研究电流型电化学氨气传感器阳极碳载Ir(Ir/C)催化剂电催化NH3氧化性能.实验表明,在NaC lO4中性电解液中,Ir/C催化剂对NH3氧化的电催化性能与Ir载量有关.其中以Ir载量为10%(by m ass)的Ir/C催化剂的电催化性能最好,稳定性和灵敏度也最高...研究电流型电化学氨气传感器阳极碳载Ir(Ir/C)催化剂电催化NH3氧化性能.实验表明,在NaC lO4中性电解液中,Ir/C催化剂对NH3氧化的电催化性能与Ir载量有关.其中以Ir载量为10%(by m ass)的Ir/C催化剂的电催化性能最好,稳定性和灵敏度也最高.此外,NH3在不同载量的Ir/C催化剂上电催化氧化的电流密度与NH3浓度均呈现出良好的线性关系,此类Ir/C催化剂在电流型电化学氨气传感器中可望有良好的应用前景.展开更多
Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon(AC) carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir...Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon(AC) carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy(HAADF‐STEM) measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF (turn‐over‐frequency) of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst(approximately 1000 h^-1). Temperature‐programmed desorption of ammonia(NH3‐TPD) result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction(TPR) and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^+ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3+ species as an essential step for CH3I regeneration and acetyl formation.展开更多
文摘研究电流型电化学氨气传感器阳极碳载Ir(Ir/C)催化剂电催化NH3氧化性能.实验表明,在NaC lO4中性电解液中,Ir/C催化剂对NH3氧化的电催化性能与Ir载量有关.其中以Ir载量为10%(by m ass)的Ir/C催化剂的电催化性能最好,稳定性和灵敏度也最高.此外,NH3在不同载量的Ir/C催化剂上电催化氧化的电流密度与NH3浓度均呈现出良好的线性关系,此类Ir/C催化剂在电流型电化学氨气传感器中可望有良好的应用前景.
基金supported by the National Key R&D Program of China (2017YFB0602203)~~
文摘Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon(AC) carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy(HAADF‐STEM) measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF (turn‐over‐frequency) of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst(approximately 1000 h^-1). Temperature‐programmed desorption of ammonia(NH3‐TPD) result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction(TPR) and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^+ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3+ species as an essential step for CH3I regeneration and acetyl formation.