Critical Role of Interface Design in Acceleration of Overall Water Splitting and Hybrid Electrolysis Process: State of the Art and Perspectives

Abstract

Electrocatalytic water splitting to hydrogen (H2) is an ideal approach to generate renewable energy. One of the major drawbacks is the tightly coupled kinetically sluggish and energy inefficient anodic oxygen evolution reaction (OER) with hydrogen forming a cathodic half-cell reaction which leads to a significant reduction in overall cell efficiency. In this context, before reviewing the literature, we have first briefly analyzed the energetics of overall water splitting, problems, and challenges under different pH conditions which can be useful for the further understanding of the process. Replacement of the anodic OER by a thermodynamically favorable substrate oxidation offers flexibility, value addition, and energy efficiency in the case of hybrid or assisted water electrolysis to afford hydrogen. Recent progress in terms of sacrificial oxidants in hybrid water electrolysis are discussed in this context, where the sacrificial oxidants are so chosen that the oxidation often leads to its value addition. Also here, we have offered insights into interface designing in heterostructures by modulating chemical and electronic environments for the enhancement of the intrinsic catalytic activity and stability. The effect of incorporation of such materials into the overall water splitting reaction, their catalytic active sites, and interactions with intermediates are thoroughly explored. This review can be a good complement for better understanding of the elucidation of the interface role in hybrid water electrolysis for future commercial applications.

Selective Facet Engineering of Ni12P5 Nanoparticle for Maximization of Electrocatalytic Oxidative Reaction of Biomass Chemicals

“…On the other hand, a large number of commodity chemicals which were originally produced via thermocatalysis under harsh conditions could be derived electrochemically under much milder conditions from biomass-derived platform chemicals. So, substitution of OER process by biomass-derived molecules for oxidation or substrate oxidation reaction − could be a lucrative way to get H 2 at a much lower potential budget than the conventional one. Biomass-derived chemicals like bioalcohols [methanol, ethanol, glycerol, butanol, 5-hydroxymethylfurfural (HMF) etc.]…”

Design Strategies of Active and Stable Oxygen Evolution Catalysts for Proton Exchange Membrane Water Electrolysis

“…Hydrogen production via water electrolysis can be performed under neutral, alkaline, and acidic environments. − Although neutral and alkaline water electrolyzers have their own advantages, they encounter critical challenges including sluggish kinetics of ionic conduction and CO 2 contamination . In contrast, acidic water electrolyzers, specifically proton exchange membrane water electrolyzers (PEMWEs), offer a distinct advantage of higher ionic conductivity of hydronium ions (350 S cm 2 mol –1 ), compared with that of hydroxide ions (198 S cm 2 mol –1 ) under alkaline conditions. , This high ionic conductivity improves the reaction kinetics of electrodes and the overall system performance of a PEMWE, leading to a high achievable current density of over 2 A cm –2 .…”

A Review of Nanostructured Transition Metal Phosphide-Driven Electrocatalytic Oxygen Evolution Reaction

“…Metal oxides based on earth-abundant first-row transition elements are explored as alternative oxygen evolution catalysts (OECs) in place of traditional electrocatalysts composed of precious-metal oxides (RuO 2 and IrO 2 ) . Here, high-pitched catalytic activity and significantly long durability of these OECs under a range of operating conditions have been the main focus for enabling broader adoption of energy storage via water splitting. , …”