The Underlying Molecular Mechanism of Fence Engineering to Break the Activity–Stability Trade‐Off in Catalysts for the Hydrogen Evolution Reaction

Abstract

Non‐precious‐metal (NPM) catalysts often face the formidable challenge of a trade‐off between long‐term stability and high activity, which has not yet been widely addressed. Herein we propose a distinct molecule‐selective fence as a promising concept to solve this activity‐stability trade‐off. The fence encloses the catalyst and prevents species poisonous to the catalyst from reaching it, but allows catalytic reaction‐related species to diffuse freely. We constructed a CoS2 fence layer on the external surface of highly active cobalt‐doped MoS2, achieving a remarkable catalytic stability towards the alkaline hydrogen evolution reaction and improved activity. In situ spectroscopy uncovered the underlying molecular mechanism of the CoS2 fence for breaking the activity‐stability trade‐off of the MoS2 catalyst. This work offers valuable guidance for rationally designing efficient and stable NPM catalysts.

Electronic Modulation of Metal–Organic Frameworks by Interfacial Bridging for Efficient pH‐Universal Hydrogen Evolution

“…The valence state of Co atoms in CoBDC/ MXene is further estimated by the first derivative curves and the fitted average oxidation states from the Co K-edge XANES. [50] As shown in Figure 2e, the oxidation state of Co in the CoBDC/MXene (1.68) composite is between Co foil and CoO and higher than that of CoBDC (1.49) (Figure 2f), which is consistent with their XANES results. The elevated valence state of Co sites is caused by Co-O-Ti bridging at the heterostructure interface, which can accelerate charge/ion transfer during HER and enhance the intrinsic activity of the electrocatalyst.…”

Boosting the Stability of Oxygen Vacancies in α‐Co(OH)2 Nanosheets with Coordination Polyhedrons as Rivets for High‐Performance Alkaline Hydrogen Evolution Electrocatalyst

“…For instance, introducing a molecules‐elective fence of CoS 2 layer can protect Co‐MoS 2 from the corrosion of O 2 and OH − poisonous species in the electrical double layer, and thus effectively suppress the leaching of MoS 2 into the electrolyte, realizing a steady alkaline HER activity. [ 20 ] Additionally, modulating the components of the electrolyte, for example by using a V 5+ ‐saturated electrolyte, can significantly inhibit the photooxidation‐coupled dissolution of BiVO 4 . [ 21 ] Similarly, the addition of [Fe(CN) 6 ] 3− to 1.0 m KOH can result in a self‐healing process to slow down the etching process of the np + ‐Si photoanode and substantially extend the lifetime.…”

Atomic‐Level Design of Active Site on Two‐Dimensional MoS2 toward Efficient Hydrogen Evolution: Experiment, Theory, and Artificial Intelligence Modelling

“…For illustration, Cao's group reported a high‐efficient CoS 2 molecule fence that significantly improves the Co‐doped MoS 2 by inhibiting the oxidization and dissolution of MoS 2 under alkaline HER conditions, and the surface reconstruction of catalyst induced by O 2 and OH – . [ 243 ] DFT calculation results demonstrate the low binding energy of CoS 2 toward O 2 , high adsorption energy toward OH – and low water adsorption energies, which enables CoS 2 a high affinity towards H 2 O and repelling effect on O 2 and OH – . In the stability test, the polarization curves of Co‐MoS 2 @CoS 2 display no obvious change after 5000 CV cycles while the same test conditions lead to a polarization enhancement for Co‐MoS 2 .…”