrocatalysts (Figure 5e; Table S4, Supporting Information). [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] The excellent overall water splitting activity of the NiCo-CeO 2 ||NiCo(OH) x -CeO 2 electrolyzer is not only attributed to the high intrinsic catalytic activities of NiCo-CeO 2 / GP and NiCo(OH) x -CeO 2 /GP, but also to the self-supported electrode structure. Due to the in situ growth of active species on conductive substrate, the interface resistances of the self-supported NiCo-CeO 2 /GP and NiCo(OH) x -CeO 2 /GP electrodes are greatly lower than those of the Pt/C(20%)/GP and RuO 2 /GP electrodes by physically coating (Figure S25, Supporting Information), which are conducive to the rapid electron transfer.…”

Contribution of Cation Addition to MnO2 Nanosheets on Stable Co3O4 Nanowires for Aqueous Zinc-Ion Battery

“…XPS results of Figure 5E show that the binding energy of Co does not change much, which indicates that Co 3 O 4 does not take part in electrochemical reactions. Based on the above analysis, the working mechanism of our cathode can be summarized in Figure 5F (Cheng et al, 2016 ; Shi et al, 2020 ). Many studies have also found that Mn 3 O 4 has a tendency of phase transition to a layered MnO 2 in the cycling process (Jabeen et al, 2017 ; Hao et al, 2018 ).…”

A Wet Impregnation Strategy for Advanced FeNi‐Based Electrocatalysts towards Oxygen Evolution

“…The corresponding compounds are also expensive. In particular, their relatively lower stability in alkaline electrolytes also limits their wide application [10–14] …”

“…In particular, their relatively lower stability in alkaline electrolytes also limits their wide application. [10][11][12][13][14] Fe-, Ni-, and Co-based compounds are considered to be the most promising candidates for OER catalysts due to their excellent catalytic performance and low cost. [15][16][17][18][19][20][21] In recent years, there are many studies about these low-cost catalysts.…”