Half-reaction Of Water Splitting Research Articles

Bifunctional Electrocatalysts for Overall and Hybrid Water Splitting.

Electrocatalytic water splitting driven by renewable electricity has been recognized as a promising approach for green hydrogen production. Different from conventional strategies in developing electrocatalysts for the two half-reactions of water splitting (e.g., the hydrogen and oxygen evolution reactions, HER and OER) separately, there has been a growing interest in designing and developing bifunctional electrocatalysts, which are able to catalyze both the HER and OER. In addition, considering the high overpotentials required for OER while limited value of the produced oxygen, there is another rapidly growing interest in exploring alternative oxidation reactions to replace OER for hybrid water splitting toward energy-efficient hydrogen generation. This Review begins with an introduction on the fundamental aspects of water splitting, followed by a thorough discussion on various physicochemical characterization techniques that are frequently employed in probing the active sites, with an emphasis on the reconstruction of bifunctional electrocatalysts during redox electrolysis. The design, synthesis, and performance of diverse bifunctional electrocatalysts based on noble metals, nonprecious metals, and metal-free nanocarbons, for overall water splitting in acidic and alkaline electrolytes, are thoroughly summarized and compared. Next, their application toward hybrid water splitting is also presented, wherein the alternative anodic reactions include sacrificing agents oxidation, pollutants oxidative degradation, and organics oxidative upgrading. Finally, a concise statement on the current challenges and future opportunities of bifunctional electrocatalysts for both overall and hybrid water splitting is presented in the hope of guiding future endeavors in the quest for energy-efficient and sustainable green hydrogen production.

Soluble Gd6Cu24 clusters: effective molecular electrocatalysts for water oxidation.

The water oxidation half reaction in water splitting for hydrogen production is extremely rate-limiting. This study reports the synthesis of two heterometallic clusters (Gd6Cu24-IM and Gd6Cu24-AC) for application as efficient water oxidation catalysts. Interestingly, the maximum turnover frequency of Gd6Cu24-IM in an NaAc solution of a weak acid (pH 6) was 319 s-1. The trimetallic catalytic site, H2O-GdIIICuII2-H2O, underwent two consecutive two-electron two-proton coupled transfer processes to form high-valent GdIII-O-O-CuIII2 intermediates. Furthermore, the O-O bond was formed via intramolecular interactions between the CuIII and GdIII centers. The results of this study revealed that synergistic catalytic water oxidation between polymetallic sites can be an effective strategy for regulating O-O bond formation.

NiFe codoping-regulated amorphous/crystalline heterostructured Co-based hydroxides/tungstate with rich oxygen vacancies for efficient water oxidation catalysis

Oxygen evolution reaction (OER) is a crucial half-reaction in water splitting, generating hydrogen for sustainable development, but it is often subject to sluggish kinetics. Abundant transition metal-based OER electrocatalysts have been utilized to expedite the process. However, traditional amorphous catalysts suffer from low conductivity, while the activity of crystalline catalysts is also unsatisfactory. Herein, an amorphous/crystalline heterostructured Co-based hydroxide/tungstate was meticulously constructed and further tailored using a NiFe codoping method (NiFeCoW). Following NiFe codoping, the electronic structure had been modulated, subsequently altering the adsorption toward intermediates. From the electrochemical measurements, the NiFeCoW catalyst demonstrated superior electrocatalytic activity for OER in alkaline media, with a minimal overpotential of 297 mV at 10 mA cm−2 and a cell voltage of 1.57 V for water splitting. This study provides valuable guidance for regulating the amorphous/crystalline heterophase in catalysts through bimetallic modulating engineering.

(Invited) Decoupling Strategies in Electrochemical Water Splitting

The storage of renewably-generated energy as hydrogen via the electrolysis of water is a fundamental cornerstone of a sustainable hydrogen economy. Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Decoupled Electrolysis (see, for example: Nature Chem. 2013, 5, 403-409; Science, 2014, 345, 1326-1330; J. Am. Chem. Soc. 2016, 138, 6707–6710; Joule, 2018, 2, 1390-1395; Adv. Energy Mater. 2020, 2002453; Electrochim. Acta, 2020, 331, 135255) has the potential to overcome some of the challenges surrounding electrolysis using low and/or sporadic power inputs (especially those related to gas crossover) as the decoupling of the two half reactions of water splitting allows the oxygen and hydrogen evolution reactions to be performed at different times, in different places and at rates that are not linked to each other. In this talk, we shall give an overview of decoupled electrolysis using liquid redox mediators and also explore the use of decoupling agents in other contexts such as redox flow batteries (Nature Chem. 2018, 10, 1042-1047) and electrosynthesis (Chem. Commun. 2018, 54, 1093-1096). Figure 1

