Underpotential-deposition synthesis and in-line electrochemical analysis of single-atom copper electrocatalysts

Carbon supported single-atom catalysts (SACs) with well-defined active sites and maximum atom utilization efficiency exhibit good activity and selectivity toward a series of electrocatalytic reactions. For the practical applications of SACs, development of facile synthetic methods and analytical techniques is highly useful. Here, single-atom copper has been successfully anchored on sulfur sites of doped graphite foam via an underpotential deposition strategy. By this strategy, the loading amount of Cu SACs can be regulated through tuning the deposition potential, the S contents of the doped graphite foam and the concentration of Cu precursor; moreover, the regulation is perfectly in line with Nernst equation combined with Langmuir adsorption model. Importantly, a stripping voltammetry method is successfully developed for the first time to in-line quantitatively analyze the resultant Cu SACs. Our Cu SACs exhibit remarkable oxygen reduction reaction (ORR) activity with a half-wave potential of 0.862 V (vs RHE) and long-term stability.