High-efficient preparation and screening of electrocatalysts using a closed bipolar electrode array system

Abstract

High-efficient preparation and screening of electrocatalysts for oxygen reduction reaction (ORR) was realized by a three electrode driving closed bipolar electrode (BPE) array system. As high concentrations of Fe(CN)63−/4− (both 200 mM) existed in the anodic cell of the BPE system and same electrode material was adopted by the BPE anodic pole and driving electrode in anodic cell, the anodic cell performed similar to “good conductor” and the electrochemical behavior of the closed BPE system approximately equal to that of the three-electrode system in cathodic cell. Based on the above property and the parallel array, electrocatalysts containing bimetallic Pt Au and reduced graphene oxide (PtAu-rGO) with varying metal proportion were successfully prepared on the cathodic BPE poles by a two-step reduction process. Graphene oxide was firstly reduced to reduced graphene oxide (rGO) in each cathodic pole by cyclic voltammetry, and then Pt Au with different metal proportion were electrodeposited on the surface of rGO. Afterward, in-situ and high-throughput screening of these electrocatalysts for ORR was carried out based on the electrochemiluminescence (ECL) imaging on the corresponding anodic BPE poles. The screening results were consistent with those of the conventional electrochemical method by testing the catalytic performance one by one very well. This closed BPE array system with one potentiostat not only can prepare multiple catalyst candidates at the same time, but also can evaluate them, simultaneously, which is of great immediate significance to the field of fuel cell.