Co-Cl-C composited films prepared by flash Joule heating system as an efficient electrocatalyst for the oxygen and hydrogen evolution reaction

Co-based compound is a kind of bifunctional electrocatalyst for the half reactions of water splitting. Here we report the catalytic performance of Co-Cl-C composited catalyst prepared by flash Joule heating system in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It is found that Co-Cl-C composited film is an efficient electrocatalyst of OER and HER. In addition, the flash Joule heating is a fast, low energy consumption, and environmentally friendly preparation method. It opens up a new idea for the preparation method of composite materials.

Ni-MOF-based electrodes: A promising strategy for efficient overall water splitting

Hydrogen is a promising energy source to replace fossil fuels. Among the methods of generating hydrogen, electrochemical water splitting is distinguished by its ecologically friendly, high efficiency, sustainability, and ability to produce this element without the limitation of geological conditions and scaling devices. However, electrochemical water splitting is thermodynamically unfavorable, especially because its oxidation half-reaction (OER) and commercially available catalysts are expensive and not abundant in natural resources. The efficacy of commonly employed HER catalysts, such as Pt/C, is well-established. However, their high cost and limited natural resources present significant impediments. Given the slow kinetics of OER and the requisite catalyst demand for both HER and OER, it is paramount to pursue alternative solutions that are cost-effective, facile, and more widely accessible. Various new technologies and active materials have recently been developed in electrochemical water splitting for hydrogen production. There are still many knowledge gaps, including how preparation methods, chemical composition, and morphology of electrocatalysts affect both half-reactions of water splitting. Therefore, this work presents a smart approach to selectively activate NiMOF-based active materials in HER and OER. We demonstrate high-performance electrocatalysts based on Nickel/metal-organic frameworks (NiMOF) fabricated via two routes: A - drop cast on pristine Nickel foam with improved activity in OER (flower-like structure), B - Ni foam in situ impregnated by NiMOF during synthesis with improved activity in HER (rectangular-like structure). It allows the demonstration of highly efficient and robust electrocatalysts. Furthermore, in-situ studies on structural changes in the active materials have been conducted to reveal water-splitting half-reaction mechanisms.

Ce–Metal–Organic Framework-Derived CeO2–GO: An Efficient Electrocatalyst for Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is a crucial half-reaction in water splitting. However, this reaction is kinetically sluggish owing to the four-electron (4 e−) transfer process. Therefore, the development of low-cost, stable, highly efficient, and earth-abundant electrocatalysts for the OER is highly desirable. Metal oxides derived from metal–organic frameworks (MOFs) are among the most efficient electrocatalysts for the OER. Herein, Ce–MOF-derived CeO2/graphene oxide (GO) composites were successfully prepared using a facile method. The composites with 0, 25, 50, and 100 mg GO were named CeO2, CeO2–GO-1, CeO2–GO-2, and CeO2–GO-3, respectively. The physicochemical characteristics of the electrocatalysts were assessed using several analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis. The TEM results revealed that the CeO2 had a sheet-like morphology and that a GO layer was noticeable in the synthesized CeO2–GO-3 composite. The characterization results confirmed the formation of impurity-free CeO2–GO composites. The OER activity and stability were measured using cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The CeO2–GO-3 electrocatalyst has a smaller Tafel slope (176 mV·dec−1) and lower overpotential (240 mV) than the other electrocatalysts. In addition, it exhibited high cyclic stability for up to 10 h. Therefore, the inexpensive CeO2–GO-3 electrocatalyst is a promising OER candidate.

