Birnessite: A Layered Manganese Oxide To Capture Sunlight for Water-Splitting Catalysis

Lucht, Kevin P.; Mendoza-Cortés, José L.

doi:10.1021/acs.jpcc.5b07860

Cited by 80 publications

(118 citation statements)

References 39 publications

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“…3. In scenario 1K|1K, the energy splitting between the conduction band edges zeroes out because the potentials of the two layers are balanced now; the polaronic states located within the original band gap define a new valence band maximum and a new band gap about 2.0 eV, resembling the electronic structure of the triclinic phase with higher K concentration (KMn4O8) from a recent calculation (16). Because of the suitable band gap, this electronic structure has been proposed for PEC water splitting (16), but it may suffer from a weak optical absorption and a low hole mobility.…”

Section: Resultsmentioning

confidence: 69%

“…We argue that a surface electronic structure similar to scenario 0K|2K should be primarily responsible for the experimentally observed OER catalytic activity of the hexagonal birnessite. The well-crystallized triclinic birnessite, with more evenly distributed cation intercalation and the associated Mn(III), is similar to scenario 1K|1K (16), where Mn(III) is too stable to be an active site for OER catalysis. By contrast, in scenario 0K|2K the Mn(III) and Mn(IV) compete with each other, enabling the Mn cation to adapt its oxidation state to different intermediates during the OER cycle, as other OER catalysts do (11)(12)(13).…”

Section: Resultsmentioning

confidence: 86%

“…The role of water molecules is mainly as a structure stabilizer (15), removal of which causes little change to the electronic structure according to a recent computation (16). Hence, we choose the pure hexagonal MnO2 to study the intrinsic properties, without cation or water intercalation and with the experimental interlayer spacing.…”

Section: Resultsmentioning

confidence: 99%

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Redox properties of birnessite from a defect perspective

Peng

McKendry

Ding

et al. 2017

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

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Birnessite, a layered-structure MnO 2 , is an earth-abundant functional material with potential for various energy and environmental applications, such as water oxidation. An important feature of birnessite is the existence of Mn(III) within the MnO 2 layers, accompanied by interlayer charge-neutralizing cations. Using first-principles calculations, we reveal the nature of Mn(III) in birnessite with the concept of the small polaron, a special kind of point defect. Further taking into account the effect of the spatial distribution of Mn(III), we propose a theoretical model to explain the structure-performance dependence of birnessite as an oxygen evolution catalyst. We find an internal potential step which leads to the easy switching of the oxidation state between Mn(III) and Mn(IV) that is critical for enhancing the catalytic activity of birnessite. Finally, we conduct a series of comparative experiments which support our model.birnessite MnO 2 | small polaron | catalysis | water oxidation P hotoelectrochemical (PEC) splitting of water into H2 and O2 (artificial photosynthesis) provides an attractive way to harvest solar energy. The process consists of the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), both of which are facilitated with catalysts in practice. Currently, one of the biggest challenges is to develop a cheap and efficient catalyst for the former reaction with a low overpotential, which is still needed to overcome the kinetic barriers (already lowered by the catalyst) along the path from reactants to products. Birnessite, similar to the oxygen-evolving complex in Photosystem II for photosynthesis in regard to the coexistence of Mn(III) (nominal Mn 3+ ) and Mn(IV) (nominal Mn 4+ ) within its structure (1-3), has already shown a moderate catalytic performance with the overpotentials reported from 0.6 V to 0.8 V (4-8).Birnessite has the general formula Mx MnO2·1.5(H2O), composed of layers of edge-sharing MnO6 octahedra as shown in Fig. 1 for the hexagonal phase, and an interlayer of randomly distributed water molecules and metal (M) cations (like K + , Na + , and Ca 2+ ). With the charge balanced by the interlayer cations, some of the Mn cations within the MnO2 layer are reduced from Mn(IV) to Mn(III). The coexistence of Mn(IV) and Mn(III), and further the "balanced equilibrium" or low energy barrier between them, has been suspected to be a critical factor for its catalytic activity (1). The importance of the high-spin Mn(III), through its e 1 g electronic configuration, has been realized in other manganese oxides for OER catalysis (2, 9) and also follows the design principle of Suntivich et al. (10) that a near-unity eg occupancy may imply good OER catalytic activity. This easy switching of the oxidation state is also a typical behavior for the transition metal cation undergoing back and forth changes between several oxidation states in OER catalysts during the water oxidation cycle (11-13). OER catalysts like Co-and Ni-doped hematite (12) and cobalt oxides (13), as well as ...

