The influence of mesopore size distributions on the electrochemical activity and two-electron selectivity of the oxygen reduction reaction in nitrogen-doped and CoOx-loaded activated carbon

In this study, as catalysts for the ORR, two kinds of activated carbon (AC) with different mesopore size distributions are modified by nitrogen (N)-doping and cobalt oxide (CoOx)-loading treatment. It can be concluded that pyridinic-N and pyrrolic-N (48.94%) are more easily formed on the AC with narrow mesopore size distributions (AC-1, 2–5 nm), however, graphite-N (63.9%) are more easily formed on the AC with broad mesopore size distributions (AC-2, 5–15 nm). Furthermore, Co3O4 and CoO is the predominant crystal loaded onto the modified AC-1 and modified AC-2, respectively. The modified AC-1 has an extremely high propensity for a four-electron ORR pathway, while the modified AC-2 has an extremely high propensity for a two-electron ORR pathway. In addition, a rolling activated carbon electrode (RACE) with low-cost and high-efficiency is fabricated by modified AC-2. The H2O2 electro-synthesis rate and current efficiency for the RACE are 0.236 ± 0.025 mg/h/mA/cm2 and 63.25 ± 6.79%, respectively.Graphical abstract
Source: Journal of Electroanalytical Chemistry - Category: Chemistry Source Type: research