Selective Seawater Splitting Using Pyrochlore Electrocatalyst

Gayen, Pralay; Saha, Sayantani; Ramani, Vijay

doi:10.1021/acsaem.0c00383

Cited by 93 publications

(90 citation statements)

References 26 publications

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“…Chloride is present in seawater at high concentrations (∼0.5 M), and its oxidation products, such as Cl 2 and OCl − , are toxic and should be minimized to achieve maximum OER selectivity. The reactions are as follows: 52

2 H_{2} normalO \to 4 H^{+} + O_{2} + 4 e^{-} E = 1.23 normalV vs RHE ((), acidic media),

\begin{matrix} centertrue \\ 4 {OH}^{-} \to 2 {normalH}_{2} O + {normalO}_{2} + 4 {normale}^{-} & E = 1.23 V vs RHE (alkaline media), \end{matrix}

\begin{matrix} centertrue \\ 2 {Cl}^{-} \to {Cl}_{2} + 2 {normale}^{-} & E = 1.36 V vs RHE (acidic media), \end{matrix}

\begin{matrix} centertrue \\ {Cl}^{-} + 2 {OH}^{-} \to {OCl}^{-} + {normalH}_{2} O + 2 {normale}^{-} & E = 1.36 V vs RHE (alkaline media) \end{matrix} .

…”

Section: Metal Phosphides As Bifunctional Catalyst For Her and Oermentioning

confidence: 99%

Promotion effect of metal phosphides towards electrocatalytic and photocatalytic water splitting

Han

Chen

Fan

et al. 2021

EcoMat

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Hydrogen evolution from water splitting over semiconductors has been considered one of the most promising ways to address energy shortages and environmental pollution. Searching for low‐cost, highly efficient, and durable catalysts is the key to improve the hydrogen production rate. Expensive noble metals, such as Pt and Au, are generally loaded onto semiconductors to promote photocatalytic activity. Metal phosphides are promising candidates to replace noble metals in hydrogen generation via electrocatalytic or photocatalytic water splitting due to their low hydrogen‐producing overpotential, tunable electronic structure, high electrical conductivity, and low price. In this review article, the characteristics and synthetic methods of metal phosphides are briefly introduced, and the development of metal phosphides for electrocatalytic or photocatalytic water splitting is presented. Finally, the challenges and future directions of metal phosphides are discussed.

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2 H_{2} normalO \to 4 H^{+} + O_{2} + 4 e^{-} E = 1.23 normalV vs RHE ((), acidic media),

\begin{matrix} centertrue \\ 4 {OH}^{-} \to 2 {normalH}_{2} O + {normalO}_{2} + 4 {normale}^{-} & E = 1.23 V vs RHE (alkaline media), \end{matrix}

\begin{matrix} centertrue \\ 2 {Cl}^{-} \to {Cl}_{2} + 2 {normale}^{-} & E = 1.36 V vs RHE (acidic media), \end{matrix}

\begin{matrix} centertrue \\ {Cl}^{-} + 2 {OH}^{-} \to {OCl}^{-} + {normalH}_{2} O + 2 {normale}^{-} & E = 1.36 V vs RHE (alkaline media) \end{matrix} .

…”

Section: Metal Phosphides As Bifunctional Catalyst For Her and Oermentioning

confidence: 99%

Promotion effect of metal phosphides towards electrocatalytic and photocatalytic water splitting

Han

Chen

Fan

et al. 2021

EcoMat

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“…The electrochemical measurements were carried out using a threeelectrode configuration in a five-neck electrochemical cell with suitable openings for the working, counter, and reference electrodes, the gas purge line inlet, and a gas outlet (Pine Instruments, AKCELL3) (23,33,34). The thinfilm electrodes for catalyst evaluation were prepared as detailed by us previously (19,20,35). The pseudoreference electrode was selected and the low-temperature tests were carried out based on the protocols reported by Compton and coworkers (9).…”

Section: Methodsmentioning

confidence: 99%

“…Catalyst degradation by the dissolution of Ru from Pb 2 Ru 2 O 7−δ under electrolyzer operating conditions was also investigated. No such dissolution was observed, suggesting that dissolution, if any, was under the 100-ppb detection limit of our inductive coupled plasma optical emission spectrometer (20). The actual proof-ofconcept electrolyzer setup used for the experiment is shown in SI Appendix, Fig.…”

