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The construction of efficient catalysts is still the bottleneck for the industrialization of CO 2 methanation. Herein, a nitrogen (N)-doping strategy was developed to boost both activity and selectivity of the Ni/TiO 2 catalyst, wherein N-doped TiO 2 was prepared by a mild sol−gel method and employed as the support for Ni catalysts. In detail, CO 2 conversion at 350 °C over the Ni/TiO 2 and Ni/N 10 -TiO 2 catalysts was 9.6 and 41.7%, respectively. CH 4 selectivity at 400 °C over the Ni/TiO 2 and Ni/N 10 -TiO 2 catalysts was 44.1 and 84.6%, respectively. In comparison to the undoped Ni/ TiO 2 catalyst, the Ni/N 10 -TiO 2 catalyst had a smaller Ni size and enriched basic sites, leading to enhanced activity. The introduction of N dopants transformed TiO 2 phases from anatase into rutile and induced intimate contact between Ni nanoparticles and rutile TiO 2 , resulting in improved CH 4 selectivity. Substituted, interstitial, and oxidized N species were detected on the surface of N-doped Ni/ TiO 2 catalysts, among which substituted N was identified as the most critical species. The present work provides a facile and feasible strategy to promote both activity and selectivity of supported catalysts in CO 2 hydrogenation.

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