Silver-Perovskite Hybrid Electrocatalysts for Oxygen Reduction Reaction in Alkaline Media

Abstract

Developing a low-cost, and highly-efficient catalysts for improving oxygen reduction reaction (ORR) is imperative to the energy storage and conversion device. Here, we synthesized Ag/La 0.6 Sr 0.4 CoO 3-δ (Ag/LSC) composites by decorating LSC with Ag using the electroless technique. As a result, the LSC was homogenously overlaid with Ag nanoparticles. The derived Ag/LSC composites possessed a relatively higher specific surface area than pure LSC and Ag. The Co-O-Ag bonds in the composites contribute substantial electrons transferred from Ag to Co element, resulting in the unique electronic structures and strong electronic interaction between Ag and LSC. The significant improvements of ORR activity in alkaline solution at room temperature can be observed in Ag/LSC composites compared to the pure Ag and LSC. The composites with optimal Ag loading (50 wt%) showed best ORR activity among all the composites according to the half-wave potential and diffusion limiting current density. The presented strategy of silver surface modification via electroless process can provide effective routes for designing high performance metal oxide (e.g. perovskite) composite electrocatalysts.

The Synergistic Effect Accelerates the Oxygen Reduction/Evolution Reaction in a Zn-Air Battery

“…We consider that the surface electronic transfer in the Ag-SSC composite was optimized by adding Ag into the SSC perovskite oxide, thereby leading to an increased ORR activity. A similar effect of the electron transfer effect has also been previously reported in other systems (Liu and Mustain, 2013; Han et al, 2014; Wang et al, 2018).…”

“…The Ag particle was fully distributed into the SSC nanoparticles with sizes of 1~10 μm (Figure 2a). However, the Ag particle had an irregular shape (Figure 2a), and the distribution of Ag in the SSC particles was demonstrated to be uneven (Figure 2c), which will adversely affect the activity of the composite catalyst (Guo et al, 2010; Park et al, 2015; Wang et al, 2018). In addition, the content of Ag in Ag-SSC was calculated based on the X-ray energy dispersive spectroscopy (EDX) results and listed in Table 1.…”

Oxygen Reduction Reaction on Silver Catalysts in Alkaline Media: a Minireview

“…Wang et al. optimised the composition of the Ag/La 0.6 Sr 0.4 CoO 3‐δ composite catalysts and demonstrated that 50 wt% Ag is needed to have the best results . However, even 50 wt% Ag catalyst still has a more negative half‐wave potential for O 2 reduction than commercial Pt/C.…”

“…[97] Wang et al optimised the composition of the Ag/La 0.6 Sr 0.4 CoO 3-d composite catalysts and demonstrated that 50 wt% Ag is needed to have the best results. [98] However, even 50 wt% Ag catalyst still has a more negative half-wave potential for O 2 reduction than commercial Pt/C. Gong et al achieved the ORR efficiency comparable to that of commercial Pt/C catalyst with Ag-WC/C catalyst in a microbial fuel cell as a result of synergistic effect between Ag and WC.…”

Nonnoble metal oxides for high‐performance Zn‐air batteries: Design strategies and future challenges

“…Combination of the active metal or metal oxides with perovskite oxides has been regarded as an available approach to improve ORR and OER activity. For instance, Zhou et al prepared Ag/La 0.6 Sr 0.4 CoO 3‐δ composites via decorating LSC with Ag 121 . The composite showed a comparatively larger specific surface area than both simple LSC and Ag because LSC overlaid homogenously Ag nanoparticles.…”