Durable and Selective Electrochemical H2O2 Synthesis under a Large Current Enabled by the Cathode with Highly Hydrophobic Three-Phase Architecture

Hydrogen peroxide (H2O2) synthesis by electrochemical two-electron oxygen reduction has garnered increasing interest as an attractive alternative to the industrial anthraquinone process. However, the electrochemical H2O2 synthesis suffers a low current efficiency due to O2 diffusion restriction when performing at a large current, which would be further aggravated by the electrode flooding issue. Here, we present a highly hydrophobic gas–liquid–solid three-phase architecture consisting of densely distributed N-doped carbon (NPC) nanopolyhedra, which presents the superaerophilicity feature to achieve rapid gaseous O2 transport and trap even under high-current operation by virtue of electrolyte-flooding resistibility. The aerophilicity of the hydrophobic NPC architecture is visibly verified by the rapid trapping for gaseous O2 under water, in sharp contrast to the difficult O2 capture by the hydrophilic NPC surface. Using the aerophilic three-phase NPC architecture, it can deliver a current of 50–250 mA cm–2 with an 83–99% current efficiency, achieving an 8.53 mol gcat–1 h–1 H2O2 production rate (at 100 mA cm–2), which makes it possible to manufacture high-concentration H2O2 (0.66–5.38 wt %). The high hydrophobicity feature of the three-phase NPC architecture endows the flood-proof ability that guarantees unblocked O2 transport and trapping, thus enabling the durability for 200 h electrocatalytic H2O2 synthesis at 100 mA cm–2 that largely outperforms its hydrophilic NPC counterparts. This H2O2 electrosynthesis technology presents attractive potential in practical application, as demonstrated by the less expensive IrO2/Ti mesh anode construction, low electricity demand (0.15–0.43 kWh per kg 3 wt % H2O2), and facile scale-up of device. This work presents a highly selective, durable, and low-cost H2O2 electrosynthesis, providing a promising approach for the in situ H2O2 production and utilization.