The present study investigated the electrochemical degradation of perfluorooctanoic acid (PFOA) by macroporous titanium suboxide (p-TiSO) anode in the presence of sulfate at pH-neutral condition (pH 6.9 +/- 0.3). Based on initial PFOA concentration of 0.1 mmol L-1, current density of 10 mA cm(-2) and electrolysis of 2 h, the removal efficiencies of PFOA were 97.1% and 90.8% for Na2SO4 electrolyte (k(app) = 2.1 h(-1)) and NaNO3 electrolyte (k= 0.84 h(-1)), corresponding to defluorination efficiency of 61.4% and 54.2%, respectively. The 2.3-fold enhancement of oxidation rate should be originated from the production of sulfate radicals (SO4 center dot-) by activation of sulfate via direct electron transfer with anode and indirect % OH-mediated oxidation under the potential of 3.01-3.41 V versus standard hydrogen electrode (SHE). The production of % OH and SO4 center dot- could be verified on a qualitative basis by using electron spin resonance (ESR) technology. Localized pH measurement achieved with a Pt/IrOx ultra-micro electrode revealed significantly lower pH inside the pores of p-TiSO anode (pH 2.6) compared to that in bulk electrolyte (pH 6.1). The formation of pH gradient should be attributed to surface interaction and diffusion restriction in the porous structure, and the resulting low pH was favorable for enhancing oxidizability of center dot OH toward activation of bisulfate and oxidation of PFOA pollutant. This study offers a proof-in-concept demonstration of electrochemical activation of sulfate and PFOA degradation without need for chemical addition and pH adjustment, which can be realized by simply creating macro-porous structure of anode materials in electrochemical advanced oxidation process.