Nanohybrids of B- and N-codoped reduced graphene oxide/CeO2–Co3O4 nanocomposite for efficient water oxidation

Abstract

Transition metal oxides are well known as highly active and durable catalysts for the oxygen evolution reaction (OER). In this work, to enhance the electrocatalytic activity of CeO2 nanostructure in the water oxidation reaction, CeO2/Co3O4 and boron-nitrogen co-doped reduced graphene oxide incorporated (B,N-rGO) into CeO2/Co3O4 with a weight ratio of 3:1 of nanoparticles to graphene oxide were synthesized using co-precipitation and hydrothermal methods, respectively. The prepared materials were studied in detail regarding their crystal structure and morphological properties. The as-prepared materials were used as modified carbon paste electrodes for electrochemical water oxidation in an alkaline solution. The results showed that incorporating graphene oxide network into the nanoparticles structure enhances their OER performance. The material based on CeO2/Co3O4@B,N-rGO hybrid nanocomposite showed excellent OER activity with an overpotential of 410@10 mA cm−2, which is 240 and 140 mV less than that of the single CeO2 and CeO2/Co3O4 samples. Also, CeO2/Co3O4@B,N-rGO displayed the lowest Tafel slope and charge transfer resistance among the other catalysts. Moreover, the proposed catalyst displayed high stability and durability during OER. The enhanced OER performance of the CeO2/Co3O4@B,N-rGO is attributed to several catalytically active sites created by B and N doped rGO in the nanocomposite structure. The high performance of this catalyst results from the synergy of combining CeO2/Co3O4 nanoparticles with a three-dimensional co-doped rGO network.