2D CoOOH Sheet-Encapsulated Ni2P into Tubular Arrays Realizing 1000 mA cm−2-Level-Current-Density Hydrogen Evolution Over 100 h in Neutral Water

Zhang, Shucong; Wang, Wenbin; Hu, Feilong; Mi, Yan; Wang, Shuzhe; Liu, Youwen; Ai, Xiaomeng; Fang, Jiakun; Li, Huiqiao; Zhai, Tianyou

doi:10.1007/s40820-020-00476-4

Cited by 95 publications

(59 citation statements)

References 61 publications

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“…Furthermore, the thickness of the CoOOH shell is ≈80–90 nm, which cannot only reduce the loss of CoP core, but also may improve the utilization rate of CoOOH shell, thus effectively decreasing the adhesion of gas, and accelerating the bubbles’ release. [ 24,25 ] Moreover, high‐resolution TEM (HRTEM) images (Figure 2f,g) confirm obvious crystalline planes. The lattice distances of 0.357 and 0.198 nm unambiguously correspond to the (101) plane of CoP and the (104) plane of CoOOH, respectively.…”

Section: Resultsmentioning

confidence: 98%

Oxygen Vacancy and Core–Shell Heterojunction Engineering of Anemone‐Like CoP@CoOOH Bifunctional Electrocatalyst for Efficient Overall Water Splitting

Zhang

Shan

Wang

et al. 2022

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Synthesizing cost-efficient and robust bifunctional electrocatalysts for both neutral and alkaline water splitting is highly desired, but still remains a great challenge due to the sluggish hydrogen/oxygen evolution reaction (HER/OER) kinetics. Currently, noble Pt, Ru, and Ir-based catalysts are the most efficient ones, but their high cost and scarcity greatly restrict their broad applications. [2] Therefore, enormous efforts have been made toward developing suitable and cheaper catalysts with earthabundant materials for commercial applications. In the past years, a large number of non-noble-metal based catalysts, including transition metal phosphides, nitrides, carbides, and oxides, had good development prospects in catalytic fields. [3] Among these, transition metal phosphides (TMPs) such as Fe x P, Co x P, and Ni x P are promising and considered as the most probable alternatives to the noblemetal based catalysts due to their abundant reserves, high stability, non-toxicity, fast charge transfer, and electrical conductivity. [4] However, many studies demonstrated that TMPs exhibited excellent hydrogen evolution reaction (HER) activity (it may be attributed to the reported hydrogenase-like catalytic mechanism), [5] but poor oxygen evolution reaction (OER) activity. So, it is an urgent to improve their catalytic behavior. There are two effective strategies to solve the above problems:Constructing cost-efficient and robust bifunctional electrocatalysts for both neutral and alkaline water splitting is highly desired, but still affords a great challenge, due to sluggish hydrogen/oxygen evolution reaction (HER/OER) kinetics. Herein, an in situ integration engineering strategy of oxygen-vacancy and core-shell heterojunction to fabricate an anemone-like CoP@CoOOH core-shell heterojunction with rich oxygen-vacancies supported on carbon paper (CoP@CoOOH/CP), is described. Benefiting from the synergy of CoP core and oxygen-vacancy-rich CoOOH shell, the as-obtained CoP@CoOOH/CP catalyst displays low overpotentials at 10 mA cm -2 for HER (89.6 mV/81.7 mV) and OER (318 mV/200 mV) in neutral and alkaline media, respectively. Notably, a two-electrode electrolyzer, using CoP@CoOOH/CP as bifunctional catalyst to achieve 10 mA cm -2 , only needs low-cell voltages in neutral (1.65 V) and alkaline (1.52 V) electrolyte. Besides, systematically experimental and theoretical results reveal that the core-shell heterojunction efficiently accelerates the catalytic kinetics and strengthens the structural stability, while rich oxygen-vacancies efficiently decrease the kinetic barrier and activation energy, and reduce the energy barrier of the rate-determiningstep for OER intermediates, thus intrinsically boosting OER performance. This work clearly demonstrates that oxygen-vacancy and core-shell heterojunction engineering provide an effective strategy to design highly-efficient non-precious, bi-functional electrocatalysts for pH-universal water splitting.The ORCID identification number(s) for the author(s) of this article can be found under h...

