Valence oscillation and dynamic active sites in monolayer NiCo hydroxides for water oxidation

Kang, Jian; Qiu, Xiaoyi; Hu, Qi; Zhong, Jun; Gao, Xiang; Huang, Rong; Wan, Chunru; Liu, Li Min; Duan, Xiangfeng; Guo, Lin

doi:10.1038/s41929-021-00715-w

Cited by 284 publications

(194 citation statements)

References 54 publications

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“…[34,35,40,41,74] Therefore, similar to previously reported LOM reaction mechanism on the active sites, the activated lattice oxygen in S-FeOOH would be considered as the active site. [41,74,75] The intermediates structures of FeOOH and S-FeOOH during OER process for AEM and LOM are presented in Figures S24 and S25, Supporting Information, respectively. The free energy diagram of FeOOH is presented in Figure 8d, demonstrating that the step FeOO*-O to FeO-* via AEM and the step FeOH*-OO to FeOH* via LOM mechanism exhibit the largest energy barrier (potential determining step (PDS)) among the studied steps, with the corresponding energy barrier of 1.98 and 2.92 eV, respectively.…”

Section: Density Functional Theory Calculationsmentioning

confidence: 99%

S‐Doping Triggers Redox Reactivities of Both Iron and Lattice Oxygen in FeOOH for Low‐Cost and High‐Performance Water Oxidation

Chen

Wang

Cheng

et al. 2022

Adv Funct Materials

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Developing low‐cost and highly efficient earth‐abundant oxygen evolution reaction (OER) electrocatalysts via an energy‐ and time‐saving method is of great significance to the generation of H2 from electrochemical water splitting, which is highly desirable but still challenging. Herein, a one‐step route to in situ grow S‐doped FeOOH vertical nanosheets on iron foam (IF) in 20 min under room temperature is shown. This facile and ultrafast method effectively modifies the surface of the IF into an S‐doped FeOOH layer, and a full‐Fe electrode (S‐FeOOH/IF) is achieved. Systematic experiments and characterizations demonstrate that the redox reactivities for both of the iron and lattice oxygen in FeOOH are sufficiently activated, leading to the dramatically improved intrinsic OER activity. The as‐obtained S‐FeOOH/IF exhibits a fascinating OER performance with a low overpotential of 244 at 10 mA cm−2. This work affords an efficient surface engineering strategy to drive commercial IF into cost‐efficient and robust earth‐abundant electrocatalysts for water oxidation, which has important implications for clean H2 production through a low‐carbon and environmentally friendly route.

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Section: Density Functional Theory Calculationsmentioning

confidence: 99%

S‐Doping Triggers Redox Reactivities of Both Iron and Lattice Oxygen in FeOOH for Low‐Cost and High‐Performance Water Oxidation

Chen

Wang

Cheng

et al. 2022

Adv Funct Materials

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“…Combined with the previous reports, the γ-NiOOH phase has an interlayer spacing of ≈7 Å and facilitates the intercalation of water or ions in-between the layers in the alkaline solution, which can significantly enhance the efficient evolution of oxygen. [52][53][54] Additionally, a broad band was detected between 850 and 1200 cm −1 in the Raman spectra upon cycling (Figure 4d). There might be two primary origins, the generation of superoxidic species (O-O − ) in the oxyhydroxide structure (NiOO − ) [55,56] and the oxidization of phosphorus species (H x PO y , P x O y ).…”

Section: Resultsmentioning

confidence: 99%

2D/2D Black Phosphorus/Nickel Hydroxide Heterostructures for Promoting Oxygen Evolution via Electronic Structure Modulation and Surface Reconstruction

Mei

Shang

et al. 2022

Advanced Energy Materials

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as one crucial technology for hydrogen production, has received intensive attention in recent years. The current progress, however, is still far away from industrial applications. The major concerns are associated with electrocatalysts, particularly for the half-reaction, oxygen evolution reaction (OER). An ideal catalyst toward OER should manifest a high catalytic efficiency but a low material cost. Compared to the dominate noble-metal-based electrocatalysts, transition metal compounds are expected to be promising candidates to replace noble metals, ascribed to their low production costs and comparable catalytic properties. [2] Among these, nickel (Ni)-based hydroxides have been regarded as one of the most active OER catalysts, particularly in alkaline electrolytes. [3] The catalytic property of the pristine nickel hydroxide (Ni(OH) 2 ), however, is yet far from satisfactory, [4] and further structural or chemical optimization is always demanded for promoting its OER performance. To date, several strategies have been employed for enhancing the catalytic performance of Ni(OH) 2 catalyst, including i) manipulating the size or dimensionality for more active sites, [5][6][7] ii) pairing with other OER-active counterparts for better activity, [8][9][10] iii) doping with heteroatoms (e.g., Fe, V, W, and Ce) to tailor the electronic structure and surface adsorption behaviors, [11][12][13][14][15][16][17] and iv) creating defective surfaces or interfaces. [18][19][20] Despite that significant efforts in regulating morphologies and/or structures have been undertaken, new 2D heterostructures provide another exciting opportunity for extending the application of 2D materials in energy conversionand storage devices, due to their flexibility in electronic structure modulations and surface chemistry regulations. Herein, by coupling liquid-exfoliated and mildly oxidized black phosphorus nanosheets (BP-NSs) with wet-chemically synthesized 2D nickel Ni(OH) 2 nanosheets (NH-NSs), 2D/2D heterostructured nanosheets (BNHNSs) are rationally constructed with a favorable transition of electron structure and desired intermediate adsorptions for alkaline oxygen evolution reaction (OER) catalysis. When used as an OER catalyst, to reach a current density of 10 mA cm −2 , the overpotential of 2D/2D BNHNSs is only 297 mV, corresponding to a considerable decrease of 22% and 34% compared with the individual 2D NH-NSs and 2D BP-NSs, respectively. The structural tracking at the initial reconstruction stage via time-dependent Raman spectra confirms that the phosphorus oxidization into the P-OH and the phase transformation into oxyhydroxide (NiOOH) significantly promote the electron transfer and electrocatalytic efficiency and thus endow the 2D/2D BNHNSs with much enhanced OER catalytic activity. This work offers new insights on the electron structure modulation of 2D-based heterostructures and opens new avenues for regulating the adsorption of emerging phosphorene-based materials for electrocatalysis.

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“…7f, and all calculated Gibbs free energies are based on Ni(Fe)OOH without considering the addition of Ndoped CNTs. [36][37][38] We start with a…”

Section: Resultsmentioning

confidence: 99%

Enhanced oxygen evolution catalyzed by in situ formed Fe-doped Ni oxyhydroxides in carbon nanotubes

et al. 2022

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Valence oscillation and dynamic active sites in monolayer NiCo hydroxides for water oxidation

Cited by 284 publications

References 54 publications

S‐Doping Triggers Redox Reactivities of Both Iron and Lattice Oxygen in FeOOH for Low‐Cost and High‐Performance Water Oxidation

S‐Doping Triggers Redox Reactivities of Both Iron and Lattice Oxygen in FeOOH for Low‐Cost and High‐Performance Water Oxidation

2D/2D Black Phosphorus/Nickel Hydroxide Heterostructures for Promoting Oxygen Evolution via Electronic Structure Modulation and Surface Reconstruction

Enhanced oxygen evolution catalyzed by in situ formed Fe-doped Ni oxyhydroxides in carbon nanotubes

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