Wireless pulsed nanophotoelectrochemical cell for the ultrafast degradation of organic pollutants

Abstract

An urgent demand exists for advanced-technologies to efficiently remove persistent organic pollutants from water, while minimizing energy consumption. Here, we introduce an innovative wireless nanophotoelectrochemical (nPEC) cell using pulsed light for the ultrafast degradation/mineralization of organic pollutants. The nPEC cell comprises a nanostructured Si-pn photodiode that monolithically integrates: (i) a Si-n/Au nanowire-based-photocathode for effective light absorption and photovoltage generation, and (ii) a Si-p/mesoporous-NiPt photoanode serving as catalyst to wirelessly amplify the sulfate radical production by low-intensity light without any bias voltage. The efficacy of the nPEC cell was shown by ultrafast degradation (>99 %) and mineralization (>98 %) of three emerging pollutants (tetracycline, levofloxacin and anatoxin-A). Notably, reaction kinetics were boosted by more than one order of magnitude when exposed to light intensities ca. 5-fold lower than sunlight. Remarkably, pulsed light beams in the 100–500 Hz range provided an additional enhancement in the degradation/mineralization efficiencies, reducing energy-input by half, while enhancing the catalyst's oxidation state and durability.