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Section: Resultsmentioning

confidence: 98%

Oxygen Vacancy and Core–Shell Heterojunction Engineering of Anemone‐Like CoP@CoOOH Bifunctional Electrocatalyst for Efficient Overall Water Splitting

Zhang

Shan

Wang

et al. 2022

Small

111

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“…As demonstrated by some binder-free catalysts, they show superior stability under HCD conditions. [49,76] For example, Zhang et al report a catalyst composed of CoOOH encapsulated Ni 2 P tubular arrays, which shows a stability over 100 h at 1200 mA cm -2 for HER. [76] They show that such a catalyst buffers the shock of electrolyte convection and hydrogen bubble rupture through release of stress.…”

Section: Effect Of Current Density On Catalytic Performancementioning

confidence: 99%

Recent Advances in Design of Electrocatalysts for High‐Current‐Density Water Splitting

et al. 2022

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Electrochemical water splitting technology for producing "green hydrogen" is important for the global mission of carbon neutrality. Electrocatalysts with decent performance at high current densities play a central role in the industrial implementation of this technology. The field has advanced immensely in recent years, as witnessed by many types of catalysts have been designed and synthesized which work at industrially-relevant current densities (> 200 mA cm -2 ). Note that the activity and stability of catalysts can be influenced by their local reaction environment, which are closely related to the current density. By discussing recent advances in this field, we summarize several key aspects that affect the catalytic performance for high-current-density electrocatalysis, including dimensionality of catalysts, surface chemistry, electron transport path, morphology, and catalyst-electrolyte interplay. We highlight the multiscale design strategy that considers these aspects comprehensively for developing highcurrent-density catalysts. We also put forward out perspectives on the future directions in this emerging field.

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“…However, the practical water electrolysis is limited by the sluggish kinetics at cathode (hydrogen evolution reaction, HER) and anode (oxygen evolution reaction, OER) [5][6][7][8][9][10][11]. For industrial WS catalyst, these requirements must be met: (1) stable and high active sites at large current density [12]; (2) continuous intensive gas evolution [13,14]; (3) fast electron transfer [15,16]; (4) low-cost and accessibility [17,18]. Although some progress has been made, it is still a challenge to explore high-performance WS catalysts, especially in industrial environment.…”

Section: H O Cmentioning

confidence: 99%

Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition

et al. 2021

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Constructing heterojunction is an effective strategy to develop high-performance non-precious-metal-based catalysts for electrochemical water splitting (WS). Herein, we design and prepare an N-doped-carbon-encapsulated Ni/MoO2 nano-needle with three-phase heterojunction (Ni/MoO2@CN) for accelerating the WS under industrial alkaline condition. Density functional theory calculations reveal that the electrons are redistributed at the three-phase heterojunction interface, which optimizes the adsorption energy of H- and O-containing intermediates to obtain the best ΔGH* for hydrogen evolution reaction (HER) and decrease the ΔG value of rate-determining step for oxygen evolution reaction (OER), thus enhancing the HER/OER catalytic activity. Electrochemical results confirm that Ni/MoO2@CN exhibits good activity for HER (ƞ-10 = 33 mV, ƞ-1000 = 267 mV) and OER (ƞ10 = 250 mV, ƞ1000 = 420 mV). It shows a low potential of 1.86 V at 1000 mA cm−2 for WS in 6.0 M KOH solution at 60 °C and can steadily operate for 330 h. This good HER/OER performance can be attributed to the three-phase heterojunction with high intrinsic activity and the self-supporting nano-needle with more active sites, faster mass diffusion, and bubbles release. This work provides a unique idea for designing high efficiency catalytic materials for WS.

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2D CoOOH Sheet-Encapsulated Ni2P into Tubular Arrays Realizing 1000 mA cm−2-Level-Current-Density Hydrogen Evolution Over 100 h in Neutral Water

Cited by 95 publications

References 61 publications

Oxygen Vacancy and Core–Shell Heterojunction Engineering of Anemone‐Like CoP@CoOOH Bifunctional Electrocatalyst for Efficient Overall Water Splitting

Oxygen Vacancy and Core–Shell Heterojunction Engineering of Anemone‐Like CoP@CoOOH Bifunctional Electrocatalyst for Efficient Overall Water Splitting

Recent Advances in Design of Electrocatalysts for High‐Current‐Density Water Splitting

Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition

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