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<p>Pretreatment under controlled environments is a well-known strategy to improve the catalytic behavior of transition metal oxides, for CO oxidation. Here we report in-depth investigation of gas pretreatment in Co<sub>3</sub>O<sub>4</sub> spinel prepared by co-precipitation method, under controlled atmospheres (N<sub>2</sub>, H<sub>2</sub>, and O<sub>2</sub>) at moderate temperatures (150–250&#xa0;°C). Among all catalysts, H<sub>2</sub> pretreated at 250&#xa0;°C resulted in 100% conversion only at 148&#xa0;°C, a remarkable 70&#xa0;°C reduction compared to pristine Co<sub>3</sub>O<sub>4</sub> (218&#xa0;°C). This significant enhancement is coupled with exceptional long-term stability, as the catalyst maintained high reactivity for over 80&#xa0;h of continuous operation in the presence of high moisture, underscoring its robustness. Spectroscopic and DFT analyses attributed enhanced activity to dramatic increase in Co<sup>2+</sup>/Co<sup>3+</sup> ratio (0.42 → 1.95), and enriched defect oxygen species (O<sub>ads</sub>/O<sub>lat</sub> = 0.70), and slight expansion of lattice constant from 2.3 → 3.7. Mechanistic studies, including in-situ FTIR and theoretical simulations, a distinct signature of vacancy mediated Mars-van Krevelen pathway, with rapid carbonate/bicarbonate turnover. O<sub>2</sub>-TPD analysis showed a shift in lattice oxygen, along with the emergence of a feature in the moderate temperature region after H<sub>2</sub>-pretreatment, while CO-TPD revealed increased oxygen reactivity, with significant contributions from the weak and moderate temperature regions. These findings open new avenues for the design and optimization of transition metal oxide catalysts with unparalleled stability, activity, and selectivity for CO oxidation, making them viable alternatives to expensive noble-metal catalysts, with promising implications for industrial application.</p> Graphical abstract <p></p>

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Hydrogen-driven surface modification of Co3O4 catalysts for robust low-temperature CO oxidation

  • 期刊论文

  • 发表日期：

    2026年3月30日

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  • Numan Abbas,
  • Chen Sun,
  • Xin Qi,
  • Aleena Fatima Javed,
  • Fei Rao,
  • Lujun Zhu,
  • Yuhong Huang,
  • Leling Cao,
  • Gangqiang Zhu

摘要

Pretreatment under controlled environments is a well-known strategy to improve the catalytic behavior of transition metal oxides, for CO oxidation. Here we report in-depth investigation of gas pretreatment in Co3O4 spinel prepared by co-precipitation method, under controlled atmospheres (N2, H2, and O2) at moderate temperatures (150–250 °C). Among all catalysts, H2 pretreated at 250 °C resulted in 100% conversion only at 148 °C, a remarkable 70 °C reduction compared to pristine Co3O4 (218 °C). This significant enhancement is coupled with exceptional long-term stability, as the catalyst maintained high reactivity for over 80 h of continuous operation in the presence of high moisture, underscoring its robustness. Spectroscopic and DFT analyses attributed enhanced activity to dramatic increase in Co2+/Co3+ ratio (0.42 → 1.95), and enriched defect oxygen species (Oads/Olat = 0.70), and slight expansion of lattice constant from 2.3 → 3.7. Mechanistic studies, including in-situ FTIR and theoretical simulations, a distinct signature of vacancy mediated Mars-van Krevelen pathway, with rapid carbonate/bicarbonate turnover. O2-TPD analysis showed a shift in lattice oxygen, along with the emergence of a feature in the moderate temperature region after H2-pretreatment, while CO-TPD revealed increased oxygen reactivity, with significant contributions from the weak and moderate temperature regions. These findings open new avenues for the design and optimization of transition metal oxide catalysts with unparalleled stability, activity, and selectivity for CO oxidation, making them viable alternatives to expensive noble-metal catalysts, with promising implications for industrial application.

Graphical abstract