A photo-responsive electrocatalyst: CdSe quantum dot sensitized WS2 nanosheets for hydrogen evolution in neutral solution†
Abstract
Combining photochemical and electrochemical energy conversion into a single catalytic system is an efficient method for energy generation. In this paper, to increase the electrocatalytic activity of 2H-WS2 nanosheets, CdSe quantum dots (QDs) are introduced as sensitizers to design a novel photo-responsive electrode. The electrocatalytic HER activity of the nanocomposites is observably enhanced under 300 W Xe lamp irradiation (λ ≥ 420 nm, the overpotential decreases from −1030 mV vs. RHE to −400 mV vs. RHE at a cathodic current density of 10 mA cm−2 in neutral electrolyte without adding any sacrificial agent, and the Tafel slope decreases from 132 mV dec−1 to 56 mV dec−1). Moreover, the photo-enhanced electrocatalyst demonstrates high stability, which is reflected by a steady-state performance for more than 24 h. This strategy may have potential use in designing and fabricating novel photo-assisted electrocatalysts.