TY - JOUR

T1 - Synergistic effect of p-type and n-type dopants in semiconductors for efficient electrocatalytic water splitting

AU - Kutlusoy, Tugce

AU - Divanis, Spyridon

AU - Pittkowski, Rebecca

AU - Marina, Riccardo

AU - Frandsen, Adrian M.

AU - Minhova-Macounova, Katerina

AU - Nebel, Roman

AU - Zhao, Dongni

AU - Mertens, Stijn F. L.

AU - Hoster, Harry

AU - Krtil, Petr

AU - Rossmeisl, Jan

PY - 2022

Y1 - 2022

N2 - The main challenge for acidic water electrolysis is the lack of active and stable oxygen evolution catalysts based on abundant materials, which are globally scalable. Iridium oxide is the only material which is active and stable. However, Ir is extremely rare. While both active materials and stable materials exist, those that are active are usually not stable and vice versa. In this work, we present a new design strategy for activating stable materials originally deemed unsuitable due to a semiconducting nature and wide band gap energy. These stable semiconductors cannot change oxidation state under the relevant reaction conditions. Based on DFT calculations, we find that adding an n-type dopant facilitates oxygen binding on semiconductor surfaces. The binding is, however, strong and prevents further binding or desorption of oxygen. By combining both n-type and p-type dopants, the reactivity can be tuned so that oxygen can be adsorbed and desorbed under reaction conditions. The tuning results from the electrostatic interactions between the dopants as well as between the dopants and the binding site. This concept is experimentally verified on TiO2 by co-substituting with different pairs of n- and p-type dopants. Our findings suggest that the co-substitution approach can be used to activate stable materials, with no intrinsic oxygen evolution activity, to design new catalysts for acid water electrolysis.

AB - The main challenge for acidic water electrolysis is the lack of active and stable oxygen evolution catalysts based on abundant materials, which are globally scalable. Iridium oxide is the only material which is active and stable. However, Ir is extremely rare. While both active materials and stable materials exist, those that are active are usually not stable and vice versa. In this work, we present a new design strategy for activating stable materials originally deemed unsuitable due to a semiconducting nature and wide band gap energy. These stable semiconductors cannot change oxidation state under the relevant reaction conditions. Based on DFT calculations, we find that adding an n-type dopant facilitates oxygen binding on semiconductor surfaces. The binding is, however, strong and prevents further binding or desorption of oxygen. By combining both n-type and p-type dopants, the reactivity can be tuned so that oxygen can be adsorbed and desorbed under reaction conditions. The tuning results from the electrostatic interactions between the dopants as well as between the dopants and the binding site. This concept is experimentally verified on TiO2 by co-substituting with different pairs of n- and p-type dopants. Our findings suggest that the co-substitution approach can be used to activate stable materials, with no intrinsic oxygen evolution activity, to design new catalysts for acid water electrolysis.

KW - OXYGEN EVOLUTION REACTION

KW - DENSITY-FUNCTIONAL THEORY

KW - PHOTOCATALYTIC ACTIVITY

KW - BAND-GAP

KW - TIO2

KW - OXIDES

KW - RUTILE

KW - NANOCRYSTALS

KW - PERSPECTIVE

KW - ADSORPTION

U2 - 10.1039/d2sc04585k

DO - 10.1039/d2sc04585k

M3 - Journal article

C2 - 36544721

VL - 13

SP - 13879

EP - 13892

JO - Chemical Science

JF - Chemical Science

SN - 2041-6520

IS - 46

ER -