High mineralization efficiency and low energy consumption are the core requirements for the application of electrochemical advanced oxidation processes (EAOPs) for organic pollutants degradation. Herein we reported innovative EAOPs using natural air diffusion electrode (NADE) to improve H₂O₂ production and enhanced utilization efficiency by combination with electro-Fenton and photoelectro-Fenton (EF-PEF) for the degradation of 2,4-dichlorophenoxyacetic acid. At 0.2 and 1.2 A, the H₂O₂ production on NADE possessed 158% and 188% of that on normal aeration electrode (AE) with the total energy consumption only 7.2% and 25.4% of that on AE, respectively. Such excellent H₂O₂ production performance on NADE was attributed to ultra-high oxygen mass transfer efficiency and the feature of not requiring aeration, which reduced energy consumption greatly. A new H₂O₂ utilization efficiency (HUE) evaluation index including decomposition ratio, conversion efficiency and total utilization efficiency of H₂O₂ were proposed, demonstrating that PEF had a higher HUE than EF but not cost-effective due to a higher energy consumption. EF-PEF was thus proposed to upgrade the traditional PEF, which reduced energy consumption while maintained high mineralization efficiency. The HUE in EF-PEF process was greatly improved and superior to most reported EAOPs in literatures, which explained the high mineralization efficiency (78%-87%) with an extremely low energy consumption (0.065-0.167 kWh (g TOC)^-1) even an order of magnitude lower than that in the literatures. This work enlightened the importance of two strategies of improving both H₂O₂ production and utilization efficiency to maintain high mineralization efficiency in H₂O₂ based EAOPs.