Recent Advances in the Comprehension and Regulation of Lattice Oxygen Oxidation Mechanism in Oxygen Evolution Reaction

Water electrolysis,a process for producing green hydrogen from renewable energy,plays a crucial role in the transition toward a sustainable energy landscape and the realization of the hydrogen economy.Oxygen evolution reaction(OER)is a critical step in water electrolysis and is often limited by its slow kinetics.Two main mechanisms,namely the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),are commonly considered in the context of OER.However,designing efficient catalysts based on either the AEM or the LOM remains a topic of debate,and there is no consensus on whether activity and stability are directly related to a certain mechanism.Considering the above,we discuss the characteristics,advantages,and disadvantages of AEM and LOM.Additionally,we provide insights on leveraging the LOM to develop highly active and stable OER catalysts in future.For instance,it is essential to accurately differentiate between reversible and irreversible lattice oxygen redox reactions to elucidate the LOM.Furthermore,we discuss strategies for effectively activating lattice oxygen to achieve controllable steady-state exchange between lattice oxygen and an electrolyte(OH^(-)or H_(2)O).Additionally,we discuss the use of in situ characterization techniques and theoretical calculations as promising avenues for further elucidating the LOM.

Antagonism effect of residual S triggers the dual-path mechanism for water oxidation

Transition metal chalcogenides(TMCs)are recognized as pre-catalysts,and their(oxy)hydroxides derived from electrochemical reconstruction are the active species in the water oxidation.However,understanding the role of the residual chalcogen in the reconstructed layer is lacking in detail,and the corresponding catalytic mechanism remains controversial.Here,taking Cu_(1-x)Co_(x)S as a platform,we explore the regulating effect and existence form of the residual S doped into the reconstructive layer for oxygen evolution reaction(OER),where a dual-path OER mechanism is proposed.First-principles calculations and operando~(18)O isotopic labeling experiments jointly reveal that the residual S in the reconstructive layer of Cu_(1-x)Co_(x)S can wisely balance the adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM)by activating lattice oxygen and optimizing the adsorption/desorption behaviors at metal active sites,rather than change the reaction mechanism from AEM to LOM.Following such a dual-path OER mechanism,Cu_(0.4)Co_(0.6)S-derived Cu_(0.4)Co_(0.6)OSH not only overcomes the restriction of linear scaling relationship in AEM,but also avoids the structural collapse caused by lattice oxygen migration in LOM,so as to greatly reduce the OER potential and improved stability.

Upcycling electroplating sludge into bioengineering-enabled highly stable dual-site Fe-Ni_(2)P@C electrocatalysts for efficient oxygen evolution

The advancement of bimetallic catalysts holds significant promise for the innovation of oxygen evolution reaction(OER)catalysts.Drawing from adsorbate evolution mechanism(AEM)and lattice oxygen oxidation mechanism(LOM),the incorporation of dual active sites has the potential to foster novel OER pathways,such as the coupled oxygen evolution mechanism(COM),which can surpass the limitations of OER and elevate catalytic performance.In this study,uniformly distributed Fe/Ni dual-site Fe-Ni_(2)P@C electrocatalysts are crafted by upcycling metals in electroplating sludge via an eco-friendly and sustainable microbial engineering technique.Our findings indicate that a substantial number of defects emerge at the Ni2P crystal during the OER process,laying the groundwork for lattice oxygen involvement.Moreover,the displacement of Ni/Fe in the crystal lattice intensifies the asymmetry of the electronic structure at the metal active sites,facilitating the deprotonation process.This research introduces an innovative paradigm for the synthesis of effective and robust transition metal-based OER catalysts,with implications for sustainable energy generation technologies.

Accelerating Deprotonation Kinetics of RuO_(2)for Efficient Acidic Water Oxidation

The development of a highly efficient noniridium-based oxygen evolution reaction catalyst is the key to realizing large-scale commercial application of the proton-exchange membrane water electrolyzer.RuO_(2)is the most promising alternative to IrO_(2),but if usually suffers from lattice-oxygenmediated corrosion and sluggish proton transfer kinetics under acidic media.Herein,we propose an effective strategy of embedding RuO_(2)nanoparticles into a N-doped carbon support,termed as RuO_(2)-NC,to simultaneously prevent Ru dissolution and accelerate the bridging-oxygen-assisted deprotonation process.The obtained RuO_(2)-NC electrocatalyst presents high activity with an overpotential of 159 mV to reach 10 mA cm^(−2) and remarkable stability for over 240 h.Structural investigation and theoretical calculations reveal that the electron-rich NC substrate,as an electron donor,provides a buffered charge compensation to protect RuO_(2)from excessive oxidation and lattice oxygen loss by switching into a conventional adsorbate evolution mechanism(AEM).More importantly,the activated bridging oxygen(Obri)sites can facilitate the deprotonation of*OOH intermediates,leading to an optimized bridging-oxygen-assisted deprotonation AEM pathway.