Materials Research Express
·
2019
·Vol. 6
·期 11
·115544
·
IF 1.449
Yuhe Lu,Wei Wang,Feng Xie
Oxygen evolution reaction (OER) is an anodic reaction for copper electrowinning that occurs during the hydrometallurgical manufacturing process of copper, and the development of a highly active catalyst for the OER in an acidic electrolyte is of vital importance in terms of energy saving. Herein, we report a facile method to synthesize the SrIrO3 catalyst by solid-state reaction method assisted by mechanical activation. The results demonstrated that mechanical activation is critical to the successful fabrication of the SrIrO3 catalyst. XRD and TEM results confirmed the formation of SrIrO3 without other impurities, and XPS results revealed that some of the Ir species, including Ir4+, existed in +3 valence states. The catalyst shows both high catalytic activity for OER and stability in a sulfuric acid solution, with a Tafel slope of 48 mV dec−1 and almost no current decay after 1000 voltammetry cycles. This investigation is of fundamental and practical importance for synthesizing highly efficient SrIrO3 OER electro-catalysts to be potentially applied in copper electrowinning.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Maosheng You,Liangqi Gui,Xing Ma,Zhenbin Wang,Yin Xu,Jing Zhang,Jian Sun,Beibei He,Ling Zhao
IrO 2 and RuO 2 are the currently available electrocatalysts towards oxygen evolution reaction (OER) in acidic media. However, their commercial applications are still restricted by sluggish kinetics and limited stability. Herein, we highlight a facile anion engineering strategy in monoclinic SrIrO 3 (M-SrIrO 3 ) perovskite nanosheets for boosting acidic OER performance. The resultant novel S-doped M-SrIrO 3 electrocatalyst delivers a low overpotential of 228 mV at 10 mA cm −2 for 20 h to drive OER in 0.5 M H 2 SO 4 electrolyte, which is superior to the benchmark IrO 2 and favorably rivals most the state-of-the-art Ir-based perovskite electrocatalysts. Notably, the surface Sr leaching is confirmed during OER process, resulting in surface reconstruction of Ir(O, S) x amorphous layer. Theoretical calculations reveal that the S incorporation mitigates the strong binding of reaction intermediates, thus ultimately lowering the activation energy of OER kinetics. This protocol might offer an efficient approach of anion engineering in perovskites for various electrocatalysis.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Dongze Li,Wei Tu,Yuxiang Jin,Chao Wang,Song Jin,Wei Liu,Erhong Song,Zhangquan Peng,Junyuan Xu,Ligang Feng
Understanding the intricate mechanisms from material fabrication to catalytic reaction is crucial in energy chemistry. Herein, we elucidate the underlying mechanisms from catalyst to catalysis on Ir-segregated SrIrO 3 (Ir/SrIrO 3 ) as an efficient hydrogen evolution reaction (HER) catalyst in acidic conditions. During the phosphorization-assisted reduction process, in-situ spectroscopic analysis revealed that hydrogen radicals (H·) from the dissociation of P-H bonds attack the lattice oxygen at edge Ir-O sites, resulting in the segregation of Ir atoms and the formation of robust Ir-O interfacial structures between exsolved Ir clusters and the oxygen sites in SrIrO 3 . These interfacial structures are essential for the high performance of HER, while SrIrO 3 provides structural stability. The protons in the electrolyte are activated at the Ir nanocluster sites, incorporating oxygen in SrIrO 3 through the Ir-O interface, forming a reconstructed Ir-OH structure. This structure maintains both thermodynamic and electrochemical stability by adjusting hydrogen diffusion, embedding, and surface hydrogen coverage to sustain dynamic equilibrium during the catalytic process. Theoretical analysis confirms the necessity of the stable Ir-O interface via Ir- 5d and O- 2p orbital hybridization and hydrogen intercalation, optimizing charge redistribution, hydrogen bond length, and hydrogen adsorption free energy for enhanced HER kinetics. This study provides new insights into catalyst development by elucidating the relationship between catalyst structure and catalytic performance.
研究领域:
能源化学
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2018
·Vol. 9
·期 1
·1-9
·
IF 12.353
Yang Lan,Yu Guangtao,Ai Xuan,Yan Wensheng,Duan Hengli,Chen Wei,Li Xiaotian,Wang Ting,Zhang Chenghui,Huang Xuri,Chen Jie-Sheng,Zou Xiaoxin
The widespread use of proton exchange membrane water electrolysis requires the development of more efficient electrocatalysts containing reduced amounts of expensive iridium for the oxygen evolution reaction (OER). Here we present the identification of 6H-phase SrIrO 3 perovskite (6H-SrIrO 3 ) as a highly active electrocatalyst with good structural and catalytic stability for OER in acid. 6H-SrIrO 3 contains 27.1 wt% less iridium than IrO 2 , but its iridium mass activity is about 7 times higher than IrO 2 , a benchmark electrocatalyst for the acidic OER. 6H-SrIrO 3 is the most active catalytic material for OER among the iridium-based oxides reported recently, based on its highest iridium mass activity. Theoretical calculations indicate that the existence of face-sharing octahedral dimers is mainly responsible for the superior activity of 6H-SrIrO 3 thanks to the weakened surface Ir-O binding that facilitates the potential-determining step involved in the OER (i.e., O* + H 2 O → HOO* + H + + e ¯ ).
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）