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 86%

See 1 more Smart Citation

Redox properties of birnessite from a defect perspective

Peng

McKendry

Ding

et al. 2017

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

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“…The 2D nanosheets in Figure b are discretely interspersed by spherical particles with a similar morphology as the IrO 2 particles synthesized via the hydrothermal route (Figure S2). Nanosized IrO 2 particles are observed in TEM images to be sparsely loaded on the exterior of the hexagon birnessite, and the layers of the prepared Ir‐loaded Mn−Co catalyst become thinner than the layers of bulk Mn birnessite, which may cause the indirect band transition decreases as the number of layers are reduced . The TEM image of IrO 2 /Mn−Co(2 : 1)‐Bir in Figure d also clearly demonstrates that the obtained product is composed of thin layers and loaded by particles.…”

Section: Resultsmentioning

confidence: 95%

Effective Strain Engineering of IrO₂ Toward Improved Oxygen Evolution Catalysis through a Catalyst‐Support System

et al. 2019

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A template‐free, one‐step synthesis of nano‐IrO2 on a layered Mn−Co birnessite support was developed to induce the catalyst‐support interaction. The IrO2 nanoparticles were prepared with inherent crystal lattice strain, which is derived from the Ir‐O−Mn mismatch at the interface. The oxidation state of iridium is higher than IrIV, revealing the electron transfer to the substrate. On account of the crystal lattice distortion and electronic manipulations being favorable to the oxygen evolution reaction (OER), the as‐synthesized composite exhibited excellent OER activity and stability. The improved catalytic nature was followed by enhancement in the electrochemical active surface area, mass specific activity, and intrinsic activity. Moreover, the Tafel slope of 42 mV dec−1 reveals better reaction kinetics for IrO2/Mn−Co (2 : 1)‐birnessite than many previously reported catalysts despite the low precious noble metal content in the as‐synthesized composite. Conclusively, we have proven that the strain engineering holds vital importance in forming catalyst‐support interaction and rational design of catalysts.

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“…In particular, light‐matter interaction at surfaces has attracted interest for photonic and electronic molecular devices . The interaction processes leading to self‐assembled organic molecules are an important tool to engineer different components of such systems . One common scheme for demonstration of these devices employs the patterning of a thin film.…”

Section: Introductionmentioning

confidence: 99%

Surface Nonlinear Gratings by Direct Multiphoton Microscope Writing

Avalos-Hernández

Carriles

Domínguez-Juárez

2017

Physica Status Solidi (b)

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Thin film fabrication and patterning using organic molecules is of interest for technological and optoelectronic applications, among others. We demonstrate a new method to realize surface periodic patterning using femtosecond laser radiation from a multiphoton microscope. The laser is focused on organic films to generate a homogeneous 2D structure on a flat surface. The organic film was deposited onto microscope slides by immersion. From the gratings, the relative position of the nonlinearly diffracted first order maxima of second harmonic generation was measured. It is shown that nonlinear diffraction orders can be manipulated by the characteristics of the surface periodic patterning. It is possible to extend this writing scheme to arbitrary patterns and possibly curved surfaces with potential applications in couplers and waveguides. This method might also be useful to perform selective linear and nonlinear spectroscopy by modulating the linear and nonlinear activity of dyes deposited on the surface of microresonators or similar devices.

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Birnessite: A Layered Manganese Oxide To Capture Sunlight for Water-Splitting Catalysis

Abstract: We show a comprehensive study on the structure and electronic properties of a layered manganese oxide commonly known as birnessite. We present the effects of substituting different intercalated cations (

Cited by 80 publications

References 39 publications

Redox properties of birnessite from a defect perspective

Redox properties of birnessite from a defect perspective

Effective Strain Engineering of IrO₂ Toward Improved Oxygen Evolution Catalysis through a Catalyst‐Support System

Surface Nonlinear Gratings by Direct Multiphoton Microscope Writing

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Birnessite: A Layered Manganese Oxide To Capture Sunlight for Water-Splitting Catalysis

Abstract: We show a comprehensive study on the structure and electronic properties of a layered manganese oxide commonly known as birnessite. We present the effects of substituting different intercalated cations (

Cited by 80 publications

References 39 publications

Redox properties of birnessite from a defect perspective

Redox properties of birnessite from a defect perspective

Effective Strain Engineering of IrO2 Toward Improved Oxygen Evolution Catalysis through a Catalyst‐Support System

Surface Nonlinear Gratings by Direct Multiphoton Microscope Writing

Contact Info

Product

Resources

About

Effective Strain Engineering of IrO₂ Toward Improved Oxygen Evolution Catalysis through a Catalyst‐Support System