Peony-like CuxSy hybrid iron-nickel sulfide heterogeneous catalyst for boosting alkaline oxygen evolution reaction

Designing and fabricating earth-abundant and highly-efficient electrocatalysts is vital to accelerate dynamics of the oxygen evolution reaction (OER), which is a half reaction of water splitting. In the present work, we developed and successfully synthesized copper sulfides with diverse valence states hybridizing iron-nickel sulfide (CuxSy/FeNiS) heterogeneous catalyst via a governable two-step hydrothermal method, which processes superior OER performance and outstanding durableness in 1.0 M KOH solution. Benefitting from the polyvalent copper dopant and competent interfacial effects between Cu sulfides and FeNiS, this self-supported hybrid material requires 286 and 354 mV to achieve 50 and 500 mA cm−2, respectively. Besides, the plentiful disordered structures in CuxSy/FeNiS hybridization also enrich the exposure sites and modulate the electronic interaction of active sites and enhance the intrinsic OER activity. Furthermore, this optimal CuxSy/FeNiS electrode exhibits remarkable stability at both 10 and 100 mA cm−2 prolonged chronopotentiometry process.

Caterpillar-like 3D graphene nanoscrolls@CNTs hybrids decorated with Co-doped MoSe2 nanosheets for electrocatalytic hydrogen evolution

• The CNTs are CVD grown on the surface and inner space of graphene nanoscrolls to form unique caterpillar-like structure. • The caterpillar-like carbon materials as scaffold greatly improve the catalytic activity of active materials (MoSe 2 ). • The encapsulated Ni nanoparticles of unique caterpillar-like structure can optimize the electron structure of the outmost loading (MoSe 2 ) by electron traversing effect. • Electron traversing effect and doping effect can be synergistically applied in elevating catalytic performance. Hydrogen is a clean and flexible energy carrier that has the promising to satisfy urgent demands of the energy crisis and environmental protection. Electrochemical hydrogen evolution reaction (HER), a critical half-reaction in water splitting, is one of the greenest and most common methods to obtain high-purity hydrogen. Designing preeminent activity and stability electrocatalysts for hydrogen precipitation reaction (HER) to reduce energy consumption is of great essential. 3D carbon-based materials have attracted widespread concern as the potential scaffolds of highly active and durable electrocatalysts for HER. To boost the HER activity and prolong the lifespan of electrocatalysts, multifarious 3D carbon architectures make an appearance to be engineered for accelerating electronic/mass transfer and maximizing the exposure of active sites. Herein, we designed and fabricated high-performance electrocatalysts based on a special caterpillar-like 3D graphene nanoscrolls@CNTs (GNS@CNTs) scaffold decorated with Co-doped MoSe 2 nanosheets for HER. In the caterpillar-like hierarchical structure, CNTs were seamlessly co-bonded and dilated the interlayer and outer spacing of GNS through CVD growth technology, and nickel nanoparticles were covered by the CNTs tips. Taking advantage of the plentiful hierarchical pore, larger specific surface area, and higher chemical stability of the caterpillar-like structure, the catalysts exhibited enhanced electrocatalytic properties than some existing data reported. Density functional theory calculations showed that the encapsulated nickel nanoparticle could tune the electronic structure of the outer anchored Co-doped MoSe 2 and optimize its ∆ G of H* adsorption by electron traversing effect and doping effect. These indicate that caterpillar-like GNS@CNT is an ideal scaffold for anchoring actives substance and is suitable for high-efficient HER. This study provides new insights for designing hierarchical carbon composite nanostructures for catalysts, sensors, energy materials, and other applications.

Synthesis and study of electrochemical properties of Ni-Co-V@PrGO to enhance hydrogen evolution reaction

Hydrogen evolution reaction (HER) is kinetically slow as a necessary half-reaction in water-splitting. It requires high-efficiency electrocatalysts to reduce the overpotential and improve energy conversion efficiency. Transition-metal electrode materials with high stability and efficiency have become the frontiers of energy conversion and storage fields. The present work involves the investigation of transition metals as electrocatalysts for HER. On the other hand, various carbon nanomaterials, including carbon nanotubes, activated carbon, and graphene for high-performance electrocatalysts, have been successfully shown. Still, their performances must be improved (using phosphorus-doped graphene) for wider and more challenging applications. The Ni-Co-V@PrGO was synthesized through a simple method with an amorphous structure that enhanced catalytic activity toward hydrogen evolution reaction with a Tafel slope of 80 and 58 mV dec−1 (counter electrode: Pt) and 85 and 118 mV dec−1 (counter electrode: graphite) in alkaline and acidic media, respectively. Hereupon this research presents a simple and efficient high-performance electrocatalyst for HER.

