University of Oulu

RSC Adv., 2020,10, 3693, https://doi.org/10.1039/D0RA07078E

Synergistic effect of Ni–Ag–rutile TiO₂ ternary nanocomposite for efficient visible-light-driven photocatalytic activity

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Author: Leukkunen, Petri M.1; Rani, Ekta1; Sasikala Devi, Assa Aravindh1;
Organizations: 1Nano and Molecular Systems Research Unit, University of Oulu, Finland
2Canadian Light Source, 44 Innovation Blvd., Saskatoon, Saskatchewan S7N 2V3, Canada
3School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, Henan, China
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.3 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020112092212
Language: English
Published: Royal Society of Chemistry, 2020
Publish Date: 2020-11-20
Description:

Abstract

P25 comprising of mixed anatase and rutile phases is known to be highly photocatalytically active compared to the individual phases. Using a facile wet chemical method, we demonstrate a ternary nanocomposite consisting of Ni and Ag nanoparticles, decorated on the surface of XTiO₂ (X: P25, rutile (R)) as an efficient visible-light-driven photocatalyst. Contrary to the current perspective, RTiO₂-based Ni–Ag–RTiO₂ shows the highest activity with the H₂ evolution rate of ∼86 μmol g⁻¹ W⁻¹ h⁻¹@535 nm. Together with quantitative assessment of active Ni, Ag and XTiO₂ in these ternary systems using high energy synchrotron X-ray diffraction, transmission electron microscopy coupled energy dispersive spectroscopy mapping evidences the metal to semiconductor contact via Ag. The robust photocatalytic activity is attributed to the improved visible light absorption, as noted by the observed band edge of ∼2.67 eV corroborating well with the occurrence of Ti³⁺ in Ti 2p XPS. The effective charge separation due to intimate contact between Ni and RTiO₂ via Ag is further evidenced by the plasmon loss peak in Ag 3d XPS. Moreover, density functional theory calculations revealed enhanced adsorption of H₂ on Ti₈O₁₆ clusters when both Ag and Ni are simultaneously present, owing to the hybridization of the metal atoms with d orbitals of Ti and p orbitals of O leading to enhanced bonding characteristics, as substantiated by the density of states. Additionally, the variation in the electronegativity in Bader charge analysis indicates the possibility of hydrogen evolution at the Ni sites, in agreement with the experimental observations.

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Series: RSC advances
ISSN: 2046-2069
ISSN-E: 2046-2069
ISSN-L: 2046-2069
Volume: 10
Issue: 60
Pages: 36930 - 36940
DOI: 10.1039/d0ra07078e
OADOI: https://oadoi.org/10.1039/d0ra07078e
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
221 Nanotechnology
114 Physical sciences
Subjects:
Funding: We acknowledge the European Regional Development Funding and the Oulu Council. The authors thank the Center of Microscopy and Nanotechnology of the University of Oulu. Computing resources were provided by CSC – IT Center for Science, Finland. Academy of Finland grant # 311934 is acknowledged. Part of the research described in this paper was performed at the Canadian Light Source, a national research facility of the University of Saskatchewan, which is supported by the Canada Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan.
Copyright information: This journal is © The Royal Society of Chemistry 2019. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.
  https://creativecommons.org/licenses/by-nc/3.0/