A composite acetylene black-PTFE cathode consisting of a sheet active core and a dampproof coating that mainly set up a hydrophile-hydrophobe balance on the cathode surface has been fabricated. The H2O2 was electrogenerated and the main factors affecting the H2O2 yield of the cathode were investigated using a three-electrode undivided cell fed with air as O-2 source in Na2SO4 solution of 0.05 M. The experimental results showed that: (1) at the hydrophile-hydrophobe balance, the cathode could utilize not only O-2 dissolved in the electrolyte but also O-2 in air bubbles as O-2 source for the electrogeneration of H2O2, which improved the O-2 utilization and, as a result, increased the H2O2 yield; (2) the composite cathode with an optimal working current density of 108 mA cm(-2) had a much higher current carrying capacity than the cathode without coating with an optimal working current density of 24 mA cm-2; (3) at the optimal current density of 108 mA cm(-2) and pH 3 through 2.5 hour of electrolysis, the accumulation of H2O2 reached 677.5 mg L-1 with a H2O2 production rate of 54.2 mg cm-2 h(-1) that was the maximum reported so far, a current efficiency of 79.1% and energy consumption of 27.5 kWh kg(-1); (4) the cathode could electrogenerated H2O2 highly effectively until the cathode potential reached-3.9 V vs. SCE; (5) the dampproof coating could inhibit effectively the electrowetting of the cathode surface, and, as a result, increased greatly the useful life of the composite cathode. (C) 2014 Elsevier Ltd. All rights reserved.