Jiancai Hou,Jiangliang Hu,Liping Chang,Jiancheng Wang,Zequan Zeng,Dongxia Wu,Xinmin Cui,Weiren Bao,Junxuan Yao
Cu-Ce mixed oxides with different Cu contents were synthesized through a sol–gel method, after which their effect on benzene combustion catalysis was evaluated. CeCu0.50 calcined at 300 °C (CeCu0.50–300) exhibited a high areal rate [2.0 × 10 −6 mol/(m 2 h)] and turnover frequency (0.16 s −1 ) at 170 °C, thus demonstrating the strong synergistic effect between CuO and CeO 2 . The catalyst durability and influence of H 2 O(g) on catalytic activity were also investigated. Correlation analyses between the catalytic activities and the amount of copper species, indicated that CuO x clusters and the Cu-[O x ]-Ce structure were the main active sites and bridge for oxygen transfer, respectively. Furthermore, benzene did not adsorb onto the copper species. The effect of temperatures on surface oxygen vacancies and oxygenated intermediates were also evaluated. Taken together, our findings provided key insights into the synergistic effects of different copper species on benzene combustion.
Electrochemical nitrogen reduction powered by renewable electricity is a promising strategy to produce ammonia. However, the lack of efficient yet cheap electrocatalysts remains the biggest challenge. Herein, hybrid Cu 2 O-CeO 2 -C nanorods are prepared on copper mesh through a metal-organic framework template route. The Cu-loaded Ce-MOF is thermally converted to Cu 2 O-CeO 2 heterojunctions with interfacial Cu-[O X ]-Ce structures embedded in carbon. Theoretical calculations reveal the lower formation energy of oxygen vacancies in Cu-[O X ]-Ce structures than in the Cu 2 O or CeO 2 phase. The Cu-[O X ]-Ce structures with oxygen vacancies enable the formation of interfacial electron-rich Cu(I) species which show significantly enhanced performance toward electrocatalytic nitrogen reduction with an NH 3 yield of 6.37 × 10 −3 µg s −1 cm −2 and a Faradaic efficiency of 18.21% in 0.10 m KOH at −0.3 V versus reversible hydrogen electrode. This work highlights the importance of modulation of charge distribution of Cu-based electrocatalysts to boost the activity toward nitrogen reduction.
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