fig4

Figure 4. A: Schematic of the device for the photo-coupled electrocatalytic synthesis of H₂O₂. B: H₂O₂ production of photocatalysis, electrocatalysis and photo-coupled electrocatalytic systems. C: H₂O₂ production of OCN-x/CNTs (x = 100, 200, 300 or 400). D: Effect of bias voltage on H₂O₂ production. E: Decomposition capacity of H₂O₂ in different catalyst samples. F: Effect of different pH on H₂O₂ production; G: Long-time photocurrent of H₂O₂ production of the electrode. All the H₂O₂ production experiments were under the conditions of pH = 3, V = -0.5 V vs. SCE and λ ≥ 400 nm.