析氧反应(OER)被认为是电解水的关键限制步骤,已被广泛作为清洁能源方式用于解决能源和环境问题。钙钛矿氧化物(ABO_(3))具有可调的电子结构、高灵活性的元素组成,能在OER中表现出良好的催化活性。然而,钙钛矿氧化物的合成通常需要经历...析氧反应(OER)被认为是电解水的关键限制步骤,已被广泛作为清洁能源方式用于解决能源和环境问题。钙钛矿氧化物(ABO_(3))具有可调的电子结构、高灵活性的元素组成,能在OER中表现出良好的催化活性。然而,钙钛矿氧化物的合成通常需要经历长时间的高温,极易导致金属的聚集和影响材料的本征活性。气相微波技术可以显著缩短热处理时间,从而减少相关的碳排放。这项技术不仅解决了对碳中性过程日益增长的需求,而且还增加了对合成的控制,以避免产品的不良团聚。本文采用微波热冲法快速制备了二维(2D)多孔La_(0.2)Sr_(0.8)CoO_(3)钙钛矿。伴随微波过程的快速熵增可以有效地暴露La_(0.2)Sr_(0.8)CoO_(3)结构中丰富的活性位点。此外,高能微波冲击过程可以精准地将Sr2+引入到LaCoO_(3)的晶格中,通过增加Co的氧化态来增加氧空位量。这种锶元素取代镧引入的氧空位能极大提高催化剂的本征催化活性。对于碱性电解液中的OER应用,制备的La_(0.2)Sr_(0.8)CoO_(3)在10 m A·cm^(-2)下展现出了360 m V的过电位,Tafel斜率为76.6 mV·dec^(-1)。且在经历30000秒的长时间循环测试后仍能维持初始电流密度的97%。这项研究为高活性二维钙钛矿的合成提供了一种简便、快速的策略。展开更多
Two-dimensional(2D)single-layer δ-MnO_(2)(SLMO)with cations intercalated in the interlayers demonstrates specific structural characteristics,possessing superiority in the fields such as energy storage,catalysis,and s...Two-dimensional(2D)single-layer δ-MnO_(2)(SLMO)with cations intercalated in the interlayers demonstrates specific structural characteristics,possessing superiority in the fields such as energy storage,catalysis,and sensor.However,the synthesis technology of large-lateral-size SLMO nanosheets with high uniformity is rare,which hinders their correlated research.Herein,we report an intercalation-assisted exfoliation approach to produce large-sized SLMO nanosheets with high dispersity in aqueous solution.Few-layer K^(+)-intercalated δ-MnO_(2)(KMnO)nanosheets were used as a precursor to ensure complete exfoliation.On account of high dispersion and ultrathin 2D morphology,SLMO nanosheets self-assembled into a flexible and free-standing film to construct ordered nanochannels.A high surface charge density of 1.71 mC m^(-2) and proton mobility of 2.59×10^(-3) cm^(2) V^(-1) s_(-1) were achieved in the free-standing SLMO film.With the extraordinary properties and easily scaled fabrication of the 2D SLMO film,this approach will pave the way for the study of confined ion transportation and enable the easy construction of nanofluidic devices.展开更多
文摘析氧反应(OER)被认为是电解水的关键限制步骤,已被广泛作为清洁能源方式用于解决能源和环境问题。钙钛矿氧化物(ABO_(3))具有可调的电子结构、高灵活性的元素组成,能在OER中表现出良好的催化活性。然而,钙钛矿氧化物的合成通常需要经历长时间的高温,极易导致金属的聚集和影响材料的本征活性。气相微波技术可以显著缩短热处理时间,从而减少相关的碳排放。这项技术不仅解决了对碳中性过程日益增长的需求,而且还增加了对合成的控制,以避免产品的不良团聚。本文采用微波热冲法快速制备了二维(2D)多孔La_(0.2)Sr_(0.8)CoO_(3)钙钛矿。伴随微波过程的快速熵增可以有效地暴露La_(0.2)Sr_(0.8)CoO_(3)结构中丰富的活性位点。此外,高能微波冲击过程可以精准地将Sr2+引入到LaCoO_(3)的晶格中,通过增加Co的氧化态来增加氧空位量。这种锶元素取代镧引入的氧空位能极大提高催化剂的本征催化活性。对于碱性电解液中的OER应用,制备的La_(0.2)Sr_(0.8)CoO_(3)在10 m A·cm^(-2)下展现出了360 m V的过电位,Tafel斜率为76.6 mV·dec^(-1)。且在经历30000秒的长时间循环测试后仍能维持初始电流密度的97%。这项研究为高活性二维钙钛矿的合成提供了一种简便、快速的策略。
基金financially supported by the National Natural Science Foundation of China(51872101,51602115,and 61434001)the National Program for Support of Top-notch Young Professionals+1 种基金the Program for HUST Academic Frontier Youth Teamthe Director Fund of WNLO。
文摘Two-dimensional(2D)single-layer δ-MnO_(2)(SLMO)with cations intercalated in the interlayers demonstrates specific structural characteristics,possessing superiority in the fields such as energy storage,catalysis,and sensor.However,the synthesis technology of large-lateral-size SLMO nanosheets with high uniformity is rare,which hinders their correlated research.Herein,we report an intercalation-assisted exfoliation approach to produce large-sized SLMO nanosheets with high dispersity in aqueous solution.Few-layer K^(+)-intercalated δ-MnO_(2)(KMnO)nanosheets were used as a precursor to ensure complete exfoliation.On account of high dispersion and ultrathin 2D morphology,SLMO nanosheets self-assembled into a flexible and free-standing film to construct ordered nanochannels.A high surface charge density of 1.71 mC m^(-2) and proton mobility of 2.59×10^(-3) cm^(2) V^(-1) s_(-1) were achieved in the free-standing SLMO film.With the extraordinary properties and easily scaled fabrication of the 2D SLMO film,this approach will pave the way for the study of confined ion transportation and enable the easy construction of nanofluidic devices.
