Year: 2019
Type: article
Abstract: An improved understanding of the origin of the electrocatalytic activity is of importance to the rational design of highly efficient electrocatalysts for the hydrogen evolution reaction. Here, an ambipolar single‐crystal tungsten diselenide (WSe2) semiconductor is employed as a model system where the conductance and carrier of WSe2 can be individually tuned by external electric fields. The field‐tuned electrochemical microcell is fabricated based on the single‐crystal WSe2 and the catalytic activity of the WSe2 microcell is measured versus the external electric field. Results show that WSe2 with electrons serving as the dominant carrier yields much higher activity than WSe2 with holes serving as the dominant carrier even both systems exhibit similar conductance. The catalytic activity enhancement can be characterized by the Tafel slope decrease from 138 to 104 mV per decade, while the electron area concentration increases from 0.64 × 1012 to 1.72 × 1012 cm−2. To further understand the underlying mechanism, the Gibbs free energy and charge distribution for adsorbed hydrogen on WSe2 versus the area charge concentration is systematically computed, which is in line with experiments. This comprehensive study not only sheds light on the mechanism underlying the electrocatalysis processes, but also offers a strategy to achieve higher electrocatalytic activity.
Source: Advanced Science
Institutions: Aarhus University, Sichuan University, University of Nebraska–Lincoln, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Shandong University, University of Electronic Science and Technology of China, State Key Laboratory of Electronic Thin Films and Integrated Devices
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,000
Awards: G3429598991, G7341953730
OpenAlex ID: W2993898934