Increasing the optical response of TiO<sub>2</sub> and extending it into the visible region through surface activation with highly stable Cu<sub>5</sub> clusters

Lara‐Castells, María Pilar de; Hauser, Andreas; Ramallo‐López, José M.; Buceta, David; Giovanetti, Lisandro J.; López‐Quintela, M. Arturo; Requejo, Félix G.

doi:10.1039/c9ta00994a

Cited by 46 publications

(77 citation statements)

References 88 publications

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“…de Lara-Castells et al found that the Cu 5 cluster, when being deposited on the surface of TiO 2 , would donate an electron to Ti, favoring the formation of the active Ti 3+ species for CO 2 reduction. 22 , 27 A similar conclusion was also drawn by Seriani et al, who studied a system of TiO 2 deposited by Cu clusters (Cu x , x = 1–4). The authors also emphasized the importance of gap states created by the introduced Cu species, which could improve the optical response by reducing the band gap.…”

Section: Introductionsupporting

confidence: 77%

“… 17 − 19 Therefore, a relatively low loading amount of Cu and supports with high specific surface area are often used, and a great effort was recently devoted to synthesize CuO x /TiO 2 with Cu in the morphologies of subnanoclusters or even a single atom. 20 − 22 After being introduced to TiO 2 , Cu species would bring about several benefits. The primary one is that the usable solar energy for photocatalysis could be extended to the visible light region.…”

Section: Introductionmentioning

confidence: 99%

“…The primary one is that the usable solar energy for photocatalysis could be extended to the visible light region. 22 − 24 The secondary one is that the activity, particularly for reduction of CO 2 into CO, could be promoted largely from a few to dozens of times. 10 , 25 In addition, the selectivity toward hydrogen enriched products like CH 3 OH, CH 4 , and H 2 could be enhanced remarkably.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

et al. 2020

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Incorporation of earth-abundant Cu is one of the most important approaches to improve the practicability of TiO 2 for photoreduction of CO 2 into value-added solar fuels. However, the molecular insight on the role of Cu is complicated and far from understood. We performed a first principle calculation on the anatase (101) surface modified by a single Cu atom deposited on the surface (Cu S ) or doped in the lattice (Cu L ). It is demonstrated the Cu L is clearly more stable than the Cu S and could promote the formation of oxygen vacancy (Vo) greatly. The Cu S plays a role of donor, while the Cu L is electronically deficient and becomes a global electron trapper. If a Vo is introduced, the excess electrons would immigrate to the empty gap state of the Cu L and make it half-filled in some case, which implies its metallic characters and improved conductivity; meanwhile, the formation of Ti 3+ is suppressed. Judging from the adsorption energies, it is the Vo that primarily improves the adsorption of CO 2 in both linear and bent states, and the Cu S could hardly stabilize CO 2 more, while the promotion effect of Vo could even be counteracted by the Cu L due to its electronic deficiency. The reduction pathways (CO 2 * → CO* + O*) show that, with the assistance of the Cu S , linear CO 2 could directly transform into the carbonate-like geometry vertically binding to the surface, and the intermediate configuration of the bent CO 2 horizontally bridging the Vo could be successfully skipped. Therefore, the barrier of the rate-determining transformation could be lowered from 0.75 to 0.39 eV. Furthermore, it is found the strong adsorption of the produced CO by the Cu S might retard the smooth going of the catalytic process.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

et al. 2020

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“… 41 , 42 Specifically, we employ a dispersion-corrected DFT-D3 ansatz , 43 , 44 given its excellent performance in describing the adsorption of subnanometer silver and copper clusters on oxide surfaces. 41 , 42 , 45 Structural optimizations and the calculation of interaction energies are carried out with the Perdew–Burke–Ernzerhof (PBE) density functional 46 and the Becke-Johnson (BJ) damping 43 for the D3 dispersion correction. Minor energy differences and the same trends were found when replacing the PBE functional by the PBEsol 47 , 48 counterpart in the DFT-D3 ansatz .…”

