Universität zu Köln

Kim, Sungsoon, Ji, Seulgi, Kim, Kwang Hee, Roh, Seung Hun, Cho, Yoonjun ORCID: 0000-0002-2186-6239, Lee, Chang-Lyoul, Lee, Kug-Seung, Choi, Dae-Geun, Choi, Heechae ORCID: 0000-0002-9390-6607, Kim, Jung Kyu ORCID: 0000-0002-8218-0062 and Park, Jong Hyeok ORCID: 0000-0002-6629-3147 (2021). Revisiting surface chemistry in TiO2: A critical role of ionic passivation for pH-independent and anti-corrosive photoelectrochemical water oxidation. Chem. Eng. J., 407. LAUSANNE: ELSEVIER SCIENCE SA. ISSN 1873-3212

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Abstract

TiO2 photoanodes suffer from low catalytic activity and poor stability under acidic media for water oxidation. Here, we report pH-independent high-efficiency photoelectrochemical (PEC) water oxidation and prolonged stability via simple ionic passivation of rutile TiO2 (rTiO(2)) surface. The controlled surface passivation by hydroxide ions (OH -) onto the rTiO(2) surface (OH-rTiO(2)) enables extraordinarily high PEC performance and longterm durability independent of the pH value of electrolyte. The OH-rTiO(2) photoanode shows a charge transfer efficiency of similar to 100% at 1.23 V vs RHE over the entire pH range (pH 0 similar to pH 14) without incorporation of any cocatalysts, hole scavengers or overlayer, which implies that the molecular surface passivation by hydroxide ions successfully promotes the water oxidation reaction pathway. According to our density functional theory (DFT) calculations, the OH-rTiO(2) surface can possess increased hydroxide ion coverage, faster decay of the positive surface charge in acidic environments, and weakened H+ adsorption for pH > 7, which enable enhanced water oxidation performance independent of the pH value of the electrolyte. Thus, our report proves that the ionic passivation by hydroxide ions can affect PEC performances and durability of photoanode materials for pH-universal photoelectrochemical water oxidation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kim, Sungsoon UNSPECIFIED UNSPECIFIED UNSPECIFIED Ji, Seulgi UNSPECIFIED UNSPECIFIED UNSPECIFIED Kim, Kwang Hee UNSPECIFIED UNSPECIFIED UNSPECIFIED Roh, Seung Hun UNSPECIFIED UNSPECIFIED UNSPECIFIED Cho, Yoonjun UNSPECIFIED orcid.org/0000-0002-2186-6239 UNSPECIFIED Lee, Chang-Lyoul UNSPECIFIED UNSPECIFIED UNSPECIFIED Lee, Kug-Seung UNSPECIFIED UNSPECIFIED UNSPECIFIED Choi, Dae-Geun UNSPECIFIED UNSPECIFIED UNSPECIFIED Choi, Heechae UNSPECIFIED orcid.org/0000-0002-9390-6607 UNSPECIFIED Kim, Jung Kyu UNSPECIFIED orcid.org/0000-0002-8218-0062 UNSPECIFIED Park, Jong Hyeok UNSPECIFIED orcid.org/0000-0002-6629-3147 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-593413
DOI:	10.1016/j.cej.2020.126929
Journal or Publication Title:	Chem. Eng. J.
Volume:	407
Date:	2021
Publisher:	ELSEVIER SCIENCE SA
Place of Publication:	LAUSANNE
ISSN:	1873-3212
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language TOTAL-ENERGY CALCULATIONS; OXIDE; MECHANISMS; TITANIUM; RUTILE; LAYER Multiple languages Engineering, Environmental; Engineering, Chemical Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/59341