Ceria Boosting on In Situ Nitrogen-Doped Graphene Oxide for Efficient Bifunctional ORR/OER Activity

Abstract

In the present work, a highly efficient and excellent electrocatalyst material for bifunctional oxygen reduction/evolution reaction (ORR/OER) was synthesized using the microwave-assisted hydrothermal method. In brief, ultrafine hexagonal cerium oxide (CeO2) nanoparticles were tailored on the layered surface of in situ nitrogen-doped graphene oxide (NGO) sheets. The nanocomposites exhibited a high anodic onset potential of 0.925 V vs. RHE for ORR activity and 1.2 V for OER activity with a very high current density in 0.5 M KOH. The influence of oxygen cluster on Ce3+/Ce4+ ion decoration on outward/inward in situ nitrogen-coupled GO enhanced the physicochemical properties of composites and in turn increased electron transferability. The microwave-assisted hydrothermal coupling technique provides a higher density, active sites on CeO2@NGO composites, and oxygen deficiency structures in ultrafine Ce-O particles and boosts higher charge transferability in the composites. It is believed that the physical states of Ce-N- C, Ce-C=O, and a higher amount of oxygen participation with ceria increase the density of composites that in turn increases the efficiency. N-doped graphene oxide promotes high current conduction and rapid electron transferability while reducing the external transport resistance in oxygen electrocatalysis by sufficient mass transfer through in-built channels. This study may provide insights into the knowledge of Ce-enabled bifunctional activity to guide the design of a robust catalyst for electrochemical performance.

Cerium-Based Electrocatalysts for Oxygen Evolution/Reduction Reactions: Progress and Perspectives

“…At present, the method to optimize this problem mainly entails the combination with the conductive carrier, although the lack of conductive carriers is a new problem. Byrappa et al synthesized an efficient and excellent bifunctional oxygen reduction/precipitation reaction (ORR/OER) electrocatalyst material by combining CeO 2 with nitrogen-doped graphene (NGO) via the microwave-assisted hydrothermal coupling technique [ 112 ]. Among them, nitrogen-doped graphene oxide promotes high current conduction and fast electron transfer, while the adequate mass transfer through the built-in channels reduces the external transmission resistance in oxygen electrocatalysis.…”

“…Even the precious metal Pt- and Ru-based catalysts have unsatisfactory bifunctional catalytic properties. Byrappa et al synthesized an efficient and excellent bifunctional oxygen reduction/precipitation reaction (ORR/OER) electrocatalyst material via the microwave-assisted hydrothermal method [ 112 ]. Microwave-assisted hydrothermal coupling technology provides a higher density of active sites on CeO 2 @NGO composites.…”

Metal oxide stabilized zirconia modified bio-derived carbon nanosheets as efficient electrocatalysts for oxygen evolution reaction

“…Furthermore, Tafel slope analysis was performed to evaluate the kinetic mechanism of the electrocatalyst during the OER process [26][27][28][29]. The plot of the Tafel slopes shown in Fig.…”

“…It's observed that the overpotential kept increasing for 3.5 h, then remained approximately stable for another 7 h without any observable uctuations. As time increases, the overpotential is increased again for another 5 h until it reached a stable state after 15 h and an overpotential of 160 mV up to 21 h. This indicates the long-term stability and durability performance of CSZ 1000/mC 2% electrocatalyst which con rms the rapid charge transfer, facile gas adsorption and diffusion [26][27][28][29][30][31][32][33][34][35].…”

Insights into the origin of Co-based bimetallic catalysts with a para-structure exhibiting ORR and OER bifunctional activities

“…N-S and Mn co-doped two-dimensional graphene nanosheets were synthesized by Guan et al 38 and the catalyst showed the OER overpotential as low as 296 mV. Wang et al 39 Recently, research on catalysts with the bifunctional activities of ORRs and OERs has gradually become a hotspot, [40][41][42][43][44] in which Co and Fe-based catalysts have attracted the most attention. Wang et al 45 investigated the effect of the coordination number of N atoms on the performance of Co-doped graphene catalysts.…”