Toward Ambitious Multiscale Modeling of Nanocrystal Catalysts for Water Splitting

Understanding the Structural and Electronic Properties of Photoactive Tungsten Oxide Nanoparticles from Density Functional Theory and GW Approaches

“…[6][7][8] In this context, setting up a reliable but still affordable methodology capable to deliver accurate information on the structure, the stability and the band-edge offsets of realistic nanocrystals is crucial for the design of efficient NPs for photocatalytic applications. 9 A proper modelling of NPs usually implies to tackle two main issues: (i) the construction of suitable structural models at the atomistic scale that are able to capture both the effects of morphology and size, which is often done by following top-down or bottom-up approaches; and (ii) the setup of a high precise and unbiased approach which can be employed to determine the electronic properties of NPs at the nanoscale level within an affordable computational cost. TiO 2 NPs constitute by far the most studied photocatalytic material, 10,11 although the need for UV radiation makes it inappropriate for large scale water splitting applications.…”

“…At this size, the effects of quantum confinement facilitate the transfer of charge carriers. , This implies that the size and morphology of NPs are two important factors in determining their electronic structure and, hence, their potential use as photocatalysts . The effect of the structural features can be phenomenologically observed by experiments, but a deep understanding and, more importantly, a systematic rationalization of the structure–property relationships are not straightforward and require relying on large-scale atomistic simulations based on accurate theoretical methods and realistic structural models. − In this context, setting up a reliable but still affordable methodology capable to deliver accurate information on the structure, the stability, and the band-edge offsets of realistic nanocrystals is crucial for the design of efficient NPs for photocatalytic applications . A proper modeling of NPs usually implies tackling of two main issues: (i) the construction of suitable structural models at the atomistic scale that are able to capture both the effects of morphology and size, which is often done by following top-down or bottom-up approaches, and (ii) the setup of a highly precise and unbiased approach, which can be employed to determine the electronic properties of NPs at the nanoscale level within an affordable computational cost.…”

Dynamics of Water Dissociative Adsorption on TiO2 Anatase (101) at Monolayer Coverage and Below

“…Artificial photosynthesis aims at the efficient conversion and storage of solar energy to fuels or high-energy chemicals. , Water splitting into oxygen and molecular hydrogen and reduction of carbon dioxide to methanol or other products are both reverse combustion processes that can be enhanced by combining sunlight and photoelectrocatalysis. − To this end, several semiconductors have been investigated as potential photocatalysts (CdS, ZrO 2 , Ga 2 O 3 , and Cu 2 O are few examples). − Among them, titania (TiO 2 ) has emerged as a sustainable photoelectrode thanks to its low cost, stability, and nontoxicity. − Moreover, nanostructured titania has proven to be very effective in a large variety of photocatalytic applications in aqueous solutions from water splitting to photodegradation of organic pollutants. − In this framework, elucidating the structure and reactivity of titania–water interfaces is thus crucial for improving the efficiency and selectivity of solar-to-fuel processes, especially in an aqueous environment. Among TiO 2 polymorphs, anatase is the most relevant because it is the most stable at the nanoscale, and its (101) surface termination is the most exposed in nanoparticles. ,− Several experimental and theoretical studies have addressed the reactivity of water on this facet, − but there are still open questions such as the roles of undercoordinated fivefold Ti surface species (Ti 5C ) and water coverage (θ = no.…”