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

Hydrogen peroxide (H 2 O 2 ) synthesis by electrochemical two-electron oxygen reduction has garnered increasing interest as an attractive alternative to the industrial anthraquinone process. However, the electrochemical H 2 O 2 synthesis suffers a low current efficiency due to O 2 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 O 2 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 O 2 under water, in sharp contrast to the difficult O 2 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 g cat –1 h –1 H 2 O 2 production rate (at 100 mA cm –2 ), which makes it possible to manufacture high-concentration H 2 O 2 (0.66–5.38 wt %). The high hydrophobicity feature of the three-phase NPC architecture endows the flood-proof ability that guarantees unblocked O 2 transport and trapping, thus enabling the durability for 200 h electrocatalytic H 2 O 2 synthesis at 100 mA cm –2 that largely outperforms its hydrophilic NPC counterparts. This H 2 O 2 electrosynthesis technology presents attractive potential in practical application, as demonstrated by the less expensive IrO 2 /Ti mesh anode construction, low electricity demand (0.15–0.43 kWh per kg 3 wt % H 2 O 2 ), and facile scale-up of device. This work presents a highly selective, durable, and low-cost H 2 O 2 electrosynthesis, providing a promising approach for the in situ H 2 O 2 production and utilization.