Hydrogen evolution reaction on single crystal WO_3/C nanoparticles supported on carbon in acid and alkaline solution

摘要

Single crystal tungsten oxide (WO_3) nanoparticles were prepared via a microwave-assisted method. Electrochemical activity for hydrogen evolution reaction (HER) on WO_3 supported on carbon black (WO_3/C) electrocatalyst was first studied in acid solution (0.5 M H_2SO_4) and alkaline solution (1.0 M KOH) at room temperature. The overall experimental results revealed that the electrocatalytic activity for HER on WO3/C is one order magnitude higher than those obtained with carbon black in 0.5 M H-2SO_4 and is six times than in the case of carbon black in 1.0 M KOH. These results demonstrated that WO_3 could enhance the electrocatalytic activity for hydrogen evolution reaction in acid solution (0.5 M H_2SO_4) and alkaline solution (1.0 M KOH). On the other hand, the kinetic reaction mechanisms were discussed on WO3/C electrocatalysts and carbon black in acid solution and alkaline solution for HER. Consequently, the rate-determining step changed from Tafel to Volmer due to the incorporation of WO_3 in acid solution. However, the rate-determining step carries through Tafel reaction on both electrocatalysts in alkaline solution though WO_3 was introduced.