Intrinsic Charge Polarization in Bi 19 S 27 Cl 3 Nano Roads Promotes Selective C-C Coupling Reaction During Photoreduction of CO 2 to Ethanol.

Obtaining multicarbon products via CO 2 photoreduction is a major catalytic challenge involving multielectron mediated C-C bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO 2 conversion efficiency and product selectivity. Alternatively, robust metal centres having asymmetric charge distribution can effectuate C-C coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, we present a novel photocatalyst, Bi 19 S 27 Cl 3 , which selectively converts CO 2 to a C 2 product, ethanol, in high yield under visible light irradiation. Structural analysis through Transmission Electron Microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy reveal the presence of charge polarized bismuth centres in Bi 19 S 27 Cl 3 , which is well complemented by DFT calculation. The intrinsic electric field induced by charge polarized bismuth centres renders better separation efficiency of photogenerated electron-hole pair. Furthermore, charge polarized centres yield better adsorption of CO* intermediate and accelerate the rate determining C-C coupling step through the formation of OCCOH intermediate. Formation of these intermediates was experimentally mapped by in-situ FTIR spectroscopy and further confirmed by theoretical calculation. This article is protected by copyright. All rights reserved.