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Title: Striving toward noble-metal-free photocatalytic water splitting: The hydrogenated-graphene-TiO 2 prototype

Graphane, graphone and hydrogenated graphene (HG) have been extensively studied in recent years due to their interesting properties and potential use in commercial and industrial applications. The present study reports investigation of hydrogenated graphene/TiO 2-x (HGT) nanocomposites as photocatalysts for H 2 and O 2 production from water without the assistance of a noble metal co-catalyst. By combination of several techniques, the morphologies, bulk/atomic structure and electronic properties of all the powders were exhaustively interrogated. Hydrogenation treatment efficiently reduces TiO 2 nanoparticles, while the graphene oxide sheets undergo the topotactic transformation from a graphene-like structure to a mixture of graphitic and turbostratic carbon (amorphous/disordered) upon altering the calcination atmosphere from a mildly reducing to a H 2-abundant environment. Remarkably, the hydrogenated graphene-TiO 2-x composite that results upon H 2-rich reduction exhibits the highest photocatalytic H 2 evolution performance equivalent to low loading of Pt (~0.12 wt%), whereas the addition of HG suppresses the O 2 production. As a result, we propose that such an enhancement can be attributed to a combination of factors including the introduction of oxygen vacancies and Ti 3+ states, retarding the recombination of charge carriers and thus, facilitating the charge transfer from TiO 2-x to themore » carbonaceous sheet.« less
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States)
Publication Date:
Report Number(s):
BNL-111615-2015-JA
Journal ID: ISSN 0897-4756; R&D Project: CO009; KC0302010
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 27; Journal Issue: 18; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1232700