Latest insights on eco-friendly metal based-electrocatalyst for oxygen evolution reaction: Challenges, and future perspectives

Oxygen evolution reaction (OER) is acknowledged as a significant half-reaction in water splitting for long-term hydrogen generation. In this context, developing effective catalysts for OER has thus far been the subject of considerable effort. Owing to their high activity and stability as inexpensive OER electrocatalysts, in addition to non-metals and oxide metals-based oxides considered the standard, metals have attracted a growing interest. The design and synthesis of all types of metal for water oxidation electrocatalysis are succinctly outlined in this review. Besides, some typical uses for these metals are noted. Moreover, the outlook and development trends are explored.

Plasmon coupling inside 2D-like TiB2 flakes for water splitting half reactions enhancement in acidic and alkaline conditions

Hybridization of catalytic and plasmon active materials provides an elegant way for efficiently improving of photo-electrochemical (PEC) water splitting. In this work, we propose the utilization of the plasmon coupling between surface plasmon polariton (SPP) and localized surface plasmon (LSP) for gigantic light concentration and triggering of the catalytic activity of titanium diboride (TiB2) flakes. The enhancement of TiB2 flakes' catalytic activity as a result of coupled plasmon triggering was investigated in PEC, including hydrogen and oxygen evolution half-reactions (HER and OER) performed in alkaline and acidic conditions. Additional studies performed at various light wavelengths and the time-dependent response of the structure show that the catalytic activity is triggered through the excitation of electron-hole pairs in TiB2 and their subsequent separation/acceleration in strong coupled plasmons field. In general, our work provides one of the first attempts how to realize a symmetric and less pH-sensitive catalyst for PEC water splitting.

Steering the construction of amorphous/crystalline hierarchical structure for accelerating the oxygen evolution reaction rate

As electrochemical water splitting is an extremely promising direction for solving future energy problems and the oxygen evolution reaction (OER) is the key half-reaction in water splitting, it is necessary to develop a new type of highly active and stable non-noble metal catalyst. Herein, we construct a series of hierarchical structure by modifying ZIF-67 on clustered-MnO2 nanotubes which are used as precursor. The fruit@branch-shaped compounds, marked as X@MnO2 (X = CoSx, Co3O4 and CoP). Compared with pure MnO2 nanotubes, the obtained derivatives imaginably result in the unique hierarchical structure and introduce synergistic effect between MnO2 and Co-based species that result in higher performance. In Particular, owing to the abundant active sites, a facil mass transfer pathway and improved electrical conductivity in amorphous/crystallize hierarchical structure, CoSx@MnO2 possesses the highest electrocatalytic activity with a lower overpotential of 329 mV at the current density of 10 mA cm−2, which is superior to most MnO2-based catalyst previously reported. Most importantly, to expand this strategy is an effective way to synthesize more high-activity catalysts.

Electrocatalytic activity of layered oxides SrLaAl1/2M1/2O4 (M = Mn, Fe, Co) for hydrogen- and oxygen-evolution reactions

A series of quasi-2D oxides, with formula SrLaAl1/2M1/2O4 (M = Mn, Fe, Co), have been synthesized and their electrocatalytic activity has been investigated for both half reactions of water splitting, namely oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). These layered oxides consist of octahedrally coordinated Al/M metals, where the octahedra are separated by alkaline earth/rare earth cations. Among the synthesized materials, SrLaAl1/2Co1/2O4 shows the best performance, evident from considerably lower overpotentials for OER and HER, as well as faster reaction kinetics, evaluated by the Tafel method. The improved performance of SrLaAl1/2Co1/2O4 is explained in terms of a combination of factors, including the greater bond covalency due to the higher electronegativity of Co than Mn and Fe, as well as the favorable electronic configuration of trivalent cobalt. Importantly, the electrical conductivity studies indicate a correlation between charge transport and the electrocatalytic activity, where the most active catalyst also shows the highest electrical conductivity.

