Hexagonal BaTiO(3- x)Hx Oxyhydride as a Water-Durable Catalyst Support for Chemoselective Hydrogenation

Masayoshi Miyazaki; Kiya Ogasawara; Takuya Nakao; Masato Sasase; Masaaki Kitano; Hideo Hosono

doi:10.1021/jacs.2c00976

Hexagonal BaTiO_{(3- x)}H_x Oxyhydride as a Water-Durable Catalyst Support for Chemoselective Hydrogenation

J Am Chem Soc. 2022 Apr 13;144(14):6453-6464. doi: 10.1021/jacs.2c00976. Epub 2022 Apr 5.

Authors

Masayoshi Miyazaki^{1

2}, Kiya Ogasawara¹, Takuya Nakao¹, Masato Sasase¹, Masaaki Kitano^{1

3

2}, Hideo Hosono^{1

4}

Affiliations

¹ Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
² Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan.
³ Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
⁴ National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.

PMID: 35380439
DOI: 10.1021/jacs.2c00976

Abstract

We present heavily H^--doped BaTiO_(3-x)H_x (x ≈ 1) as an efficient and water-durable catalyst support for Pd nanoparticles applicable to liquid-phase hydrogenation reactions. The BaTiO_(3-x)H_x oxyhydride with a hexagonal crystal structure (P6₃/mmc) was synthesized by the direct reaction of BaH₂ and TiO₂ at 800 °C under a stream of hydrogen, and the estimated chemical composition was BaTiO_2.01H_0.96. Density functional theory calculations and magnetic measurements indicated that such heavy H^- doping results in a metallic nature with delocalized electrons and a low work function. The potential of BaTiO_(3-x)H_x as a catalyst support was examined for the selective hydrogenation of unsaturated C-C bonds by Pd nanoparticles deposited on BaTiO_(3-x)H_x. We found that the turnover frequency for phenylacetylene hydrogenation per total amount of Pd in Pd/BaTiO_(3-x)H_x was the highest among the supported Pd catalysts reported to date. The strong electronic charge transfer between Pd and the support, as confirmed by X-ray photoelectron spectroscopy measurements, can be attributed to be responsible for such high catalytic activity. The combination of the BaTiO_(3-x)H_x support and Pd nanoparticles provides for the selective hydrogenation of unsaturated C-C bonds and highlights the validity of catalyst design that integrates H^- in support materials.