The potential‐driven semiconductor‐to‐metal transition is investigated in monolayer transition metal dichalcogenides by employing a new proposed method, i.e., the fixed‐potential method (FPM). Under the same voltage, the semiconducting and metallic phases will be charged differently due to their different electronic properties. The potential‐driven phase transition process is simulated by the injection of unequal electrons in the semiconducting and metallic phases. The unequal electron injection is more consistent with the actual experimental process, although equal electron injection also can theoretically induce a phase transition. MoTe2 is chosen as a prototypical example to examine the physical mechanism. When the fixed electrode potential is above the potential of zero‐charge, excess electrons are injected into the metallic 1T’ phase instead of the semiconducting 2H phase, stabilizing the 1T’ phase. In addition, the potential‐dependent kinetics, in which the charge transfer is fluctuating, suggests that increasing the electrode potential will decrease the kinetic barrier of the 2H→1T’ transition process. The calculated relative transition voltage of 2.5 V agrees well with the experimental results, demonstrating the validity of the FPM. This study provides new insight into potential‐driven semiconductor‐to‐metal phase transitions and suggests a new theoretical approach for studies under constant voltage conditions.
A fundamental understanding of the catalytic mechanisms of the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) at applied electrode potentials is crucial for designing bifunctional catalysts. Here, we revisit the OER and ORR on single-atom catalysts (SACs) by using the grand canonical fixed-potential method. It is revealed that the charge states of reaction intermediates are linearly related to the potential through the capacitance and surface area, and different intermediates exhibit different charge states under the same potential, which arises from the adsorption-induced change in the work function and surface dipole. As a result, the charge transfer in each proton-coupled electron-transfer step is no longer 1e − , yielding a deviation of the potential-dependent relative free energy from the simple expression with a linear potential correction as in the conventional computational hydrogen electrode model, further affecting the evaluation of overpotential and catalytic activity. Importantly, the slopes of universal scaling relations decrease linearly with increasing electrode potential, resulting in distinct scaling relationships for the OER and ORR. These findings highlight the key role of the potential effects on the OER/ORR and update the understanding of the catalytic mechanisms and catalytic activity trends under working potential.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.