Bimetallic Cobalt–Nickel Electrode Made by a Sputtering Technique for Electrocatalytic Hydrogen Evolution Reaction: Effect of Nickel Ratios

Electrocatalytic hydrogen evolution reaction (HER), a half-reaction of water splitting, is highly important to be developed for green and sustainable hydrogen production. In this work, a bimetallic cobalt–nickel (CoNix) alloy is deposited on nickel foam with a home-made target by using a radio frequency (RF) magnetron sputtering technique at a low deposition temperature. The as-sputtered CoNix was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy to evaluate its physical and chemical properties. The electrochemical measurement exhibited that the bimetallic CoNix alloy had a promising performance for HER in alkaline solutions. CoNi4, as the optimum ratio, possessed low overpotentials of 53 and 175 mV to achieve current densities of 10 and 100 mA/cm2, respectively. Moreover, among the as-sputtered CoNix, CoNi4 had the largest electrochemical surface-active area (485 cm2) and the lowest electron-transfer resistance (1.14 Ω). CoNi4 was also quite stable under the continuous operation of constant current densities of 10 and 50 mA/cm2 for 20 h. This work is based on the RF magnetron sputtering technique for developing bimetallic CoNix alloy as an efficient HER catalyst for electrochemical energy.

One-Step Synthesis of Highly Active NiFe Electrocatalysts for the Oxygen Evolution Reaction.

Electrochemical water splitting is a key technology for the conversion of renewable energy into chemical resources such as hydrogen. However, the oxygen evolution reaction (OER), a half-reaction of water splitting, is so slow that various effective catalysts for the OER have been explored. In this study, we demonstrate a simple and direct process for the synthesis of OER-active NiFe catalysts over electrodes. A NiFe/C catalyst layer was formed on a glassy carbon electrode by simply dropping the catalyst ink containing only metal nitrates and carbon black. The catalyst layer exhibited higher OER performance than the state-of-the-art Ir/C catalyst. The presence of carbon black is essential to enhance the OER activity of NiFe because carbon black helps to disperse the NiFe active sites. Cyclic voltammetry indicated that Ni and Fe are adjacent to each other on the surface of carbon black, resulting in significantly higher activity of NiFe/C compared to those of Ni/C and Fe/C. The effects of the Ni/Fe ratio, amount of carbon black, and type of carbon black on the OER activity of NiFe/C were examined in detail. Furthermore, we discuss the factors that determine the OER performance of NiFe/C.

One-dimensional cobalt oxide nanotubes with rich defect for oxygen evolution reaction

For the electrochemcial hydrogen production, the oxygen evolution reaction (OER) is a pivotal half-reaction in water splitting. However, OER suffers sluggish kinetics and high overpotential, leading to the increase of overall energy consumption and decrease of the energy efficiency. In this work, high-quality cobalt oxide porous nanotubes (Co3O4-PNTs) are easily obtained by simple self-template approach. One-dimensional (1D) porous structure provides the large specific surface area, enough abundant active atoms and effective mass transfer. In addition, Co3O4-PNTs also own self-stability of 1D architecture, benefitting the their durability for electrocatalytic reaction. Thus, Co3O4-PNTs with optimal annealing temperature and time reveal the attractive alkaline OER performance (Tafel slope of 56 mV dec−1 and 323 mV overpotential at 10 mA cm−2), which outperform the Co3O4 nanoparticles and benchmark commercial RuO2 nanoparticles. Furthermore, Co3O4-PNTs also exhibit excellent OER durability for least 10 h at the 10 mA cm−2. Overall, Co3O4-PNTs with low cost can be serve as a highly reactive and economical catalyst for OER.

Gadolinium doped CeO2 for efficient oxygen and hydrogen evolution reaction

Hydrogen evolution reaction (HER) is a significant half reaction in water splitting and it is spirit of energy storage and conversion applications. Recently, high durability and catalytic activity of effective electrodes are necessary to enlarge clean and sustainable energy sources. However, overcoming the overpotential and to improve HER and OER performance is still one of the complicated tasks. Hence, in this present work, gadolinium (Gd) doped cerium oxide (CeO2) was successfully synthesized through a facile co-precipitation method. High intense peak at 28.5° clearly indicated CeO2 cubic structure formation identified by using X-Ray diffraction. The optical phonon mode of F2g and oxygen vacancies mode was detected by using Raman spectra. The optical properties of CeO2 were detected with help of photoluminescence spectroscopy (PL). Fourier-transform infrared (FTIR) spectroscopy confirmed Ce-O vibration of CeO2 crystal existence. Surface morphology of CeO2 was thoroughly studied by using SEM images. HER and OER activity of pristine and Gd doped CeO2 was thoroughly investigated with the help of linear sweep voltammetry. Compared to pristine CeO2, high content of Gd doped CeO2 exhibited excellent HER and OER activity with low overpotential (99 mV for HER and 369 mV for OER) and small Tafel slope (211 mV/dec for HER and 183 mV/dec for OER). Addition of rare earth metal influenced the structural and catalytic properties of optimized metal oxide. Hence, the incorporation of Gadolinium in CeO2 plays a crucial role to enhance both HER and OER performance and it is one of the good candidates for energy conversion applications.