Section: Significancementioning

confidence: 99%

“…S6) on this electrocatalyst and is further discussed in SI Appendix, section S6.3. The higher OER activity for Pb 2 Ru 2 O 7−δ (higher oxygen vacancy concentration, SI Appendix, section S6.1 and S6.3) as compared to benchmark RuO 2 was also attributed to facilitated water dissociation mediated by surface lattice oxygen vacancy quenching and increased bulk conductivity (20,21). The OER activities for all of the electrodes were also compared upon application of a constant overpotential (200 mV) as depicted in Fig.…”

Section: Significancementioning

confidence: 99%

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Fuel and oxygen harvesting from Martian regolithic brine

Gayen

Sankarasubramanian

Ramani

2020

Proc. Natl. Acad. Sci. U.S.A.

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NASA’s current mandate is to land humans on Mars by 2033. Here, we demonstrate an approach to produce ultrapure H2 and O2 from liquid-phase Martian regolithic brine at ∼−36 °C. Utilizing a Pb2Ru2O7−δ pyrochlore O2-evolution electrocatalyst and a Pt/C H2-evolution electrocatalyst, we demonstrate a brine electrolyzer with >25× the O2 production rate of the Mars Oxygen In Situ Resource Utilization Experiment (MOXIE) from NASA’s Mars 2020 mission for the same input power under Martian terrestrial conditions. Given the Phoenix lander’s observation of an active water cycle on Mars and the extensive presence of perchlorate salts that depress water’s freezing point to ∼−60 °C, our approach provides a unique pathway to life-support and fuel production for future human missions to Mars.

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“…The maximum hydrogen evolution reaction (HER) rate for EC and fuel cell is observed with Pt electrocatalyst (Nørskov et al, 2004; Ojha, Saha, Dagar, & Ganguli, 2018; Xie & Xie, 2015; H. Xu, Ci, Ding, Wang, & Wen, 2019; Zheng, Jiao, Vasileff, & Qiao, 2018). The most active and stable electrocatalysts for oxygen evolution reaction (OER) for EC are with Ru‐ or Ir‐based electrocatalysts (Gayen, Saha, Bhattacharyya, & Ramani, 2020; Gayen, Saha, & Ramani, 2020; Kishor et al, 2015; Sulay, Koshal, Sri, & Ganesh, 2016). The best performing lithium‐ion battery contains lithium and cobalt as a major material (Yoshino, 2012).…”

Section: Introductionmentioning

confidence: 99%

Stabilization of non‐native polymorphs for electrocatalysis and energy storage systems

Saha

Gupta

Pala

2020

WIREs Energy & Environment

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Evolution in material centric devices like batteries and electrocatalytic reactors have predominantly been made possible via the exploitation of the thermodynamic ground state of pristine or defective bulk crystal, referred to as the “Native polymorph” (NP) here. A significant increase in the material search space is possible by utilizing “Non‐Native polymorphs (NNP),” which are materials that have different translational symmetry with respect to NP. As the NNP have a distinct coordination structure from that of the NP, critical material properties can be anticipated to be different, making NNP a potential substitute material for the aforementioned applications, which are the focus of this review. To obtain a structure–function relationship, systematic approaches to the synthesis of NNP has been demonstrated. Following certain generalities behind NNP, we classify synthesis techniques into few categories with the hope of rationalizing the underlying mechanism of these synthesis and stabilization strategies. We discuss the utility of NNPs in the context of electrochemical water electrocatalytic reactions. Typically, the NNPs have more open volume space enabling lower lithium‐ion diffusion barrier, higher lithium‐ion binding energies, thereby making NNP efficient in the context of energy storage material. However, NNP have lesser stability than the NP and methods to calibrate and improve the stability of NNP are important. Overall, the discussion of polymorphic materials by demarcating them as NP and NNP provides a systematic approach towards modulating material properties as a trade‐off between thermodynamics and kinetics of physicochemical processes. Finally, the challenges and perspectives in this emerging field are discussed. This article is categorized under: Fuel Cells and Hydrogen > Science and Materials Energy Research & Innovation > Science and Materials Energy and Development > Science and Materials

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Selective Seawater Splitting Using Pyrochlore Electrocatalyst

Cited by 93 publications

References 26 publications

Promotion effect of metal phosphides towards electrocatalytic and photocatalytic water splitting

Promotion effect of metal phosphides towards electrocatalytic and photocatalytic water splitting

Fuel and oxygen harvesting from Martian regolithic brine

Stabilization of non‐native polymorphs for electrocatalysis and energy storage systems

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