Unlocking the Potential of Mechanochemical Coupling: Boosting the Oxygen Evolution Reaction by Mating Proton Acceptors with Electron Donors

Abstract

The oxygen evolution reaction (OER) is the bottleneck of many sustainable energy conversion systems, including water splitting technologies. The kinetics of the OER is generally sluggish unless precious metal‐based catalysts are used. Perovskite oxides have shown promise as alternatives to these expensive materials. However, for several perovskites, including SrCoO3−δ, the rate‐limiting step is proton‐transfer. In this study, it is shown that such a kinetic limitation can be overcome by coupling those perovskites with MoS2 mechanochemically. By studying composites of SrMO3−δ (M = Co, Fe, Ti) and MoS2, the role that the formed heterointerfaces play in enhancing the activity is investigated. Mechanochemically mating SrCoO3−δ and MoS2 increases the mass activity toward OER by a factor of ten and led to a Tafel slope of only 37 mV dec−1. In contrast, combining MoS2 with SrFeO3−δ or SrTiO3−δ, two materials whose OER is not limited by proton‐transfer, does not result in an improvement of the performance. The experimental measurements and first‐principle calculations reveal that the MoS2 at the MoS2@SrCoO3−δ heterointerfaces is both an electron and a proton acceptor, thereby facilitating deprotonation of the perovskite and resulting in faster OER kinetics.

Single-Layer MoS2 Grown on Atomically Flat SrTiO3 Single Crystal for Enhanced Trionic Luminescence

“…Particularly for the compositional systems of TMDs and oxides, such phenomenon can provide an efficient strategy to control the charge carriers, the photovoltaic, the photoluminescence as well as the catalytic activities of the TMDs materials via tuning the electronic interactions from the oxide substrates. 32,51,52 On the basis of the charge transfer and band-bending picture as derived by KPFM and XPS, we would further determine band levels of both MoS 2 and SrTiO 3 relative to the aligned Fermi level, which usually plays a critical role in determining the potential applications of the hybridized semiconductors. To do this, we have applied ultraviolet photoelectron spectroscopy (UPS) measurements on both Nb:SrTiO 3 (111) and MoS 2 -Nb-SrTiO 3 (111) samples to examine their valence bands.…”

Solid-State Ball-Milling of Co3O4 Nano/Microspheres and Carbon Black Endorsed LaMnO3 Perovskite Catalyst for Bifunctional Oxygen Electrocatalysis

“…Furthermore, in recent years, hybridization of perovskite materials with other materials (e.g., MoS 2 ) has also been enhanced the water oxidation properties in both an acidic and alkaline environment. Indeed, a study indicates that the mechanochemical coupling via ball-milling process creates intimately connected heterointerfaces between the perovskite and MoS 2 that can synergistically boost the OER activity [26,27]. By all these studies, we predict that the incorporation of Co 3 O 4 nano/microspheres with carbon black supported LaMnO 3 perovskite catalyst can be a potential material to improve the conductivity, stability, and electrocatalytic activity in an alkaline media.…”

A tin‐incorporated multi‐phase perovskite nanocomposite for efficiently catalyzing oxygen evolution reaction

“…[32][33][34][35][36] Considering the difficulty in developing a single-phase perovskite oxide through B-site cation doping to fulfill all the requirements (such as adequate phase stability, high conductivity, and sufficient activity at room temperature) as an OER electrocatalyst, adopting composite electrodes, upon which different components contribute to different functionalities, is considered a superior alternative. [37][38][39][40] Generally, composite electrodes are fabricated by physical mixing of different phases or by impregnating extra phase into pre-integrated scaffold phase, where constituent phases are pre-synthesized before assembling the composite material. Unfortunately, these fabrication techniques necessitate additional steps and suffer from limited interface boundaries stemmed from mixing inhomogeneity and large grain size of the components, leading to high cost and poor activity for electrochemical reactions.…”

“…In order to tackle the challenge, the incorporation of stable high‐valence cations into B‐site is a beneficial method to improve the structural stability of SC perovskite at reduced temperatures due to their high electrostatic repulsion between B‐site cations 32‐36 . Considering the difficulty in developing a single‐phase perovskite oxide through B‐site cation doping to fulfill all the requirements (such as adequate phase stability, high conductivity, and sufficient activity at room temperature) as an OER electrocatalyst, adopting composite electrodes, upon which different components contribute to different functionalities, is considered a superior alternative 37‐40 . Generally, composite electrodes are fabricated by physical mixing of different phases or by impregnating extra phase into pre‐integrated scaffold phase, where constituent phases are pre‐synthesized before assembling the composite material.…”