Promoted hydrogen activation and spillover over Pt/Co3O4 by facet engineering of Co3O4 for enhanced catalytic hydrogenation

TL;DR

Engineering the crystal facets of Co3O4 enhances hydrogen activation and spillover, boosting catalytic hydrogenation performance.

Contribution

Tailoring Co3O4 crystal facets modulates Pt nanoparticle electronic structure and hydrogen spillover for improved catalytic activity.

Findings

Pt/Co3O4-o with (111) facets shows highest hydrogenation activity with a TOF of 164.2 h−1.

Pt/Co3O4-o exhibits stronger H2 activation and weaker nitro group adsorption compared to Pt/Co3O4-c.

Facet engineering enhances hydrogen spillover and catalytic performance through electronic structure modulation.

Abstract

The exposed facets of supported metal catalysts play a crucial role in catalytic hydrogenation performance. However, the internal relationship between the support crystal facet and catalytic performance needs to be further explored. Herein, a series of well-defined Pt/Co3O4-x catalysts are fabricated with similar Pt nanoparticle sizes, identical metal loadings, and tailored Co3O4 crystal facets (x = o, t, c; where “o”, “t”, and “c” denote Co3O4 exposing predominantly (111), mixed (111)/(100), and (100) facets, respectively). The electronic structure of Pt nanoparticles and the hydrogen spillover capability of Pt/Co3O4 are modulated by exposing different crystal facets of Co3O4. For the 4-nitrophenol (4-NP) hydrogenation reaction with H2 as the hydrogen source, the Pt/Co3O4-o catalyst with more Pt0 species and stronger hydrogen spillover capability exhibits the best hydrogenation activity with a turnover frequency (TOF) of 164.2 h−1. Mechanistic studies indicate that, compared with Pt/Co3O4-c, the Pt/Co3O4-o exhibits weaker adsorption and activation of the nitro group, while its ability to activate H2 is stronger. The enhanced catalytic activity of Pt/Co3O4-o is attributed to promoted hydrogen activation and spillover. This work highlights support crystal facet engineering for regulating the electronic structure and hydrogen spillover effect, which provides in-depth insight into catalyst design and hydrogenation mechanism.

The (111) facet-induced electron-rich Pt nanoparticles on Co3O4 accelerate both H2 activation and hydrogen spillover dynamics, leading to a superior turnover frequency (TOF) in catalytic hydrogenation.

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