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Tuning CO2 hydrogenation selectivity to obtain targeted value‐added chemicals and fuels has attracted increasing attention. However, a fundamental understanding of the way to control the selectivity is still lacking, posing a challenge in catalyst design and development. Herein, we report our new discovery in ambient pressure CO2 hydrogenation reaction where selectivity can be completely reversed by simply changing the crystal phases of TiO2 support (anatase‐ or rutile‐TiO2) or changing metal loadings on anatase‐TiO2. Operando spectroscopy and NAP‐XPS studies reveal that the determining factor is a different electron transfer from metal to the support, most probably as a result of the different extents of hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO2 hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design. [ABSTRACT FROM AUTHOR]

• Ruthenium nanoparticles incorporated in mesoporous carbon are reported for production of γ-valerolactone. • The incorporated catalysts demonstrate excellent reusability and thermal stability. • Leaching can be minimised by tailoring the mesoporous structure. • The mechanism of high reusability and thermal stability for incorporated ruthenium catalysts are studied. The hydrogenation of levulinic acid to γ-valerolactone with water as solvent is a crucial reaction for producing fine chemicals. However, the development of highly stable catalysts is still a major challenge. Here, we prepared a Ru nanoparticles incorporated in mesoporous-carbon (Ru-MC) catalyst to achieve high stability in acidic aqueous medium. The Ru-MC showed excellent catalytic performance (12024 h−1 turnover frequency) in the hydrogenation of LA-to-GVL. Compared with Ru supported on mesoporous carbon catalyst (Ru/MC) prepared by conventional wet impregnation method, the Ru-MC showed excellent reusability (more than 6 times) and thermal stability (up to 600 °C). Based on H 2 -TPR-MS characterization, it was proposed that the incorporated structure significantly increased the interaction between Ru nanoparticles and carbon support, which effectively prevent the leaching and sintering of Ru nanoparticles and contributed to increased high reusability and thermal stability of the Ru-MC. [ABSTRACT FROM AUTHOR]

• 1 wt% Ru loaded on N-doping carbon spheres catalysts (Ru/N-CS-850) were prepared. • N-doping carbon effectively improves the dispersion of Ru nanoparticles (Ru NPs). • The quaternary N plays the conclusive role for high dispersion of Ru NPs. • Ru/N-CS-850 has the highest absolute content of quaternary N and dispersity of Ru NPs. • Ru/N-CS-850 shows excellent yield for producing γ-valerolactone in water medium. Ru/carbon catalyst has been considered as a very active catalyst in aqueous-phase hydrogenation of bio-resourced carbonyl compounds. High dispersion of Ru NPs on a carbon support could enhance catalytic performance. In this work, well dispersed Ru nanoparticles on the surface of carbon spheres have been developed by the introduction of nitrogen-doping. Compared with carbon spheres without N-doping, the incorporation of the N-dopant with in the carbon matrix effectively improved the dispersion of Ru nanoparticles, which was confirmed by X-ray photoelectron spectroscopy (XPS) and CO chemisorption characterizations, finding that the presence of quaternary N was responsible for the high dispersion of Ru nanoparticles. Through adjusting the carbonization temperature from 400 to 850 °C, we have shown that the absolute content of quaternary N can be modulated from 3.2 to 22.4 mg g−1. As a result, the dispersion of Ru nanoparticles was improved from 29.8% to 70.9%. The Ru/N-CS-850 catalyst revealed excellent catalytic performance (9858 h−1 turnover frequency) for the hydrogenation of levulinic acid to γ-valerolactone, also demonstrated very high catalytic activity for other hydrogenation reactions. [ABSTRACT FROM AUTHOR]