Capturing Metastable Oxide Semiconductors for Applications in Solar Energy Conversion.

ConspectusMany small bandgap semiconductors have been discovered or predicted to exist beyond the edges of stability, that is, accessible only as metastable solids that are thermodynamically unstable. In many cases, these metastable semiconductors have been revealed to have technologically promising properties for solar energy conversion, such as in photocatalysis or in photovoltaics. This Account presents a review of research results selected from my group and others in recent years on these semiconductors. Notably, these include the chemical systems of mixed-metal oxides (i.e., M'MOx; M = Ti(IV), Nb(V), or Ta(V) cation; M' = Ag(I), Cu(I), Sn(II), Pb(II), or Bi(III) cation), which have diverse structure types and compositions. High photocatalytic activities have been found for the light-driven reduction or oxidation of water as p- or n-type photoelectrodes, respectively, or as suspended powders in aqueous solutions. These have exhibited new combinations of favorable semiconductor properties, such as deep visible-light absorption, near-optimal band edge energies, defect tolerance, and functional carrier mobilities and charge separation. As described herein, this set of properties is inextricably linked to their metastable nature, that is, the crystalline structures and compositions needed for these characteristics lead naturally to thermodynamic instabilities.This Account focuses on current research efforts that have begun unlocking the potential of these semiconductors via new recent advances in (1) synthetic approaches that enable their preparation and (2) the understanding of structure-property relationships discovered at the precipices of stability that lead to the improved semiconductor properties. For example, low-temperature reactions have been developed to facilitate greater kinetic control, such as with the use of molten salts, and have been a key factor in preparing many of these semiconductors. As a result, a plethora of promising new mixed-metal oxide systems have been uncovered that exhibit band gaps spanning the range of photon energies from ∼1.3 to >3.0 eV. Especially relevant for visible-light applications are the Cu(I)- and Sn(II)-containing semiconductors. For example, n-type Sn(II)-titanates and p-type Cu(I)-niobates can be synthesized by flux methods and exhibit some of the smallest known visible-light band gaps that also maintain suitable conduction and valence band edges for driving the water-splitting half reactions. Kinetic stabilization of these metastable semiconductors against thermally driven phase segregation is increased with the formation of solid solutions for both the M and M' cation sites, leading to effective strategies to more finely tune their band gaps, band edge energies, and photoelectrochemical properties. Many unique and useful relationships are emerging between the synthesis and structures of metastable semiconductors and their physical properties, leading to more efficient solar energy conversion.

(Keynote) Decoupled Electrolysis for Water Splitting and Beyond

The storage of renewably-generated energy as hydrogen via the electrolysis of water is a fundamental cornerstone of a sustainable hydrogen economy. Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Decoupled Electrolysis (see, for example: Nature Chem. 2013, 5, 403-409; Science, 2014, 345, 1326-1330; J. Am. Chem. Soc. 2016, 138, 6707–6710; Joule, 2018, 2, 1390-1395; Adv. Energy Mater. 2020, 2002453) has the potential to overcome some of the challenges surrounding electrolysis using low and/or sporadic power inputs (especially those related to gas crossover) as the decoupling of the two half reactions of water splitting allows the oxygen and hydrogen evolution reactions to be performed at different times, in different places and at rates that are not linked to each other. In this talk, we shall investigate these claims for decoupled electrolysis (Electrochim. Acta, 2020, 331, 135255) and also explore the use of decoupling agents in other contexts such as redox flow batteries (Nature Chem. 2018, 10, 1042-1047) and electrosynthesis (Chem. Commun. 2018, 54, 1093-1096).