Section: Methodsmentioning

confidence: 99%

Thermally Induced Diffusion and Restructuring of Iron Triade (Fe, Co, Ni) Nanoparticles Passivated by Several Layers of Gold

et al. 2020

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The temperature-induced structural changes of Fe–, Co–, and Ni–Au core–shell nanoparticles with diameters around 5 nm are studied via atomically resolved transmission electron microscopy. We observe structural transitions from local toward global energy minima induced by elevated temperatures. The experimental observations are accompanied by a computational modeling of all core–shell particles with either centralized or decentralized core positions. The embedded atom model is employed and further supported by density functional theory calculations. We provide a detailed comparison of vacancy formation energies obtained for all materials involved in order to explain the variations in the restructuring processes which we observe in temperature-programmed TEM studies of the particles.

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“…For this purpose, we have selected the particular case of the Cu 5 cluster. This choice is motivated by a recent work 9 demonstrating via ab initio modeling and selected experiments that the deposition of a single monolayer of highly stable Cu 5 clusters onto a TiO 2 surface makes it an innovative visible-light photo-active material. Much more energy can be harvested from sunlight, and the coated titanium dioxide stores this energy temporarily in the form of charge pairs—electrons and holes—which is a perfect prerequisite for follow-up chemistry.…”

Section: Introductionmentioning

confidence: 99%

On the Stability of Cu₅ Catalysts in Air Using Multireference Perturbation Theory

et al. 2019

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An ab initio study of the interaction of O 2 , the most abundant radical and oxidant species in the atmosphere, with a Cu 5 cluster, a new generation atomic metal catalyst, is presented. The open-shell nature of the reactant species is properly accounted for by using the multireference perturbation theory, allowing the experimentally confirmed resistivity of Cu 5 clusters toward oxidation to be investigated. Approximate reaction pathways for the transition from physisorption to chemisorption are calculated for the interaction of O 2 with quasi-iso-energetic trapezoidal planar and trigonal bipyramidal structures. Within the multireference approach, the transition barrier for O 2 activation can be interpreted as an avoided crossing between adiabatic states (neutral and ionic), which provides new insights into the charge-transfer process and gives better estimates for this hard to localize and therefore often neglected first intermediate state. For Cu 5 arranged in a bipyramidal structure, the O–O bond cleavage is confirmed as the rate-determining step. However, for planar Cu 5 , the high energy barrier for O 2 activation, related to a very pronounced avoided crossing when going from physisorption to chemisorption, determines the reactivity in this case.

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Increasing the optical response of TiO₂ and extending it into the visible region through surface activation with highly stable Cu₅ clusters

Abstract: The photoabsorption of TiO2 in the UV gets enhanced and extended to the visible region by decoration with highly stable Cu5 clusters.

Cited by 46 publications

References 88 publications

Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

Thermally Induced Diffusion and Restructuring of Iron Triade (Fe, Co, Ni) Nanoparticles Passivated by Several Layers of Gold

On the Stability of Cu₅ Catalysts in Air Using Multireference Perturbation Theory

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Increasing the optical response of TiO2 and extending it into the visible region through surface activation with highly stable Cu5 clusters

Abstract: The photoabsorption of TiO2 in the UV gets enhanced and extended to the visible region by decoration with highly stable Cu5 clusters.

Cited by 46 publications

References 88 publications

Mechanistic Understanding on the Role of Cu Species over the CuOx/TiO2 Catalyst for CO2 Photoreduction

Mechanistic Understanding on the Role of Cu Species over the CuOx/TiO2 Catalyst for CO2 Photoreduction

Thermally Induced Diffusion and Restructuring of Iron Triade (Fe, Co, Ni) Nanoparticles Passivated by Several Layers of Gold

On the Stability of Cu5 Catalysts in Air Using Multireference Perturbation Theory

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Product

Resources

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Increasing the optical response of TiO₂ and extending it into the visible region through surface activation with highly stable Cu₅ clusters

Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

Mechanistic Understanding on the Role of Cu Species over the CuO_x/TiO₂ Catalyst for CO₂ Photoreduction

On the Stability of Cu₅ Catalysts in Air Using Multireference Perturbation Theory