Owing to the peculiar synergistic interaction between CuO and CeO 2 at the interface, CuO/CeO 2 is one of the most efficient catalysts to purify a H 2 source, which is used in a proton exchange membrane fuel cell by preferential oxidation (PROX) of CO. The defective structure in CeO 2 is considered to be a crucial factor affecting the synergistic interaction. However, the defect−interaction relationship has not been well established due to the complex variation in different types of defects. Therefore, in this study, a novel ultrasound-assisted precipitation method was used to separately modulate diverse types of defects. The structural variation was explored by characterization techniques and theoretical calculations. It was found that the synergistic interaction was mainly related to two-electron defects on the CeO 2 surface. The two-electron defects could absorb O 2 to form the η 2 peroxide, and Cu ions could incorporate with the η 2 peroxide. Then, the two additional electrons in the two-electron defects would induce the electronic redispersion in CuO/CeO 2 , synchronously producing Cu + and Ce 3+ . The resulting Cu + and Ce 3+ were related to unsaturated CuO and redox capacity, which intimately affected the CO adsorption and oxygen activation. Thus, the catalytic performance was significantly promoted by increasing the amount of twoelectron defects in CeO 2 . Our study not only demonstrates a feasible way to finely control the synergistic interaction between CuO and CeO 2 but also deeply reveals the direct influence of two-electron defects on the CeO 2 surface on PROX.

An improved deposition method was employed to prepare a Pd/CeO2 catalyst, which exhibited highly efficient activity in low-temperature CO oxidation (LTO).

Since the conventional Haber-Bosch ammonia synthesis loop suffers from harsh process conditions, high energy consumption, and heavy pollution, the artificial catalytic synthetic NH3 has emerged as a promising alternative method for producing NH3. Meanwhile, nitrate (NO3 –) accumulation in the environment causes serious problems involving health and environmental issues. The urgent need to eliminate NO3 – and produce NH3 perfectly caters to the NO3 – reduction reaction (NO3RR) via an attractive electrocatalytic route. Cu-based catalysts exhibit an inhibiting effect on hydrogen evolution, rapid reduction kinetics, and stable catalytic performance, revealing remarkable advantages for NO3RR. In this review, we summarize the recent achievements of Cu-based catalysts in electrocatalytic NO3RR, discuss the detection methods for evaluating NO3RR performance, and introduce the fundamentals for understanding the thermodynamics and kinetics. This review can provide guidance and help for the rational design and development of non-noble metal catalysts in electrocatalytic NO3RR to NH3.

Practical applications of Pd-based catalysts are severely limited by sintering. A discontinuous shattered nanotube composed of ceria nanoparticles was employed as the shell in this work, and Pd@CeO2 core–shell nanotube catalysts were prepared using multiwalled carbon nanotubes as sacrificial templates, in which the noble metal was preserved at high dispersion, even after being treated at high temperature due to physical confinement and interaction confinement. The quantitative ratio of exposed Pd atoms to interacted Pd atoms could be readily manipulated by fabricating CeO2 shells with varied degrees of thickness and sparseness. The characterization and catalytic evaluation taken together reflected the roles of exposed Pd atoms which offered sites for CO adsorption and reaction, and interacted Pd atoms which activated the interfacial lattice oxygen and multiplied the adsorption oxygen. The enhanced catalytic performance would appear under an optimal distribution of Pd species after deliberate manipulation.

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