N-Doped Mesoporous In2 O3 for Photocatalytic Oxygen Evolution from the In-based Metal-Organic Frameworks

Xiaoyu Gan; Ruijin Zheng; Tianlin Liu; Jiao Meng; Ruiping Chen; Xuan Sun; Xun Sun

doi:10.1002/chem.201605576

N-Doped Mesoporous In₂ O₃ for Photocatalytic Oxygen Evolution from the In-based Metal-Organic Frameworks

Chemistry. 2017 May 29;23(30):7264-7271. doi: 10.1002/chem.201605576. Epub 2017 Mar 30.

Authors

Xiaoyu Gan^{1

2}, Ruijin Zheng², Tianlin Liu¹, Jiao Meng¹, Ruiping Chen³, Xuan Sun¹, Xun Sun²

Affiliations

¹ Key Laboratory for Colloid & Interface Chemistry, Shandong University, Education Ministry, Jinan, 250100, P.R. China.
² Key Laboratory of Functional Crystal Materials and Device, Shandong University, Ministry of Education, Jinan, 250100, P.R. China.
³ State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, P.R. China.

PMID: 28233355
DOI: 10.1002/chem.201605576

Abstract

As an excellent n-type semiconductor, indium oxide (In₂ O₃ ) is also a good candidate for photocatalysis such as light-induced water splitting. However, the efficiency of the oxygen evolution reaction (OER) underperforms in view of the wide band gap (BG) and fast charge recombination in In₂ O₃ . N-doping provides a sound method to narrow the BG and to prohibit the charge recombination by forming new energy levels between the valence band (VB) and the conduction band (CB). In this work, an In-based organic framework sod-ZMOF was used as a precursor to prepare the N-doped In₂ O₃ . After calcination, sod-ZMOF is transformed into N-doped In₂ O₃ nanocrystalline, in which the ligand within sod-ZMOF serves as the nitrogen source. In addition, sod-ZMOF acts as self-template during calcination to generate abundant nanopores within the In₂ O₃ frameworks, providing large specific surface area and active sites for OER. The BG is narrowed to 2.9 from 3.7 eV of the pure In₂ O₃ on account of the N-doping. N species are doped in both the substitutional and interstitial fashion, and the interstitial doping is believed to improve the photo-induced carrier separation by the formation of oxygen vacancies. As a consequence, the overpotential for OER is effectively decreased from the pure In₂ O₃ , and the electrocatalytic experiment proves superior catalytic activity with a high current density and long-term durability compared to the In₂ O₃ nanoparticles obtained from In(OH)₃ .

Keywords: N-doping; indium; metal-organic frameworks; oxygen evolution reaction; photocatalyts.