Enhancing the Catalytic Activity of Zeolitic Imidazolate Framework‐8‐Derived N‐Doped Carbon with Incorporated CeO₂ Nanoparticles in the Oxygen Reduction Reaction

Abstract

Incorporation of CeO nanoparticles into the cavity of zeolitic imidazolate framework-8 (ZIF-8) was followed by high-temperature pyrolysis to generate CeO @N-doped carbon materials. Introduction of the CeO nanoparticles greatly enhanced the catalytic activity of the ZIF-8-derived carbon materials in the oxygen reduction reaction (ORR) owing to the presence of Ce and oxygen vacancies with high content of chemisorbed oxygen in CeO and the well-maintained skeleton of the original ZIF-8 with uniform mesoporous structure. The material treated at 900 °C (CeO @N-C-900) showed excellent ORR catalytic activity in both acidic and alkaline electrolyte. The ORR onset and half-wave potentials of CeO @N-C-900 were 1.003 and 0.908 V versus RHE, respectively, in 0.1 m KOH aqueous solution, which are comparable to those of Pt/C catalysts. Furthermore, it exhibited much better stability and methanol crossover tolerance than Pt/C, indicative of its good potential for applications in energy conversion.

CeO2 Encapsulated by Iron, Sulfur, and Nitrogen‐Doped Carbons for Enhanced Oxygen Reduction Reaction Catalytic Activity

“…The O 1s spectrum (Figure d) can be deconvoluted into three peaks at 529.7, 531.9 and 532.8 eV, which can be attributed to O γ , O β , O α , respectively, and the percentage of O β is 50.67 %. It has been accepted that O β , the chemisorbed oxygen, is closely related to make a great contribution to the ORR catalytic activity . The high‐resolution S 2p spectrum (Figure e) shows that S atoms exist in the form of C−S−C (163.8 eV for S 2p 3/2 , 165.2 eV for S 2p 1/2 ) and FeS (161.3 eV) .…”

“…Secondly, CeO 2 particles react with the carbon to introduce more oxygen vacancies into the carbon matrix during carbonization . The O β content in CeO 2 @Fe,S,N−C is higher than others (Table and Figure S7) and it is conducive to producing more chemical adsorption oxygen …”

“…CeO 2 NPS were prepared by using traditional hydrothermal method . Briefly, 2 g of the Ce(NO 3 ) 3 ⋅ 6H 2 O was completely dissolved in a mixture of CH 3 COOH/H 2 O (4 mL, V : V =1 : 1) under ultrasound conditions.…”

Preparation of Hollow CeO2/CePO4 with Nitrogen and Phosphorus Co‐Doped Carbon Shells for Enhanced Oxygen Reduction Reaction Catalytic Activity

“…The high‐resolution N 1s spectrum (Figure d) reveals that the doped N atoms exist in the form of pyridinic‐N (394.6 eV), pyrrolic‐N (397.8 eV), graphitic‐N (401.6 eV), and oxidized‐N (405.8 eV). Graphitic‐N and pyrrolic‐N are generally considered to make a great contribution to the ORR electrocatalytic activity . Based on the calculation via the fitted area, the percentage of the graphitic and pyrrolic‐N is 47.4 % and 32.3 %, respectively.…”

Fabricating Nitrogen‐Rich Fe−N/C Electrocatalysts through CeO2‐Assisted Pyrolysis for Enhanced Oxygen Reduction Reaction

“…Interestingly, as a widely‐recognized rare earth oxide, cerium oxide (CeO 2 ) has a unique oxygen storage and release capacity, prominent reversible redox property (Ce 3+ /Ce 4+ ) and possesses a large number of oxygen vacancies, which are beneficial to ORR catalytic processes . Especially, CeO 2 is possible to stabilize more nitrogen sources during catalyst synthesis process .…”