Electron bipolarons at the DMASnBr 3 –water interface: Effect on the photocatalytic hydrogen production

• In this article, we report on advanced molecular dynamics simulations of the atomistic DMASnBr3–water interface, which, coupled with a grand-canonical formulation of adsorbates and defects, elucidate the surface chemistry and reactivity of this novel water-stable perovskite and highlight the role of small electron bipolarons in photocatalytic hydrogen production. We find that the extremely acidic nature of the surface Br atoms does not allow for significant adsorption of protons at the interface under charge-neutral conditions. However, when electrons are accumulated on the surface, the formation of a small electron bipolaron in the form of a Sn-Sn dimer provides the required electron localization to drive adsorption of H, which is assimilated on surface Sn atoms as hydride. Finally, we estimate a favourable alignment between the bipolaron energy level and the H+/H2 redox level, which suggests the occurrence of a feasible route for hydrogen evolution, bypassing the common reaction mechanism.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Nyckelord

Small electron bipolarons

Ab initio molecular dynamics

Energy levels alignment

Photocatalysis

Water-stable metal halide perovskites

pH-dependent surface chemistry

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