Enhancement of the chlor-alkali process via blue light irradiation using a WO3 photoelectrocatalyst

The chloralkaline industry is recognized for its technological maturity and high energy efficiency; however, recent advances seek to further optimize the process by integrating complementary technologies. In this work, a photoelectrochemical approach is explored as an alternative to conventional electrolysis to evaluate the impact of light irradiation on the generation of oxidized chlorine species (OCS) and hydrogen (H 2 ). A flow photoelectrolyzer equipped with a WO 3 anode, stainless steel cathode, and proton exchange membrane was designed, fabricated, and tested under different high-power LED irradiation conditions. The influence of current density and irradiation power on the formation of the products and the faradaic and energy efficiencies was systematically evaluated. Under optimal conditions (1.33 mA cm -2 , 10 W LED), the photoelectrolyzer achieved faradaic efficiencies of 38% for OCS and 71.8% for H 2 , with a notable reduction in cell voltage compared to the electrolyzer. Although the energy efficiency associated with simulated irradiation represents a challenge, the results indicate that in the presence of irradiation, higher rates and faradaic efficiencies are obtained for OCS and H 2 . Furthermore, mechanistic studies revealed that both h + and • OH radicals are essential for OCS formation. These findings reinforce the potential of photoelectrocatalysis as a viable route for sustainable chlor-alkali process enhancement and provide valuable insights into the coupling of photonic and electrochemical processes. • A photoelectrolyzer using a WO 3 anode was designed and successfully tested in the chloralkali process under LED irradiation. • Simultaneous generation of OCS and H 2 in the photoelectrolyzer resulted in high Faradaic efficiencies (38% and 71.8%). • Irradiation with a high-power 10 W LED reduces the cell voltage and improves the cogeneration performance. • Light irradiation enhances production; however, the use of artificial light limits the energy efficiency of the process. • This work proposes a mechanism for the formation of OCS via h + and • OH radicals in WO 3 .