SO2 removal with a simultaneously improved solar-to-H2 energy conversion

Sulfur dioxide (SO2) emitted from fossil fuels burning and chemical industries can cause lots of harmful issues in the environment. In a conventional method for SO2 removal, aqueous sodium hydroxide (NaOH) solution is... [ view full abstract ]

Sulfur dioxide (SO2) emitted from fossil fuels burning and chemical industries can cause lots of harmful issues in the environment. In a conventional method for SO2 removal, aqueous sodium hydroxide (NaOH) solution is typically utilized to absorb SO2 from flue gas. The resulted Na2SO3 solution is then purged with air for an oxidation of Na2SO3 before disposal. The energy of Na2SO3 is wasted in this process. Herein, we propose that the solar-to-H2 energy conversion efficiency can be greatly improved with a simultaneous removal of venenous SO2 via a photoelectrochemical water splitting process, since Na2SO3 possesses lower activation energy and faster kinetics as compared with the direct oxidation of water on the photoanode. A H2 production rate of 41 μmol h-1cm-2, with a Faradaic efficiency of 98%　is obtained in 0.075 M Na2SO3. This work provides a new method for the SO2 removal with a simultaneous H2 production.

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