Sedimentation field flow fractionation and flow field flow fractionation as tools for studying the aging effects of WO3 colloids for photoelectrochemical uses

摘要: Abstract WO3 colloidal suspensions obtained through a simple sol–gel procedure were subjected to controlled temperature aging process whose time evolution in terms of particle mass and size distribution was followed by sedimentation field flow fractionation (SdFFF) (FlFFF). The experiments performed at 60 °C showed that few hours the initially transparent sol particles, less than 25 nm, undergoes progressive increase allowing nanoparticles reach maximum equivalent spherical about 130 nm after 5 h. observed shift maxima (SdFFF), broadening curves (FlFFF) SEM–TEM observations suggest mixed mechanism growth-aggregation initial nanocrystals form larger particles. photoelectrochemical properties thin films from aged regular intervals, tested biased photoelectrocatalytic cell with 1 M H2SO4 under solar simulated irradiation. current–voltage polarization recorded potential range 0–1.8 V (vs. SCE) diminution photocurrent 3.7 mA cm−2 2.8 mA cm−2 times 1 h 5 h, respectively. This loss performance mainly attributed reduction electroactive surface area sintered particles as suggested satisfactory linear correlation between integrated cyclic voltammetry cathodic wave W(VI) → W(V) measured dark.